text:
|Publication number
|Publication type
|Application number
|Publication date
|Jun 5, 2001
|Filing date
|Jun 18, 1997
|Priority date
|Jun 18, 1997
|Fee status
|Publication number
|William G. Gardner
|Original Assignee
|Massachusetts Institute Of Technology
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (28), Non-Patent Citations (6), Referenced by (195), Classifications (16), Legal Events (4)
|External Links: USPTO, USPTO Assignment, Espacenet
Three-dimensional audio systems create an "immersive" auditory environment, where sounds can appear to originate from any direction with respect to the listener. Using "binaural synthesis" techniques, it is currently possible to deliver three-dimensional audio scenes through a pair of loudspeakers or headphones. Using loudspeakers involves greater complexity due to interference between acoustic outputs that does not occur with headphones. Consequently, a loudspeaker implementation requires not only synthesis of appropriate directional cues, but also further processing of the signals so that, in the acoustic output, sounds that would interfere with the spatial illusion provided by these cues are canceled. Existing systems require the listener to assume a fixed position with respect to the loudspeakers, because the cancellation functions correctly only in this orientation. If the listener moves outside a narrow equalization zone or "sweet spot," the illusion is lost.
It is well known that directional cues are embodied in the transformation of sound pressure from the free field to the ears of a listener; see Jens Blauert, Spatial Hearing (1983). A "head-related transfer function" (HRTF) represents a measurement of this transformation for a specific sound location relative to the listener's head, and describes the diffraction of sound by the torso, head, and external ear (pinna). Consequently, a pair of HRTFs, based on a known or assumed spatial location of the sound source, process sound signals so they appear to the listener to emanate from the source location—that is, the HRTFs produce a "binaural" signal.
It is straightforward to synthesize directional cues by convolving a sound with the appropriate HRTFs, thereby creating a synthetic binaural signal. When this is done using HRTFs designed for a particular listener, localization performance essentially matches free-field listening; see Wightman et al., J. Acoust. Soc. Am. 85(2):858-867 and 868-878 (1989). The use of non-individualized HRTFs-that is, HRTFs designed generically and not for a particular listener—results in poorer localization performance, particularly regarding front-back confusion and elevation judgments; see Wenzel et al., J. Acoust. Soc. Am. 94(1):111-123 (1993).
The sound travelling from a loudspeaker to the listener's opposite ear is called "crosstalk," and results in interference with the directional components encoded in the loudspeaker signals. That is, for each ear, sounds from the contralateral speaker will interfere with binaural signals from the ipsilateral speaker unless corrective steps are taken. Loudspeaker-based binaural systems, therefore, require crosstalk-cancellation systems. Such systems typically model sound emanating from the speakers and reaching the ears is using transfer functions; in particular, the transfer functions from two speakers to two ears form a 2�2 system transfer matrix. Crosstalk cancellation involves pre-filtering the signals with the inverse of this matrix before sending the signals to the speakers; in this way, the contralateral output is effectively canceled for each of the listener's ears.
Crosstalk cancellation using non-individualized head models (i.e., HRTFs) is only effective at low frequencies, where considerable similarity exists between the head responses of different individuals (since at low frequencies the wavelength of sound approaches or exceeds the size of a listener's head). Despite this limitation, existing crosstalk-cancellation systems are quite effective at producing realistic three-dimensional sound images, particularly for laterally located sources. This is because the low-frequency interaural phase cues are of paramount importance to sound localization; when conflicting high- and low-frequency localization cues are presented to a subject, the sound will usually be perceived at the position indicated by the low-frequency cues (see Wightman et al., J. Acoust. Soc. Am. 91(3):1648-1661 (1992)). Accordingly, the cues most critical to sound localization are the ones most effectively treated by crosstalk cancellation.
Existing crosstalk-cancellation systems usually assume a symmetric listening situation, with the listener located directly between the speakers and facing forward. The assumption of symmetry leads to simplified implementations, such as the shuffler topology described in Cooper et al., J. Audio Eng Soc. 37(1/2):3-19 (1989). One can compensate for a laterally displaced listener by delaying and attenuating one of the output channels (see U.S. Pat. Nos. 4,355,203 and 4,893,342). It is also possible to reformat the loudspeaker signals for different loudspeaker spread angles, as described, for example, in the '342 patent. It has not, however, been possible to maintain a binaural signal for a moving listener, or even for one whose head rotates.
The present invention extends the concept of three-dimensional audio to a moving listener, allowing, in particular, for all types of head motions (including lateral and frontback motions, and head rotations). This is accomplished by tracking head position and incorporating this parameter into an enhanced model of binaural synthesis.
Accordingly, in a first aspect, the invention comprises a tracking system for detecting the position and, preferably, the angle of rotation of a listener's head; and means for generating a binaural signal for broadcast through a pair of loudspeakers, the acoustical presentation being perceived by the listener as three-dimensional sound—that is, as emanating from one or more apparent, predetermined spatial locations. In particular, the system includes a crosstalk canceller that is responsive to the tracking system, and which adds to the binaural signal a crosstalk cancellation signal based on the position (and/or the rotation angle) of the listener's head. The crosstalk canceller may be implemented in a recursive or feedforward design. Furthermore, the invention may compute the appropriate filter, delay, and gain characteristics directly from the output of the tracking system, or may instead be implemented as a set of filters (or, more typically, filter functions) pre-computed for various listening geometries, the appropriate filters being activated during operation as the listener moves; the system is also capable of interpolating among the pre-computed filters to more precisely accommodate user movements (not all of which will result in geometries coinciding with those upon which the pre-computed filters are based).
In a second aspect, the invention addresses the high-frequency components not generally affected by the crosstalk canceller. Moreover, since the wavelengths involved are small, cancellation of these frequencies cannot be accomplished using a nonindividualized head model; attempts to cancel high-frequency crosstalk can actually sound worse than simply passing the high frequencies unmodified. Indeed, even when using an individualized head model, the high-frequency inversion becomes critically sensitive to positional errors because the size of the equalization zone is proportional to the wavelength. In the context of the present invention, however, high frequencies can prove problematic, interfering with dynamic localization by a moving listener. The invention addresses high-frequency interference by considering these frequencies in terms of power (rather than phase). By implementing the compensation in terms of power levels rather than phase adjustments, the invention avoids the shortcomings heretofore encountered in attempting to cancel high-frequency crosstalk.
Moreover, this approach is found to maintain the "power panning" property. As sound is panned to a particular speaker, the listener expects power to emanate from the directionally appropriate speaker; to the extent power output from the other speaker does not diminish accordingly, the power panning property is violated. The invention retains the appropriate power ratio for high frequencies using, for example, a series of shelving filters in order to compensate for variations in the listener's head angle and/or sound panning.
Preferred implementations of the present invention utilize a non-individualized head model based on measurements of a conventional KEMAR dummy head microphone (see, e.g., Gardner et al., J. Acoust. Soc. Am. 97(6):3907-3908 (1995)) both for binaural synthesis and transmission-path inversion. It should be appreciated, however, that any suitable head model—including individualized or non-individualized models—may be used to advantage.
The invention description below refers to the accompanying drawings, of which:
FIG. 1 schematically illustrates a standard loudspeaker listening geometry;
FIG. 2 schematically illustrates a binaural synthesis system implementing crosstalk cancellation;
FIG. 3 shows a binaural signal as the sum of multiple input signals rendered at various locations;
FIG. 4 is a schematic representation of a binaural synthesis system in accordance with the invention;
FIG. 5 is a more detailed schematic of an implementation of the binaural synthesis module and crosstalk canceller shown in FIG. 4;
FIGS. 6 and 7 are simplifications of the topology illustrated in FIG. 5;
FIGS. 8-10 are plots of various parameters of the invention for varying head-to-speaker angles;
FIG. 11 is an alternative implementation of the topology illustrated in FIG. 5;
FIG. 12 illustrates a one-pole, DC-normalized, lowpass filter for use in conjunction with the implementation of FIG. 11;
FIG. 13 illustrates linearly interpolated delay lines for use in conjunction with the implementation of FIG. 11;
FIG. 14 schematically illustrates the feedforward implementation of the invention;
FIG. 15 shows the addition of a shelving filter to implement high-frequency compensation for crosstalk;
FIGS. 16A, 16B illustrate practical implementations for the shelving filters illustrated in FIG. 15; and
FIG. 17 depicts a working circuit implementing high-frequency compensation for crosstalk.
a. Mathematical Framework
Binaural synthesis is accomplished by convolving an input signal with a pair of HRTFs:
where x is the input signal, x is a column vector of binaural signals, and h is a column vector of synthesis HRTFs. In other words, h introduces the appropriate binaural localizing cues to impart an apparent spatial origin for each reproduced source. Ordinarily, where binaural audio is synthesized rather than reproduced, a location (real or arbitrary) is associated with each source, and binaural synthesis function h introduces the appropriate cues to the signals corresponding to the sources; for example, each source may be recorded as a separate track in a multitrack recording system, and binaural synthesis is accomplished when the signals are mixed. To reproduce rather than synthesize binaural audio, the individual signals must be recorded with spatial cues encoded, in which case the h vector has, in effect, already been applied.
The vector x is a "binaural signal" in that it would be suitable for headphone listening, perhaps with some additional equalization applied. In order to deliver the binaural signal over loudspeakers, it is necessary to cancel the crosstalk. This is accomplished by filtering the signal with a 2�2 matrix T of transfer functions:
where y, the output vector of loudspeaker signals, may be termed a "binaural loudspeaker signal" and the filter T is the crosstalk canceller.
The standard two-channel listening geometry is depicted in FIG. 1. The signals eL and eR actually reaching the listener's ears are related to the speaker signals by
where e is a column vector of ear signals, A is the acoustical transfer matrix, and y is a column vector of speaker signals. The ear signals are considered to be measured by an ideal transducer somewhere in the ear canal such that all direction-dependent features of the head response are captured. The functions Axy each represent the transfer function from speaker X ε{L, R} to ear Y ε{L, R} and include the speaker frequency response, air propagation, and head response. These functions are well-characterized and routinely determined. A can be factored as follows:
where H is the "head-transfer matrix," a matrix of HRTFs normalized with respect to the free-field response at the center of the head (with no head present). The measurement point of the HRTFs, for example at the entrance of the ear canal—and hence the definition of the ear signals e—is left unspecified for simplicity, this being a routine parameter readily selected by those skilled in the art. S is the "speaker transfer matrix," a diagonal matrix that accounts for the frequency response of the speakers and the air propagation to the listener; again, these are routine, well-characterized parameters. SX is the frequency response of speaker X and AX is the transfer function of the air propagation from speaker X to the center of the head (with no head present).
FIG. 2 illustrates the playback system based on the above methodology. An input signal x is processed by two synthesis HRTFs HR, HL to create binaural signals XR, XL (based on predefined spatial positioning values associated with the source of x). These signals are fed through a crosstalk canceller implementing the transfer function T to produce loudspeaker signals YR, YL. The loudspeaker signals stimulate operation of the speakers PR, PL which produce an output that is perceived by the user. The transfer fictional A models the effects of air propagation, relating the output of speakers PR, PL the sounds eR, eL actually reaching the listener's ears. In practice, the synthesis HRTFs and the crosstalk-cancellation function T are generally implemented computationally, using conventional digital signal-processing (DSP) equipment. Such equipment can take the form of software (e.g., digital filter designs) running on a general-purpose computer and processing digital (sampled) signals according to algorithms corresponding to the filter function, or specialized DSP equipment having appropriate sampling circuitry and specialized processors configured for rapid execution of signal-processing functions. DSP equipment may include synthesis programs allowing the user to directly create digital signals, analog-to-digital converters for converting analog signals to a digital format, and digital-to-analog converters for converting the DSP output to an analog signal for driving, e.g., loudspeakers. By "general-purpose computer" is meant a conventional processor design including a central-processing unit, computer memory, mass storage device(s), and inputloutput (I/O) capability, all of which allows the computer to store the DSP functions, receive digital and/or analog signals, process the signals, and deliver a digital and/or analog output. Accordingly, block-diagram boxes appearing in the figures herein and denoting signal-processing finctions (other than those, such as A, that occur environmentally) are, unless otherwise specified, intended to represent not only the functions themselves, but also appropriate equipment for their implementation.
FIG. 3 illustrates how the binaural signal x may be the sum of multiple input signals rendered at various locations. Each sound xl', X 2. . . XN is convolved with the appropriate HRTF pair HL1, HR1; HL2, HR2. . . HLN, HRN, and the resulting binaural signals are summed to form the composite binaural signals XR, XL. For simplicity, in the ensuing discussion the binaural-synthesis procedure will be specified for a single source only.
Again with reference to FIG. 2, in order to exactly deliver the binaural signals to the ears, the crosstalk-cancellation filter T is chosen to be the inverse of the acoustical transfer matrix A, such that:
This implements the transmission-path inversion. H−1 is the inverse head-transfer matrix, and S−1 associates an inverse filter with each speaker output:
The 1/Sx terms invert the speaker frequency responses and the 1/Ax terms invert the air propagation. In practice, this equalization stage may be omitted if the listener is equidistant from two well-matched, high-quality loudspeakers. When the listener is off-axis, however, it is necessary to delay and attenuate the closer loudspeaker so that the signals from the two loudspeakers arrive simultaneously at the listener with equal amplitude; this signal alignment is accomplished by the 1/Ax terms.
In a realtime implementation, it is necessary to cascade the crosstalk-cancellation filter with enough "modeling" delay to create a causal system—that is, a system where the output of each filter derives from a previous input. In an acausal system, which arises only as a mathematical artifact of the modeled filter and cannot actually be realized, the filter output appears to anticipate the input, effectively advancing the input signal in time. In order to correct for this anomaly, the input signal to the acausal filter is delayed so that the filter has effective (i.e., apparent) access to future input samples. Adding a discrete-time modeling delay of m samples to Eq. 5, and representing the resulting signal in the frequency domain using a z-transform:
The amount of modeling delay needed will depend on the particular implementation. For simplicity, in the ensuing discussion modeling delay and the speaker equalization term S−1 are omitted. Thus, while Eq. 5 represents the general solution, for purposes of discussion the crosstalk-cancellation filters are represented herein according to
The inverse head-transfer matrix is given by:
where D is the determinant of the matrix H. The inverse determinant 1/D is common to all terms and determines the stability of the inverse filter. Because it is a common factor, however, it only affects the overall equalization and does not affect crosstalk cancellation. When the determinant is 0 at any frequency, the head-transfer matrix is singular and the inverse matrix is undefined.
As shown in Moller, Applied Acoustics 36:171-218 (1992), Eq. 9 can be rewritten as:
are the interaural transfer functions (ITFs), described in greater detail below. Crosstalk cancellation is effected by the -ITF terms in the off-diagonal positions of the righthand matrix. These terms estimate the crosstalk and send an out-of-phase cancellation signal into the opposite channel. For instance, the right input signal is convolved with ITFR, which estimates the crosstalk that will reach the left ear, and the result is subtracted from the left output signal. The common term 1/(1−ITFLITFR) compensates for higher-order crosstalks—i.e., the fact that each crosstalk cancellation signal itself transits to the opposite ear and must be cancelled. It is a power series in the product of the left and right interaural transfer functions, which explains why both ear signals require the same equalization signal: both ears receive the same high-order crosstalks. Because crosstalk is more significant at low frequences, as explained above, this term is essentially a bass boost. The lefthand diagonal matrix, which may be termed "ipsilateral equalization," associates the ipsilateral inverse filter 1/HLL with the left output and 1/HRR with the right output. These are essentially high-frequency spectral equalizers and, as is known, are important for perceiving rear sources using frontal loudspeakers. Sounds from the speakers, left unequalized, would naturally encode a frontal directional cue. Thus, in order to apply an arbitrary directional cue (e.g., to simulate a rear source), it is necessary first to invert the frontal cue.
Strictly speaking, the matrix H is invertible if and only if it is non-singular, i.e., if its determinant D≠0 (see Eq. 9). In practice, it is always possible to limit the magnitude of 1/D in frequency ranges where D is small, and in these frequency ranges the inverse matrix only approximates the true inverse. A stable finite impulse response (FIR) filter can be designed by incorporating suitable modeling delay into the inverse determinant filter.
The form of the inverse matrix given in Eq. 10 suggests a recursive implementation—that is, a topology where the estimated crosstalk is derived from the output of each channel and a negative cancellation signal based thereon is applied to the opposite channel's input signal. Various recursive topologies for implementing crosstalk-cancellation filters are known in the art; see, e.g, U.S. Pat. No. 4,1 18,599.
In particular, if the term 1/(1−ITFLITFR) is implemented using a feedback loop, then this will be realizable if the cascade of the two ITFs contains at least one sample of delay. Modeling the ITF as a causal filter cascaded with a delay, the condition for realizability is that the sum of the two interaural time delays (ITDs) be greater than zero:
Similarly, the feedback loop will be stable if and only if the loop gain is less than 1 for all frequencies:
Considering a spherical head model, these constraints are met when the listener is facing forward, i.e.:
where θh is the head azimuth angle, such that 0 degrees is facing straight ahead.
As explained previously, crosstalk cancellation is advantageously performed only at relatively low frequencies (e.g., ≦6 kHz). The general solution to the crosstalk-cancellation filter function given in Eq. 8 can be bandlimited so that crosstalk cancellation is operative only below a desired cutoff frequency. For example, one can define the transfer function T as follows:
where HLP and HHP are lowpass and highpass filters, respectively, with complementary magnitude responses. Accordingly, at low frequencies, T is equal to H−1, and at high frequencies T is equal to the identity matrix. This means that crosstalk cancellation and ipsilateral equalization occur at low frequencies, and at high frequencies the binaural signals are passed unchanged to the loudspeakers.
Alternatively, one can define T as:
Here the cross-terms of the head-transfer matrix are lowpass-filtered prior to inversion, as suggested in the '342 patent mentioned above. Applying a lowpass filter to the contralateral terms has the effect of replacing each ITF term in Eq. 10 with a lowpass-filtered ITF. This yields filters that are straightforwardly implemented.
Using the bandlimited form of Eq. 16, at low frequencies T is equal to H−1, but now at high frequencies (above the cutoff frequency fc of the lowpass filter), T continues to implement the ipsilateral equalization:
Using Eq. 16, when sound is panned to the location of a speaker, the response to that speaker will be flat, as desired. Unfortunately, the other speaker will be emitting power at high frequencies, which are unaffected by crosstalk cancellation (that is, the crosstalk-cancellation filter is not implementing the inverse matrix at these frequencies). As detailed below, the invention provides for re-establishing the power panning property at high frequencies.
b. Crosstalk Cancellation for a Moving Listener
As suggested above, the ITF represents the relationship between ear signals (i.e., sound pressures) reaching the two ears from a given source location, and is represented generally by the ratio:
where Hc is the contralateral response and Hi is the ipsilateral response. The ITF has a magnitude component reflecting increasing attenuation due to head diffraction as frequency increases, and a phase component reflecting the fact that the signal from the ipsilateral speaker reaches the ipsilateral ear before it reaches the contralateral ear (i.e., the interaural time delay, or ITD). Using a KEMAR ITF at 30 degrees incidence, it has been observed that at frequencies below 6 kHz, the frequency component of the ITF behaves like a lowpass filter with a gentle rolloff, but at higher frequencies the ITF magnitude has large peaks corresponding to notches in the ipsilateral response.
Because the sound wavefront reaches the ipsilateral ear first, it is tempting to think that the ITF has a causal time representation. In fact, the inverse ipsilateral response will be infinite and two-sided because of non-minimum-phase zeros in the ipsilateral response. The ITF therefore will also have infinite and two-sided time support. Nevertheless, it is possible to accurately approximate the ITF at low frequencies using causal (and stable) filters. Causal implementations of ITFs are needed to implement realizable, realtime filters that can model head diffraction.
It is known that any rational system function—that is, a function describing a filter that can actually be built—can be decomposed into a minimum-phase system cascaded with an allpass-phase system, which can be represented mathematically as:
According to this formulation, the ITF can be seen as the ratio of the minimum-phase parts of the contralateral and ipsilateral responses cascaded with an all-pass system whose phase response is the difference of the excess (allpass) phases of the ipsilateral and contralateral responses at the two ears (see Jot et al., "Digital Signal Processing Issues in the Context of Binaural and Transaural Stereophony," Proc. Audio Eng. Soc. Conv. (1995)):
It has been shown that for all incidence angles, the excess phase difference in Eq. 20 is approximately linear with frequency at low frequencies. Consequently, the ITF can be modeled as a frequency-independent delay cascaded with the minimum-phase part of the true ITF:
where ITD is the frequency-independent interaural time delay, and T is the sampling period.
The invention requires lowpass-filtered ITFs. Because these are to be used to predict and cancel acoustic crosstalk, accurate phase response is critical. High-order zero-phase lowpass filters are unsuitable for this purpose because the resulting ITFs would not be causal. In accordance with the invention, m samples of modeling delay are transferred from the ITD in order to facilitate design of a lowpass filter that is approximately (or exactly) linear phase with a phase delay of m samples. The resulting lowpassfiltered ITF may be generalized as follows:
such that
where L(ejω) is a causal filter—causality is enforced by the condition l[n] =0 for n<0—that describes head diffraction within some time shift, and m is the modeling delay of HLPF(ejω) taken from the ITD. The closest approximation is obtained when all the available ITD is used for modeling delay. However, it is also possible to utilize a parameterized implementation that cascades a filter L(z) with a variable delay to simulate an azimuth-dependent ITF. In this case, the range of simulated azimuths is increased if m is minimized.
There are two approaches to obtaining the filter L(z), differing in the method by which the ITF is calculated. One technique is based on the ITF model of Eq. 21, and entails (a) separating the HRTFs into minimum-phase and excess-phase parts, (b) estimating the ITD by linear regression on the interaural excess phase, (c) computing the minimum-phase ITF, and (d) delaying this by the estimated ITD. The other technique is to calculate the ITF by convolving the contralateral response with the inverse ipsilateral response. The inverse ipsilateral response can be obtained by computing its discrete Fourier transform (DFT), inverting the spectrum, and computing the inverse DFT. Using either method of computing the ITF, the filter L(z) can then be obtained by lowpass filtering the ITF and extracting l[n] from the time response starting at sample index floor(ITD/T−m).
The basic topology of a system implementing the invention is shown in FIG. 4. A series of sounds x1 . . . XN, each associated with a spatial location, are provided to a binaural synthesis module. In accordance with Eq. 1, module 100 generates a binaural signal vector x with the components XL XR. These are fed to a crosstalk-cancellation unit 110, which generates crosstalk-cancellation signals in the manner described above and combines the cancellation signals with XL and XR. The final signals are fed to a pair of loudspeakers 115 R, 115 L, which emit sounds perceived by the listener LIS. The system also includes a video camera 117 and a head-tracking unit 125. Camera 117 generates electronic picture signals that are interpreted in realtime by tracking unit 125, which derives therefrom both the position of listener LIS relative to speakers 115 R, 115 L and the rotation angle of the listener's head relative to speakers 115 R, 115 L. Equipment for analyzing video signals in this manner is well-characterized in the art; see, e.g., Oliver et al., "LAFTER: Lips and Face Real Time Tracker," Proc. IEEE Int. Conf on Computer Vision and Pattern Recognition(1997).
The output of tracking system 125 is utilized by modules 100, 110 to generate the binaural signals and crosstalk-cancellation signals, respectively. Preferably, however, tracking-system output is not fed directly to modules 100, 110, but is instead provided to a storage and interpolation unit 130, which, based on head position and rotation, selects appropriate values for the filter functions implemented by modules 100, 110. As a result of binaural synthesis and crosstalk cancellation, the sounds s1 . . . SN emitted by speakers 115 R, 115 L, and corresponding to the input signals x1 . . . XN, appear to the listener LIS to emanate from the spatial locations associated with the input signals.
FIG. 5 illustrates a recursive, bandlimited implementation of binaural synthesis module 100 and crosstalk canceller 110, which together compensate for head position and angle. The illustrated filter topology includes means for receiving an input signal x; a pair of right-channel and left-channel HRTF filters 200 L, 200 R, respectively; three variable delay lines 205, 210, 215 that dynamically change in response to head position and rotation angle data reported by tracking unit 125; two fixed delay lines 220, 225 that enforce the condition of causality, ensuring that the variable delays are always non-negative; a pair of right-channel and left-channel "head-shadowing" filters 230 L, 230 R, respectively, that model head diffraction and are also responsive to tracking unit 125; a pair of minimum-phase ipsilateral equalization filters 235 L, 235 R; and a pair of variable gains (amplifiers) 240 L, 240 R, which compensate for attenuation due to air propagation over different distances to the different ears. The recursive structure is implemented by a pair of negative adders 245 L, 245 R which, respectively, negatively mix the output of head-shadowing filter 230 R with the left-channel signal emanating from variable delay 205, and the output of head-shadowing filter 230 L with the right-channel signal emanating from fixed delay 220. Crosstalk cancellation is effected by head-shadowing filters 230 L, 230 R; variable delays 205, 210, 215; minimum-phase equalization filters 235 L, 235 R; and variable gains 240 L 240 R. The result is a pair of speaker signals YL, YR that drive respective loudspeakers 250 L, 250 R.
Operation of the implementation shown in FIG. 5 may be understood with reference to FIGS. 6 and 7, which illustrate simplifications of the approach taken. For simplicity of discussion, the various hypothetical filters of FIGS. 6 and 7 are treated as functions (and are not labeled as components actually implementing the functions).
In FIG. 6, the left and right components of the input signal x are processed by a pair of HRTFs HL, HR, respectively. The functions LL(z) and LR(Z) correspond to the filter functions L(z) described earlier. As these model the interaural transfer functions, each effectively estimates the crosstalk that will reach the contralateral ear. Accordingly, the crosstalk is cancelled by feeding the negative of this estimated signal to the opposite channel. By feeding back to the opposite channel's input rather than its output, higher-order crosstalks are automatically cancelled as well. The resulting additive signals tL, tR must then be equalized with the inverse ipsilateral response (1/HLL, 1/HRR). The delays ITDL/T, ITDR/T compensate. for the interaural time delays to the contralateral ears, while the delays mL, mR representing modeling delays inherent in the LL(z) and LR(Z) functions. The functions 1/(SLAL), 1/(SRAL) implement Eq. 6, compensating for speaker frequency responses and air propagation by delaying and attenuating the closer loudspeaker.
The structure of FIG. 6 is realizable only when both feedback delays (i.e., d(ITDL/T−mL), d(ITDR/T−mR) are greater than 1. To allow one of the ITDs to become negative, the total loop delay is coalesced into a single delay. This is shown in FIG. 7. The delays d(p1), d(p2) implement integer or fractional delays of p samples, with P1 and P2 chosen to be large enough so that all variable delays are always non-negative. The function z−1LR(z) represents LR(Z) cascaded with a single sample delay, the latter necessary to ensure that the feedback loop is realizable (since the loop delay d(ITDL/T+ITDR/T−mL−mR−1) is not prohibited from going to zero). The realizability constraint is then:
This constraint accounts for the single sample delay remaining in the loop and the modeling delays inherent in the lowpass head-shadowing filters LL(z), LR(Z).
With renewed reference to FIG. 4, equalization of the crosstalk-cancelled output signals tL, tR is effected by filters 235 L, 235 R and gains 240 L, 240 R. It should be stressed that the ipsilateral equalization filters 235 not only provide high-frequency spectral equalization, but also compensate for the asymmetric path lengths to the ears when the head is rotated. To convert the functions implemented by ipsilateral filters 235 to ratios, thereby facilitating separation of the asymmetric path-length delays according to Eq. 21, it is possible to use free-field equalized synthesis HRTFs; the ipsilateral equalization filter functions then become referenced to the free-field direction (i.e., an ideal incident angle to a speaker, usually 30� from each ear for a two-speaker system). It is most convenient to reference the synthesis HRTFs with respect to the loudspeaker direction θs.
Using this approach, the expression Hx/Hθ
where bx is the delay in samples for ear Xε{L, R} relative to the unrotated head position.
In practice, the speaker inverse filters 1/SX may be ignored. On the other hand, the air-propagation inverse filters 1/Ax are very important, because they compensate for unequal path lengths from the speakers to the center of the head. This effect may be modeled accurately as:
The combined ipsilateral and air-propagation inverse filter for channel X-i.e., the function implemented by filters 235 L, 235 R—is then:
A final simplification is to combine all of the variable delay into the left channel (i.e., into delay 215), which is accomplished by associating a variable delay of aL-bL with both channels. As a result, the head motions that change the difference in path lengths from the speakers to the ears will induce a slight but substantially unnoticeable pitch shift in both output channels.
The filter functions Hx, Hxx, ITDx, and Lx(z), as well as the delays ax and bx and the gains 1/kx, explicitly account for head angle and position. Consequently, their values must be updated as the listener's head moves. Rather than attempt to solve the complicated mathematics in realtime during operation, it is preferred to pre-compute a relatively large table of delay and gain parameters and filter coefficients, each set being associated with a particular listener geometry. The table may be stored as a database by storage and interpolation unit 130 (e.g., permanently in a mass-storage device, but at least in part in fast-access volatile computer memory during operation). As tracking system 125 detects shifts the listener's head position and rotation angle relative to the speakers, it accesses the corresponding functions and parameters, and provides these to crosstalk canceller 110—in particular, to the filter elements implementing the functions Hx, Hxx, ITDx, and Lx(z), ax, bx, and 1/kx. For listener geometries not precisely matching a stored entry, unit 130 interpolates between the closest entries.
Filters 230 L, 230 R may be implemented using low-order infinite impulse response (IIR) filters, with values for different listener geometries computed in accordance with Eqs. 21 and 22. HRTFs are well characterized, and Hx and Hxx can therefore be computed, derived empirically, or merely selected from published HRTFs to match various listener geometries. In FIG. 8, the L(z) filter function is shown for azimuth angles ranging from 5� to 45�.
Delay lines 205, 210, 215 may be implemented using low-order FIR interpolators, with the various components computed for different listener geometries as follows. The parameter ITDx is a function of the head angle with respect to speaker X, representing the different arrival times of signals reaching the ipsilateral and contralateral ears. ITDx can be calculated from a spherical head model; the result is a simple trigonometric function:
where D=17.5 cm is the spherical head diameter, c=344 m/sec is the speed of sound, and θx is the incidence angle of speaker X with respect to the listener's head, such that ipsilateral incidence results in positive angles and hence positive ITDs. Alternatively, the ITD can be calculated from a set of precomputed ITFs by separating the ITFs into minimum-phase and allpass-phase parts, and computing a linear regression on the allpass-phase part (the interaural excess phase). FIG. 9 shows both methods of computing the ITD for azimuths from 0 to 180�: the solid line represents the geometric model of Eq. 27, while the dashed line is the result of performing linear regression on the interaural excess phase.
The parameter bx is a function of head angle, the constant parameter θs (the absolute angle of the speakers with respect to the listener when in the ideal listening location), and the constant parameter ƒs (the sampling rate). The parameter bx represents the delay (in samples) of sound from speaker X reaching the ipsilateral ear, relative to the delay when the head is in the ideal (unrotated) listening location. Like ITDx, bx may be calculated from a spherical head model; the result is a trigonometric function:
where θH is the rotation angle of the head, such that θH=0 when the listener's head is facing forward, and the function s(θ) is defined as:
Finally, bL(θ) is defined as bR(−θ). An alternative to using the spherical head model is to compute the bx parameter by performing linear regression on the excess-phase part of the ratio of the HRTFs Hθ
The parameters ax and kx are functions of the distances dL and dR between the center of the head and the left and right speakers, respectively. These distances are provided along with the head-rotation angle by tracking means 125 (see FIG. 4). In accordance with Eq. 25, ax represents the air-propagation delay in samples between speaker X and the center of the head, and kx is the corresponding attenuation in sound pressure due to the air propagation. Without loss of generality, these parameters may be normalized with respect to the ideal listening location such that ax=0 and kx=1 when the listener is ideally situated. The equations for ax and kx are then:
where dx is the distance from the center of the head to speaker X (expressed in meters), and d is the distance from the center of the head to the speakers when the listener is ideally situated (also expressed in meters).
The implementation shown in FIG. 5 can be simplified by eliminating the ipsilateral equalization filters 235 L, 235 R as illustrated in FIG. 11. This approach uses efficient implementations for the head-shadowing filters 230 L, 230 R and for the variable delay lines 205, 210, 215. Preferably, each head-shadowing filter 230 L, 230 R is implemented as shown in FIG. 12, using a one-pole, DC-normalized, lowpass filter 260 cascaded with an attenuating multiplier 265. The frequency cutoff of lowpass filter 260, specified by the parameter u (and representing a simple function of ƒcf and ƒs), is preferably set between 1 and 2 kHz. The parameter v specifies the DC gain of the circuit, and is preferably between 1 and 3 db of attenuation. Using this implementation of head-shadowing filter 230, the modeling delays mL, mR are both zero, and the ITDL, ITDR parameters calculated as described above.
Variable delay lines 205, 210, 215 can be implemented using linearly interpolated delay lines, which are well known in the art. A computer-based device is shown in FIG. 13. Input samples enter the delay line 270 on the left and are shifted one element to the right each sampling period. In practice, this is accomplished by moving the read and write pointers that access the delay elements in computer memory. A delay of D samples, where D has both integer and fractional parts, is created by computing the weighted sum of two adjacent samples read from locations addr and addr+1 using a pair of variable gains (amplifiers) 275, 280 and an adder 285. The parameter addr is obtained from the integer part of D, and the weighting gain 0 <p<1 is obtained from the fractional part of D.
Another alternative to the implementation shown in FIG. 5 is the "feedforward" approach illustrated in FIG. 14, which utilizes the lowpass-filtered inverse head-transfer matrix of Eq. 16. This implementation includes means for receiving an input signal x; a pair of right-channel and left-channel HRTF filters 300 L, 300 R, respectively; a series of feedforward lowpass crosstalk-cancellation filters 305, 310, 315, 320; a variable delay line 325 (with P2, aR, and aL defined as above); a fixed delay line 330; and a pair of vari20 able gains (amplifiers) 340 L, 340 R. The determinant term of the crosstalk-cancellation filters is
where HLP is the lowpass term; and once again, the variable delay line and the variable gains compensate for asymmetric path lengths to the head. A pair of negative adders 355 L, 355 R negatively mix, respectively, the output of filter 315 with that of filter 305, and the output of filter 310 and with that of filter 320. The result is a pair of speaker signals YL, YR that drive respective loudspeakers 350 L, 350 R.
Each of the feedforward filters may be implemented using an FIR filter, and module 130 can straightforwardly interpolate between stored filter parameters (each corresponding to a particular listening geometry) as the listener's head moves. The filters themselves are readily designed using inverse filter-design techniques based on the discrete Fourier transform (DFT). At a 32 kHz sampling rate, for example, an FIR length of 128 points (4 msec) yields satisfactory performance. FIR filters of this length can be efficiently computed using DFT convolution. Per channel, it is necessary to compute one forward and one inverse DFT, along with two spectral products and one spectral addition.
c. High-Frequency Power Transfer
As discussed above, the bandlimited crosstalk canceller of Eq. 16 continues to implement ipsilateral equalization at high frequencies (see Eq. 17), since the ipsilateralequalization filters are not similarly bandlimited. Thus when a sound is panned to the location of either speaker, the response to the speaker will be flat; this is because the ipsilateral equalization exactly inverts the ipsilateral binaural synthesis response, an operation in agreement with the power-panning property. The other speaker, however, emits the contralateral binaural response, which violates the power-panning property. Of course, if crosstalk cancellation were not bandlimited and extended to high frequencies, the contralateral response would be internally cancelled and would not appear at the contralateral loudspeaker. Unfortunately, for the reasons described earlier, crosstalk cancellation causes more harm than benefit at high frequencies. To optimize the presentation of high frequencies while satisfying the power-panning property, the invention maintains bandlimited crosstalk cancellation (operative, preferably, below 6 kHz) and alters the high frequencies only in terms of power transfer (rather than phase, e.g., by subtracting a cancellation signal derived from the contralateral channel).
In accordance with this aspect of the invention, high-frequency power output at each speaker is modified so that the listener experiences power ratios consistent with his position and orientation. In other words, high-frequency gains are established so as to minimize the interfering effects of crosstalk. This is accomplished with a single gain parameter per channel that affects the entire high-frequency band (preferably 6 kHz-20 kHz).
Based on the assumption that high-frequency signals from the two speakers add incoherently at the ears, the invention models the high-frequency power transfer from the speakers to the ears as a 2�2 matrix of power gains derived from the HRTFs. (An implicit assumption for purposes hereof is that KEMAR head shadowing is similar to the head shadowing of a typical human.) The power-transfer matrix is inverted to calculate what powers to send to the speakers in order to obtain the proper power at each ear. Often it is not possible to synthesize the proper powers, e.g., for a right-side source that is more lateral than the right loudspeaker. In this case the desired "interaural level difference" (ILD) is greater than that achieved by sending the signal only to the right loudspeaker. Any power emitted by the left loudspeaker will decrease the final ILD at the ears. In such cases, where no exact solution exists, the invention sends the signal to one speaker, scaling its power such that the total power transfer to the two ears equals the total power in the synthesis HRTFs. Except for this caveat, the power-transfer approach is entirely analogous to the correction obtained by crosstalk cancellation. If it is omitted, very little happens to the high frequencies when the listener rotates his head. The power-transfer model of the present invention enhances dynamic localization by extending correction to these frequencies, helping to align the high-frequency ILD cue with the low-frequency localization cues while maintaining the power-panning property and avoiding the distortions associated with high-frequency crosstalk cancellation.
The high-frequency power to each speaker is controlled by associating a multiplicative gain with each output channel. Because the crosstalk-cancellation filter is diagonal at high frequencies, the scaling gains can be commuted to the synthesis HRTFs. Combining previous equations, the ear signals at high frequencies for a source x are given by:
where gL, gR are the high-frequency scaling gains. This equation may be converted to an equivalent expression in terms of power transfer. The simplest approach is to model the input signal x as stationary white noise and to assume that the transfer functions to the two ears are uncorrelated. Rewriting Eq. 31 in terms of signal variance by replacing the transfer functions with their corresponding energies,
where the energy of a discrete-time signal h[i], with corresponding DFT H[k], is given by:
The power transfer to the ears is then:
Replacing the actual power transfer to the ears with the desired power transfer corresponding to the synthesis HRTFs and solving for the scaling gains,
Eq. 32 is the crosstalk-cancellation filter function expressed in terms of broadband power transfer. If either row of the righthand side of Eq. 36 is negative, then a real solution is not obtainable. In this case, the gain corresponding to the negative row is set to zero, and the other gain term is set such that the total power to the ears is equal to the total desired power. The expression relating total desired power and total power follows directly from Eq. 31 by adding the two rows:
This expression is solved for one gain when the other gain is set to zero. Because all energies are non-negative, a real solution is assured.
In practice, it is found that the high-frequency model achieves only modest improvements over unmodified binaural signals for symmetric listening situations. However, the high-frequency gain modification is very important when the listener's head is rotated; without such modification, the low- and high-frequency components will be synthesized at different locations-the low frequencies relative to the head, and the high frequencies relative to the speakers.
High-frequency power compensation through gain modification can be implemented by creating a set of HRTFs with high-frequency responses scaled as set forth above, each HRTF being tailored for a particular listening geometry (requiring, in effect, a separate set of synthesis HRTFs for each orientation of the head with respect to the speakers). However, scaling the high-frequency components of the synthesis HRTFs in this manner corresponds exactly to applying a high-frequency shelving filter to each channel of the binaural source. (It is of course theoretically possible to divide the high-frequency bands into finer and finer increments, the limit of which is a continuous high-frequency equalization filter.) Using a shelving filter that operates on each channel of each binaural source, it is only the filter gains—rather than the synthesis HRTFs—that need be updated as the listener moves. Accordingly, a pre-computed set of gains gL and gR are established for numerous combinations of listening geometries and source locations, and stored in a database format for realtime retrieval and application. For example, as shown in FIG. 15, the implementation illustrated in FIG. 14 can be modified by adding a shelving filter 400 L, 400 R between the HRTF filters 300 L, 300 R and the crosstalk-cancellation filters 305, 310, 315, 320; in effect, filters 400 L, 400 R transform the HRTF output signals xL, xR into high-frequency-adjusted signals {circumflex over (x)}L, {circumflex over (x)}R. The shelving filters 400 L, 400 R have the same low-frequency phase and magnitude responses independent of the high-frequency gains.
Practical implementations for shelving filters 400 L, 400 R are shown for a single channel in FIGS. 16A and 16B. In FIG. 16B, the lowpass filter 405 preferably passes frequencies below 6 kHz, while highpass filter 410 feeds the high-frequency signals above 6 kHz to a variable gain element 415, which implements the high-frequency gain gx.
When HLP and HHP have complementary responses, HLP(z)=1−HLP(z), and this condition faciliates use of the simplified arrangement depicted in FIG. 16B. Unfortunately, it is not possible to use a low-order IIR lowpass filter for HLP because the low-frequency phase response of the shelving filter will depend on the high-frequency gain. Accordingly, a zero-phase FIR filter is used for HLP. Although this adds considerable computation, only one lowpass filter per channel is necessary to implement independent shelving filters for any number of sources, as shown in FIG. 17. This design is based on the following relationships implicit in FIG. 16B:
FIG. 17 depicts a working circuit for a single (left) channel having multiple input sources. In particular, xLi is the left-channel binaural signal for source i; the filters 415 Li . . . 415 LN each implement a value of gLi, the left-channel high-frequency scaling gain for source i; {circumflex over (x)}Li is the high-frequency-adjusted left-channel binaural signal; and the delay 420 implements a linear phase delay to match the delay of lowpass filter 405. The same circuit is used for the right channel, and the resulting high-frequency-adjusted binaural signals {circumflex over (x)}Li, {circumflex over (x)}Ri are routed to the crosstalk-canceller inputs.
It will therefore be seen that the foregoing represents a versatile approach to three-dimensional audio that accommodates listener movement without loss of imaging or sound fidelity. The terms and expressions employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.
|Cited Patent
|Filing date
|Publication date
|Nov 19, 1962
|Feb 22, 1966
|Bell Telephone Labor Inc
|Apparent sound source translator
|Sep 7, 1973
|Nov 18, 1975
|Beyer Eugen
|Method and apparatus for imparting to headphones the sound-reproducing characteristics of loudspeakers
|May 15, 1974
|Jun 8, 1976
|Eugen Beyer Elektrotechnische Fabrik
|Method and arrangement for controlling acoustical output of earphones in response to rotation of listener's head
|Feb 25, 1977
|Oct 3, 1978
|Victor Company Of Japan, Limited
|Stereophonic sound reproduction system
|Sep 3, 1976
|Oct 10, 1978
|Victor Company Of Japan, Limited
|Binaural multi-channel stereophony
|Sep 7, 1978
|Mar 11, 1980
|Makoto Iwahara
|Stage-expanded stereophonic sound reproduction
|Feb 21, 1978
|Aug 26, 1980
|Matsushita Electric Industrial Co., Ltd.
|Sound image localization control system
|Mar 12, 1980
|Dec 29, 1981
|Cohen Joel M
|Stereo image separation and perimeter enhancement
|Apr 5, 1979
|Jan 5, 1982
|Carver R W
|Dimensional sound recording and apparatus and method for producing the same
|Sep 8, 1980
|Oct 19, 1982
|Cohen Joel M
|Stereo image separation and perimeter enhancement
|Oct 22, 1984
|Mar 15, 1988
|Northwestern University
|Spatial reverberator
|May 31, 1985
|Apr 19, 1988
|Pioneer Electronic Corporation
|Method and apparatus for measuring and correcting acoustic characteristic in sound field
|Nov 12, 1986
|May 31, 1988
|Hughes Aircraft Company
|Stereo enhancement system
|Jan 22, 1987
|Mar 28, 1989
|American Natural Sound Company
|Three-dimensional auditory display apparatus and method utilizing enhanced bionic emulation of human binaural sound localization
|Nov 2, 1988
|Mar 20, 1990
|Cooper Duane H
|Head diffraction compensated stereo system with optimal equalization
|Aug 22, 1989
|Dec 4, 1990
|Cooper Duane H
|Head diffraction compensated stereo system with optimal equalization
|May 26, 1989
|Jun 11, 1991
|Matsushita Electric Industrial Co., Ltd.
|Apparatus for changing a sound field
|Aug 22, 1989
|Jul 23, 1991
|Cooper Duane H
|Head diffraction compensated stereo system
|Sep 2, 1988
|Sep 3, 1991
|Qsound Ltd.
|Sound imaging process
|May 2, 1991
|Apr 14, 1992
|Qsound Ltd.
|Sound imaging method and apparatus
|Jun 12, 1991
|Aug 4, 1992
|Cooper Duane H
|Head diffraction compensated stereo system
|Jan 29, 1992
|Dec 22, 1992
|The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
|Head related transfer function pseudo-stereophony
|Oct 31, 1991
|May 4, 1993
|Qsound Ltd.
|Sound imaging method and apparatus
|Aug 3, 1992
|Jul 26, 1994
|Cooper Duane H
|Head diffraction compensated stereo system with loud speaker array
|Nov 2, 1992
|Aug 9, 1994
|The 3Do Company
|Method for generating three dimensional sound
|Oct 4, 1993
|Aug 1, 1995
|The United States Of America As Represented By The Administrator Of National Aeronautics And Space Administration
|Multi-channel spatialization system for audio signals
|Jan 18, 1991
|Sep 19, 1995
|Sony Corporation
|Acoustic signal reproducing apparatus
|Oct 12, 1993
|Nov 14, 1995
|Matsushita Electric Industrial Co., Ltd.
|Sound environment simulator using a computer simulation and a method of analyzing a sound space
|Cooper et al., J. Aud. Eng. Soc. 37:3-19 (1989).
|Damake, J. Acoust. Soc. 1109-1115 (1971).
|Kotorynski, "Digital Binaural/Stereo Conversion and Crosstalk Cancelling", Proc. Audio Eng. Soc. Conv., Preprint 2949 (1990).
|Moller, Applied Acoustics 36:171-218 (1992).
|Sakamoto et al., J. Aud. Eng. Soc. 29:794-799 (1981).
|Schroeder et al., IEEE Int. Conv. Rec. 7:150-155 (1963).
|Citing Patent
|Filing date
|Publication date
|Nov 19, 1999
|Aug 27, 2002
|Texas Instruments Incorporated
|Method and apparatus for loudspeaker presentation for positional 3D sound
|Jun 29, 1999
|Oct 15, 2002
|Ricoh Company, Ltd.
|Method of determining a sound localization filter and a sound localization control system incorporating the filter
|May 8, 2000
|Dec 24, 2002
|Sony Corporation
|Vehicle-carried sound reproduction apparatus
|Jun 14, 1999
|Jun 10, 2003
|Central Research Laboratories Limited
|Method of synthesizing a three dimensional sound-field
|Oct 13, 1998
|Jul 8, 2003
|Srs Labs, Inc.
|Apparatus and method for synthesizing pseudo-stereophonic outputs from a monophonic input
|Nov 18, 1998
|Dec 23, 2003
|Jonathan S. Abel
|Crosstalk canceler
|Jun 12, 2000
|Mar 1, 2005
|Pioneer Corporation
|Audio device
|Apr 7, 2000
|Jun 7, 2005
|Zenith Electronics Corporation
|Multipath ghost eliminating equalizer with optimum noise enhancement
|Aug 7, 2001
|Jul 19, 2005
|Konami Corporation
|Fighting video game machine
|Jan 19, 2001
|Aug 9, 2005
|Nokia Corporation
|Transparent stereo widening algorithm for loudspeakers
|Oct 27, 2003
|Aug 30, 2005
|Britannia Investment Corporation
|Multi-channel audio surround sound from front located loudspeakers
|Jul 24, 2001
|Sep 20, 2005
|Sony Corporation
|Audio signal processing device, interface circuit device for angular velocity sensor and signal processing device
|Aug 6, 1999
|Feb 7, 2006
|Vulcan Patents Llc
|Estimation of head-related transfer functions for spatial sound representative
|Dec 14, 2000
|Apr 4, 2006
|Stmicroelectronics S.A.
|DSL transmission system with far-end crosstalk compensation
|Mar 17, 1999
|Mar 27, 2007
|Creative Technology Ltd
|Method of improving 3D sound reproduction
|Jun 8, 2005
|Jun 12, 2007
|Britannia Investment Corp.
|Enhanced multi-channel audio surround sound from front located loudspeakers
|Oct 21, 2003
|Aug 28, 2007
|Abel Jonathan S
|Crosstalk canceler
|Oct 10, 2002
|Jan 15, 2008
|1 . . . Limited
|Signal processing device for acoustic transducer array
|Apr 15, 2003
|Feb 19, 2008
|The Regents Of The University Of California
|Dynamic binaural sound capture and reproduction
|Feb 9, 2005
|Mar 17, 2009
|United States Of America As Represented By The Secretary Of The Air Force
|Efficient spatial separation of speech signals
|Mar 27, 2002
|Apr 7, 2009
|Cambridge Mechatronics Limited
|Method and apparatus to create a sound field
|Sep 29, 2000
|Aug 18, 2009
|Cambridge Mechatronics Limited
|Method and apparatus to direct sound
|Mar 10, 2005
|Sep 21, 2010
|Samsung Electronics Co., Ltd
|Apparatus and method of reproducing wide stereo sound
|Nov 14, 2005
|Nov 23, 2010
|Interval Licensing Llc
|Estimation of head-related transfer functions for spatial sound representation
|May 19, 2005
|Dec 28, 2010
|Samsung Electronics Co., Ltd
|Method, apparatus, and computer readable medium to reproduce a 2-channel virtual sound based on a listener position
|Jan 27, 2000
|Mar 29, 2011
|Sony Corporation
|Virtual sound source device and acoustic device comprising the same
|Sep 17, 2009
|Jul 5, 2011
|Thx Ltd
|Sound system and method of sound reproduction
|Jun 30, 2005
|Oct 4, 2011
|Microsoft Corporation
|Dynamic media rendering
|Nov 18, 2005
|Oct 25, 2011
|Victor Company Of Japan, Limited
|Video-audio recording apparatus and method, and video-audio reproducing apparatus and method
|Jan 19, 2009
|Apr 10, 2012
|Asustek Computer Inc.
|Audio system and a method for detecting and adjusting a sound field thereof
|Sep 8, 2005
|Apr 17, 2012
|Samsung Electronics Co., Ltd.
|Sound reproducing apparatus and sound reproducing method
|May 22, 2006
|May 8, 2012
|Bang & Olufsen A/S
|Recording, synthesis and reproduction of sound fields in an enclosure
|Sep 14, 2007
|May 22, 2012
|Lg Electronics Inc.
|Controller and user interface for dialogue enhancement techniques
|Oct 9, 2007
|Jun 12, 2012
|Siemens Audiologische Technik Gmbh
|Processing an input signal in a hearing aid
|Sep 14, 2007
|Aug 7, 2012
|Lg Electronics Inc.
|Dialogue enhancements techniques
|Sep 6, 2006
|Aug 14, 2012
|Koninklijke Philips Electronics N.V.
|Method of and device for generating and processing parameters representing HRTFs
|Jan 19, 2007
|Aug 21, 2012
|Nippon Hoso Kyokai
|Three-dimensional acoustic panning device
|Jun 5, 2007
|Aug 28, 2012
|Samsung Electronics Co., Ltd.
|Method and apparatus to reproduce stereo sound of two channels based on individual auditory properties
|Sep 14, 2007
|Sep 25, 2012
|Lg Electronics Inc.
|Dialogue enhancement techniques
|Sep 12, 2006
|Dec 25, 2012
|Samsung Electronics Co., Ltd.
|Method and apparatus to generate spatial sound
|Aug 12, 2011
|Jun 4, 2013
|Thx Ltd
|Narrow profile speaker configurations and systems
|Nov 14, 2008
|Jul 23, 2013
|Yamaha Corporation
|Virtual sound source localization apparatus
|Sep 6, 2006
|Aug 20, 2013
|Koninklijke Philips N.V.
|Method of and a device for generating 3D sound
|Jul 11, 2012
|Aug 27, 2013
|Koninklijke Philips N.V.
|Method of and device for generating and processing parameters representing HRTFs
|Jan 19, 2004
|Nov 26, 2013
|Yamaha Corporation
|Set-up method for array-type sound system
|Aug 7, 2007
|Dec 31, 2013
|Creative Technology Ltd
|Spatial audio enhancement processing method and apparatus
|Jun 21, 2012
|Jul 22, 2014
|Audience, Inc.
|Selection of system parameters based on non-acoustic sensor information
|May 10, 2011
|Sep 9, 2014
|Sony Corporation
|Audio signal processing device and audio signal processing method
|Jun 15, 2010
|Oct 28, 2014
|Sony Corporation
|Audio signal processing device and audio signal processing method
|Nov 28, 2006
|Jan 6, 2015
|Samsung Electronics Co., Ltd.
|Method and apparatus for expanding listening sweet spot
|Feb 9, 2007
|Feb 17, 2015
|Samsung Electronics Co., Ltd.
|Apparatus, method, and medium for removing crosstalk
|Aug 19, 2011
|Feb 24, 2015
|Cypress Semiconductor Corporation
|Adapting audio signals to a change in device orientation
|Apr 30, 2010
|Aug 11, 2015
|Microsoft Technology Licensing, Llc
|Audio spatialization using reflective room model
|Jun 26, 2013
|Sep 1, 2015
|Starkey Laboratories, Inc.
|Method and apparatus for localization of streaming sources in hearing assistance system
|Jul 10, 2013
|Sep 1, 2015
|Starkey Laboratories, Inc.
|Method and apparatus for hearing assistance in multiple-talker settings
|Mar 15, 2013
|Oct 27, 2015
|The United States Of America As Represented By The Secretary Of The Air Force
|Methods of using head related transfer function (HRTF) enhancement for improved vertical-polar localization in spatial audio systems
|Mar 3, 2008
|Nov 24, 2015
|Genaudio, Inc.
|Audio spatialization and environment simulation
|Jun 7, 2011
|Jan 5, 2016
|Sony Corporation
|Head related transfer function generation apparatus, head related transfer function generation method, and sound signal processing apparatus
|Aug 12, 2014
|Feb 23, 2016
|Turtle Beach Corporation
|Multi-dimensional parametric audio system and method
|Jun 20, 2012
|Mar 1, 2016
|Amazon Technologies, Inc.
|Enhanced stereo playback with listener position tracking
|Jun 20, 2012
|May 24, 2016
|Amazon Technologies, Inc.
|Enhanced stereo playback
|May 23, 2014
|May 31, 2016
|Harman Becker Automotive Systems Gmbh
|Sound system for establishing a sound zone
|Mar 12, 2013
|Jun 7, 2016
|Thx Ltd.
|Narrow profile speaker configurations and systems
|Nov 27, 2012
|Jun 21, 2016
|Lg Electronics Inc.
|Head mounted display and method of outputting audio signal using the same
|Sep 28, 2012
|Jun 28, 2016
|Qualcomm Incorporated
|Channel crosstalk removal
|Jun 26, 2013
|Aug 30, 2016
|Sony Corporation
|Head-related transfer function convolution method and head-related transfer function convolution device
|Jan 4, 2013
|Oct 4, 2016
|Sensor Platforms, Inc.
|System and method for device self-calibration
|Mar 24, 2015
|Nov 22, 2016
|Knowles Electronics, Llc
|Estimating and tracking multiple attributes of multiple objects from multi-sensor data
|Dec 21, 2012
|Dec 20, 2016
|Microsoft Technology Licensing, Llc
|Three-dimensional audio sweet spot feedback
|Jul 10, 2014
|Feb 7, 2017
|Digimarc Corporation
|Audio and location arrangements
|Aug 31, 2015
|Feb 28, 2017
|Starkey Laboratories, Inc.
|Method and apparatus for localization of streaming sources in hearing assistance system
|May 22, 2015
|Mar 28, 2017
|Microsoft Technology Licensing, Llc
|Systems and methods for audio creation and delivery
|Mar 23, 2015
|May 2, 2017
|Volvo Car Corporation
|System and method for distribution of 3D sound
|Aug 31, 2015
|May 2, 2017
|Starkey Laboratories, Inc.
|Method and apparatus for hearing assistance in multiple-talker settings
|Sep 28, 2010
|Jun 6, 2017
|Harman Becker Automotive Systems Manufacturing Kft
|Multichannel sound reproduction method and device
|Dec 14, 2000
|Jun 21, 2001
|Tomas Nordstrom
|DSL transmission system with far-end crosstalk compensation
|Aug 7, 2001
|Feb 21, 2002
|Konami Corporation
|Fighting video game machine
|Jul 24, 2001
|Feb 28, 2002
|Yuji Yamada
|Audio signal processing device, interface circuit device for angular velocity sensor and signal processing device
|Jan 19, 2001
|Jul 25, 2002
|Ole Kirkeby
|Transparent stereo widening algorithm for loudspeakers
|Jun 4, 2002
|Dec 4, 2003
|Elbit Systems Ltd.
|Method and system for audio imaging
|Jun 24, 2003
|Jan 8, 2004
|Kraemer Alan D.
|Apparatus and method for synthesizing pseudo-stereophonic outputs from a monophonic input
|Apr 15, 2003
|Apr 22, 2004
|The Regents Of The University Of California
|Dynamic binaural sound capture and reproduction
|Nov 12, 2002
|May 13, 2004
|Kantor Kenneth L.
|Method and apparatus for improving corrective audio equalization
|Mar 27, 2002
|Aug 5, 2004
|Anthony Hooley
|Method and apparatus to create a sound field
|Oct 21, 2003
|Sep 16, 2004
|Abel Jonathan S.
|Crosstalk canceler
|Sep 27, 2002
|Dec 9, 2004
|Nelson Philip Arthur
|Sound reproduction systems
|Oct 10, 2002
|Feb 24, 2005
|Goudie Angus Gavin
|Signal processing device for acoustic transducer array
|Oct 27, 2003
|Apr 28, 2005
|Polk Matthew S.Jr.
|Multi-channel audio surround sound from front located loudspeakers
|Feb 17, 2003
|Apr 28, 2005
|Troughton Paul T.
|Compact surround-sound system
|Jun 8, 2005
|Oct 13, 2005
|Polk Matthew S Jr
|Multi-channel audio surround sound from front located loudspeakers
|Mar 10, 2005
|Dec 8, 2005
|Kim Sun-Min
|Apparatus and method of reproducing wide stereo sound
|Jun 6, 2005
|Dec 8, 2005
|Expamedia, Inc.
|System for providing audio data and providing method thereof
|Jul 22, 2005
|Feb 2, 2006
|Shelley Katz
|Apparatus and method for producing sound
|Sep 8, 2005
|Mar 9, 2006
|Samsung Electronics Co., Ltd.
|Sound reproducing apparatus and sound reproducing method
|May 19, 2005
|Mar 23, 2006
|Kim Sun-Min
|Method, apparatus, and computer readable medium to reproduce a 2-channel virtual sound based on a listener position
|Nov 14, 2005
|Mar 30, 2006
|Vulcan Patents, Llc
|Estimation of head-related transfer functions for spatial sound representation
|Sep 29, 2005
|Mar 30, 2006
|Pryzby Eric M
|Crosstalk cancellation in a wagering game system
|Sep 30, 2005
|Mar 30, 2006
|Pryzby Eric M
|Environmental audio effects in a computerized wagering game system
|Oct 29, 2004
|May 4, 2006
|Miller Mark S
|Providing a user a non-degraded presentation experience while limiting access to the non-degraded presentation experience
|Jan 19, 2004
|Jul 13, 2006
|Anthony Hooley
|Set-up method for array-type sound system
|Jun 8, 2006
|Jan 11, 2007
|Algazi V R
|Dynamic binaural sound capture and reproduction in focused or frontal applications
|Jun 30, 2005
|Jan 11, 2007
|Microsoft Corporation
|Dynamic media rendering
|Oct 19, 2005
|Feb 1, 2007
|Fujitsu Limited
|Method and apparatus for processing information, and computer product
|Sep 12, 2006
|Apr 5, 2007
|Samsung Electronics Co., Ltd.
|Method and apparatus to generate spatial sound
|Nov 28, 2006
|Jun 7, 2007
|Samsung Electronics Co., Ltd.
|Method and apparatus for expanding listening sweet spot
|Jun 7, 2006
|Jul 12, 2007
|Samsung Electronics Co., Ltd.
|Method and medium for expanding listening sweet spot and system of enabling the method
|Sep 16, 2004
|Sep 27, 2007
|1... Limited
|Digital Loudspeaker
|Feb 9, 2007
|Nov 22, 2007
|Samsung Electronics Co., Ltd.
|Apparatus, method, and medium for removing crosstalk
|Aug 10, 2005
|Nov 22, 2007
|Non-Planar Transducer Arrays
|Aug 14, 2007
|Nov 29, 2007
|Abel Jonathan S
|Crosstalk Canceller
|Nov 18, 2005
|Jan 3, 2008
|Hisako Murata
|Video-Audio Recording Apparatus and Method, and Video-Audio Reproducing Apparatus and Method
|Aug 7, 2007
|Feb 7, 2008
|Creative Technology Ltd
|Spatial audio enhancement processing method and apparatus
|Aug 27, 2007
|Mar 6, 2008
|The Regents Of The University Of California
|Dynamic binaural sound capture and reproduction in focued or frontal applications
|Oct 9, 2007
|Jun 5, 2008
|Siemens Audiologische Technik Gmbh
|Processing an input signal in a hearing aid
|Jan 9, 2006
|Jun 12, 2008
|France Telecom
|Method And Device For Individualizing Hrtfs By Modeling
|Mar 9, 2006
|Jun 26, 2008
|Masaru Kimura
|Sound Image Localization Apparatus
|Jun 5, 2007
|Jul 3, 2008
|Samsung Electronics Co., Ltd.
|Method and apparatus to reproduce stereo sound of two channels based on individual auditory properties
|Jul 12, 2005
|Jul 3, 2008
|Miniature Surround-Sound Loudspeaker
|Sep 14, 2007
|Jul 10, 2008
|Lg Electronics Inc.
|Controller and User Interface for Dialogue Enhancement Techniques
|Sep 14, 2007
|Jul 10, 2008
|Lg Electronics, Inc.
|Dialogue Enhancements Techniques
|Sep 14, 2007
|Jul 10, 2008
|Lg Electronics, Inc.
|Dialogue Enhancement Techniques
|May 22, 2006
|Sep 4, 2008
|Bang & Olufsen A/S
|Recording, Synthesis And Reproduction Of Sound Fields In An Enclosure
|Sep 6, 2006
|Oct 16, 2008
|Koninklijke Philips Electronics, N.V.
|Method of and Device for Generating and Processing Parameters Representing Hrtfs
|May 30, 2007
|Dec 4, 2008
|Nokia Corporation
|Parameter Space Re-Panning for Spatial Audio
|Sep 6, 2006
|Dec 11, 2008
|Koninklijke Philips Electronics, N.V.
|Method of and a Device for Generating 3d Sound
|Mar 3, 2008
|Feb 19, 2009
|Genaudio, Inc.
|Audio spatialization and environment simulation
|Mar 13, 2008
|Mar 5, 2009
|Samsung Electronics Co., Ltd.
|Sound processing apparatus and sound processing method thereof
|Nov 14, 2008
|May 14, 2009
|Yamaha Corporation
|Virtual Sound Source Localization Apparatus
|Jan 19, 2009
|Aug 13, 2009
|Shou-Hsiu Hsu
|Audio System And a Method For detecting and Adjusting a Sound Field Thereof
|Jul 11, 2006
|Dec 3, 2009
|Compact surround-sound effects system
|Sep 17, 2009
|Mar 4, 2010
|Fincham Lawrence R
|Sound system and method of sound reproduction
|Jan 19, 2007
|Jun 24, 2010
|Nippon Hoso Kyokai
|Three-dimensional acoustic panning device
|Jun 15, 2010
|Dec 23, 2010
|Sony Corporation
|Audio signal processing device and audio signal processing method
|Mar 3, 2008
|Jan 6, 2011
|Nokia Corporation
|Apparatus for Capturing and Rendering a Plurality of Audio Channels
|Jul 11, 2005
|Jun 2, 2011
|Directional Microphone
|Apr 30, 2010
|Nov 3, 2011
|Microsoft Corporation
|Audio spatialization using reflective room model
|May 18, 2011
|Nov 24, 2011
|Harman Becker Automotive Systems Gmbh
|Individualization of sound signals
|Jun 7, 2011
|Dec 15, 2011
|Sony Corporation
|Head related transfer function generation apparatus, head related transfer function generation method, and sound signal processing apparatus
|Jul 7, 2011
|Jan 12, 2012
|Harman Becker Automotive Systems Gmbh
|Vehicle audio system with headrest incorporated loudspeakers
|Dec 28, 2011
|Aug 2, 2012
|Hon Hai Precision Industry Co., Ltd.
|Electronic device and method of dynamically correcting audio output of audio devices
|Jul 11, 2012
|Nov 1, 2012
|Koninklijke Philips Electronics N.V.
|METHOD OF AND DEVICE FOR GENERATING AND PROCESSING PARAMETERS REPRESENTING HRTFs
|Sep 28, 2010
|Jan 10, 2013
|Bang & Olufsen A/S
|Multichannel sound reproduction method and device
|Mar 15, 2013
|Aug 8, 2013
|Government Of The United States As Represented By The Secretary Of The Air Force
|Methods of using head related transfer function (hrtf) enhancement for improved vertical- polar localization in spatial audio systems
|Dec 21, 2012
|Aug 15, 2013
|Microsoft Corporation
|Skeletal modeling for world space object sounds
|Jun 26, 2013
|Oct 31, 2013
|Sony Corporation
|Head-related transfer function convolution method and head-related transfer function convolution device
|May 31, 2013
|Dec 12, 2013
|Aptina Imaging Corporation
|Optically-controlled speaker system
|Sep 28, 2012
|Apr 3, 2014
|Seyfollah S. Bazarjani
|Channel crosstalk removal
|Nov 27, 2012
|May 1, 2014
|Lg Electronics Inc.
|Head mounted display and method of outputting audio signal using the same
|Mar 16, 2014
|Sep 18, 2014
|Filter selection for delivering spatial audio
|Mar 16, 2014
|Sep 18, 2014
|Spatial audio aggregation for multiple sources of spatial audio
|May 23, 2014
|Nov 27, 2014
|Harman Becker Automotive Systems Gmbh
|Sound system for establishing a sound zone
|Aug 12, 2014
|Dec 4, 2014
|Turtle Beach Corporation
|Multi-dimensional parametric audio system and method
|Sep 16, 2014
|Apr 2, 2015
|Kabushiki Kaisha Toshiba
|Apparatus for controlling a sound signal
|Mar 23, 2015
|Oct 8, 2015
|Volvo Car Corporation
|System and method for distribution of 3d sound
|Jan 20, 2016
|May 19, 2016
|Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.
|Audio processor for orientation-dependent processing
|Jan 29, 2016
|May 26, 2016
|Avaya Inc.
|Immersive 3d sound space for searching audio
|Mar 25, 2016
|Jul 21, 2016
|Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.
|Concept for generating a downmix signal
|Jul 30, 2015
|Feb 2, 2017
|Roku, Inc.
|Audio preferences for media content players
|Aug 4, 2005
|May 23, 2012
|Method, apparatus, and computer readable medium to reproduce a 2-channel virtual sound
|Oct 10, 2007
|Feb 27, 2013
|Method and device for processing an input signal in a hearing aid
|May 18, 2011
|Nov 23, 2011
|Individualization of sound signals
|May 12, 2011
|Jan 11, 2012
|Vehicle audio system with headrest incorporated loudspeakers
|May 12, 2011
|Oct 5, 2016
|Aug 31, 2011
|Jul 4, 2012
|Adapting audio signals to a change in device orientation
|Aug 31, 2011
|Jun 8, 2016
|Jul 10, 2012
|Jan 15, 2014
|Method for auto-adjusting audio output volume and electronic apparatus using the same
|Mar 20, 2009
|Oct 7, 2010
|Technische Universit�t Dresden
|Device for adaptive adjustment of single reproducing area in stereophonic sound reproduction system to listener position in e.g. monitor, has speakers combined with processor via signal connection, where localization of signal is reproduced
|Mar 20, 2009
|Dec 22, 2011
|Technische Universit�t Dresden
|Vorrichtung und Verfahren zur adaptiven Anpassung des Singularwiedergabebereiches in sterophonen Schallwiedergabesystemen an H�rerpositionen
|Sep 25, 2002
|Nov 22, 2006
|Symbol Technologies Inc.
|Object locator system using a sound beacon and corresponding method
|Jun 13, 2002
|Dec 17, 2003
|Siemens Aktiengesellschaft
|Method for reproducing a plurality of mutually unrelated sound signals, especially in a motor vehicle
|Oct 10, 2003
|Aug 10, 2005
|Sony Corporation
|Audio signal processing method and processing device
|Oct 10, 2003
|Jun 13, 2012
|Sony Corporation
|Audio signal processing method and processing device
|Sep 25, 2002
|Jan 24, 2007
|Symbol Technologies Inc.
|Three dimensional object locator system using a sound beacon, and corresponding method
|Sep 25, 2002
|Jul 9, 2008
|Symbol Technologies Inc.
|Three dimensional object locator system using a sound beacon, and corresponding method
|May 27, 2005
|Aug 19, 2015
|Samsung Electronics Co Ltd
|Apparatus and method of reproducing wide stereo sound
|Jul 14, 2005
|Apr 18, 2007
|Matsushita Electric Industrial Co., Ltd.
|Sound image localization device
|Jul 14, 2005
|Mar 30, 2011
|Panasonic Corp
|Sound image localization device
|Oct 10, 2005
|Jun 27, 2007
|Dolby Laboratories Licensing Corporation
|Improved head related transfer functions for panned stereo audio content
|Oct 10, 2005
|Apr 16, 2014
|Dolby Laboratories Licensing Corporation
|Improved head related transfer functions for panned stereo audio content
|Nov 18, 2005
|Aug 1, 2007
|Victor Company Of Japan, Limited
|Video/audio recording apparatus and method, and video/audio reproducing apparatus and method
|Nov 18, 2005
|Nov 14, 2007
|Victor Company Of Japan
|Video/audio recording apparatus and method, and video/audio reproducing apparatus and method
|Sep 25, 2007
|May 11, 2011
|Siemens Audiologische Technik GmbH
|Processing of an input signal in a hearing aid
|Apr 24, 2014
|Nov 2, 2016
|Huawei Tech Co Ltd
|Virtual stereo synthesis method and device
|Sep 26, 2003
|May 6, 2004
|The Regents Of The University Of California
|Dynamic binaural sound capture and reproduction
|Jun 13, 2003
|Jan 20, 2005
|France Telecom
|Binaural signal processing with improved efficiency
|Oct 25, 2004
|May 19, 2005
|Britannia Investment Corporation
|Multi-channel audio surround sound from front located loudspeakers
|Jul 12, 2005
|Jan 19, 2006
|Portable speaker system
|May 22, 2006
|Nov 30, 2006
|Bang & Olufsen A/S
|Recording, synthesis and reproduction of sound fields in an enclosure
|May 22, 2006
|Apr 5, 2007
|Bang & Olufsen As
|Recording, synthesis and reproduction of sound fields in an enclosure
|Aug 31, 2011
|Mar 8, 2012
|Cypress Semiconductor Corporation
|Adapting audio signals to a change in device orientation
|Oct 25, 2011
|May 10, 2012
|Qualcomm Incorporated
|Systems, methods, apparatus, and computer-readable media for head tracking based on recorded sound signals
|Mar 14, 2014
|Sep 18, 2014
|Listening optimization for cross-talk cancelled audio
|Mar 14, 2014
|Nov 6, 2014
|Listening optimization for cross-talk cancelled audio
|Mar 17, 2014
|Sep 18, 2014
|Filter selection for delivering spatial audio
|Mar 17, 2014
|Nov 27, 2014
|Filter selection for delivering spatial audio
|U.S. Classification
|381/303, 381/1, 381/17
|International Classification
|Cooperative Classification
|European Classification
|Jun 18, 1997
Owner name: MASSACHUSETTS INSTITUTE OF TECHNOLOGY, MASSACHUSET
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GARDNER, WILLIAM G.;REEL/FRAME:008615/0469
Effective date: 19970618
|Dec 2, 2004
|Fee payment
Year of fee payment: 4
|Dec 5, 2008
|Fee payment
Year of fee payment: 8
|Dec 5, 2012
|Fee payment
Year of fee payment: 12


text:
Let your taste buds get carried away with these three new flavors
Posted on
Prepare to be blown away by these three new flavors, straight from the U.K. Tornado is available now, right here at Johnson Creek™.
Wake up your taste buds with Tornado, an exhilarating new range of stimulating flavors. They are 70/30 VG/PG blends, and can be found in the High-VG collection. High-VG e-liquids are crafted for use with RBA, RDA, RTA and sub-ohm tank devices.
Let Cool Blizzard give you an invigorating icy kick that really hits the spot! Alternatively maybe the scrumptious taste of sour apples in Cyclone is your thing, giving your palate an explosive sensation. Or... Experience the delicious taste of refreshing watermelon infused with fresh kiwi fruit with Twister.
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- Tags: New Product

subset: commoncrawl


text:
Sindy Lange – Blonde girl gets some interracial big dick
Released: April 8, 2014
Sindy Lange is a crazy white girl with a passion for big dicks. She wanted to find a nice hard cock for her to put in her mouth and in her wet pussy. She loves loves it so much that we hooked her up good. We hooked her up with Jack who has waited years before finally getting some action from her. Hes been waiting to fuck her for a while now and now is hi s chance so check out this movie its pretty hot. Enjoy!


text:
Okay so maybe I'm not really starving, but I do like the alliteration.
As our Shaw Plan Personalizer deal that was in place for six months came to an end (it was $62 including tax for some HD channels, selected channels, and extreme internet), I started practicing my negotiation skills in front of the mirror (no, not really) to see if I could get the discounted rate extended or see if I could get some other promotion. If I didn't figure something out, we would be paying $120 a month for cable and internet.
I called Shaw (after waiting for 20 minutes, no doubt) and asked to speak to one of their customer service representatives. Because I practiced negotiating for my cell phone contract last year, I thought I had the upper hand.
I even tried to see if I could downgrade the extreme internet to "just" high speed internet and see if that would take the sting away. It took the sting away by a measly $10. The cable and internet bill would still come to $120 or so a month.
I asked the representative if there were any promotions available.
"Miss, we often have free television channel promos that we give to our customers for free, right now, you can watch MTV Canada for free"
(my inside voice: I DON'T CARE ABOUT MTV CANADA! It sucks anyways and the last time I've watched that was 2 years ago when "The City" was on! I just want to pay less!)
I even threatened to leave Shaw and go to Telus.
This didn't phase the customer service rep. I guess it doesn't help that I wasn't on a contract, ha!
I then politely hung up and started brainstorming.
I thought that students must get some sort of a break on cable, seeing as students have no income and yet need some sort of distraction from studying. Students also need internet. They must give students a break.
I then called back and asked if there were any student discounts.
So for classic cable (which includes more channels than we were getting on our Shaw Plan Personalizer) and extreme internet, the bill would total $63 or so just because I was a post secondary student. Regular price would be $130 a month.
And how long does this goodness last? I thought it would be for another six months or something, but noooooo…
It lasts as long as I am a student! So for two more years, I will get cheap cable and internet.
That alone makes my miserable part time work and full time student life worthwhile! Oh, and it's not me who is addicted to cable, it's my boyfriend. Him and his Walking Dead episodes *sigh*.
Here's what you have to do to get in on this deal:
- First of all, Shaw said you can't be a full time student (I believe it was only full time students who are eligible) and live in your parents home or even in their basement… because that would mean your parents are getting cheap cable.
- Print out a copy of your tuition statement to prove to them you're legit and in school
- Print out a copy of your enrollment or acceptance letter or other proof to say that you are in post-secondary school (My program is online and it was still fine!)
- Bring your student ID
- Find the Shaw customer service centre (for me it is in the lovely Shaw tower in Coal Harbor- pretty fancy!)
- Bring your student ID and your copies of tuition and enrollment to the Shaw Customer Service Centre
- Speedwalk/race to the customer service line up alongside a mid-forties male who sees you in his peripheral vision and obviously doesn't care that you are female and wanting to get in the line up too (hey, what about ladies first? Maybe I didn't look like a lady that day?? lol)
- Wait in line for 20-30 minutes with other people who look disgruntled
- Show them the goods and they will look at you and make sure your ID is real and then give you the discount!
Et Voila! $750+ annually saved on cable.
This alone makes me want to be a perpetual student. Perhaps Million Dollar Journey should go to MBA school so he can get this deal too? 😉
Readers, are there any other "WOW" discounts you know of that gives students an advantage?


text:
Unit Converter Pro« Personalization & Tools « Downloads
|January 2, 2014
|8 times
|Personalization & Tools
Unit converter is a tool in the extended set of the Smart Tools collection.
It is the ad-free version. Ads are replaced by useful texts.
There are already a lot of unit conversion apps on the market. However, most are inconvenient and difficult to use because of a poor and complicated UI.
This Unit converter app is most intuitive and simple with a beautiful and optimized UI that is designed for the casual user like you. It goes without saying that you would not be able to find a better one. Try it out.
This app has 14 categories with essential units used in your daily life.
* Supported Units list
– Basic : length (distance), area, weight (mass), volume
– Life : temperature, time, speed, fuel consumption
– Science : pressure, force, work (energy), power
– Misc. : angle, data
It supports customized units automatically depending on your country. Also, landscape mode for tablet PC is supported.
At the moment, there are 2 empty tabs. When you have any requests, please send an email to me. firstname.lastname@example.com
For more information, see my Youtube videos and blog. Thank you.


text:
Begin New Search
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Kathy O
member for 8 years, 5 months, 27 days
Add to MyFriends
Bio and Links
Hi! My name is Kathy O'Brien and I currently live in Vancouver, Washington. It's been a real joy to photograph several cemeteries in Shasta County, California and upload them to Find A Grave.
Feel free to use any of my photos. No need to send me a request, just give me proper credit for the photo. I am happy to transfer memorials to anyone who wants to manage them. Please send transfer requests and requests for changes using the EDIT TAB.
My personal interests are Buckreus and Zilch in Wisconsin, emigrating from Germany, and Rehnblom and Leksell in Iowa, originating in Sweden.
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6,988 Memorials Added
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Linda Davis
RE: s. carl miller
Thanks so much for the help.
Added by
Linda Davis
on Sep 03, 2016 9:35 PM
Linda Davis
s. carl miller
Hi Kathy,
I was wondering if you know who was the funeral home who handled his funeral?
He died Dec. 14, 1964 and I am looking for a
Thanks in advance for any help.
Linda Davis
Added by
Linda Davis
on Sep 03, 2016 5:41 PM
Kathaleen Moceikis
Michael Bruce Langer
Hi Kathy,
In doing research on Ancestry, I ran across this. Michael Bruce Langer is my son. Michael Bruce passed away on August 29, 1973, not August 31, 1973. If you could please change the date of his death it would be greatly appreciated. Just want the record to be right.
Best wishes,
Kathaleen Ferguson Moceikis
Added by
Kathaleen Moceikis
on Jun 16, 2016 11:59 AM
Jeffrey Duarte
Joseph Meraz Memorial# 40171580
I was wondering if you photographed this marker because you are related to Joseph. He is my 1st cousin once removed. I am interested if knowing you are a relative.
Added by
Jeffrey Duarte
on Jun 01, 2016 3:41 PM
Pam Cairns Palmer
Just wanted to say....you are AWESOME!!!! Thanks for all the wonderful photographs and memorials! May God bless you in all that you do!
Added by
Pam Cairns Palmer
on Apr 13, 2016 8:45 AM
Shanna (Flaherty) Pierce
RE: Donald Flaherty
Thank you.
Added by
Shanna (Flaherty) Pierce
on Mar 29, 2016 5:32 PM
Thomas Wolf
Thanks Kathy for updating his memorial so quickly, very much appreciated. Thanks for all you do as well. Happy hunting!
Added by
on Jan 10, 2016 4:20 PM
Marcia Lynne vonGunden
Transfer & thank you
Hello again Kathy,
Thank you for your generosity in transferring:
Mary Catherine Martin Orr # 68488675
to my care.
With your help, I have successfully connected her with her parents, seven siblings, two husbands and three children. As I receive more information, I will be adding it to Our shared memorial.
With sincerest appreciation,
# 47059326
Added by
Marcia Lynne vonGunden
on Oct 25, 2015 6:06 AM
cousin's memorial
Hello! Can you please transfer memorial #68489741 to me? She was my first cousin and I'd like to put her with the other family memorials that I manage. Thank you!
Added by
on Oct 21, 2015 1:50 AM
Doctor Quincy Dillard
Hey Kathy,
Thank you for connecting Doc to his father. So far, I haven't been able to find his mother.
I've found that according to some of his other family members that his first name was actually just "DOC". So could I get you to go ahead and change that too.
Thank you so much!!!
Added by
on Aug 06, 2015 2:50 PM
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text:
Mary Springer graduated from Canyon High School in Santa Clarita in 2006. After earning a CRA Ed Foundation scholarship, Mary went on to study hospitality and tourism management and restaurant operations at San Diego State University. She graduated in the spring of 2011 and now works for Brad Metzger Restaurant Solutions as a management recruiter.
WHo has been your biggest career influence?
It's hard to say one person who has been the biggest influence in my career. I've had the pleasure of meeting and working with many great people, who probably had a greater impact on my outlook in my career than they would realize. I believe in always allowing yourself to be inspired! Although, at this point I've pretty much always asked Carl Winston, School Director of the L. Robert Payne School of Hospitality and Tourism Management, his opinion on career moves, even if I haven't always done what he's recommended.
Who is your culinary idol?
I've had the pleasure of working with and meeting many of L.A.'s finest chef's and restaurateurs. But one person that I have not had to pleasure of meeting or working with, but I who think is brilliant, is Bill Chait. He opened a restaurant near my home and of course I was so excited that I went in opening night. I couldn't get a table until the last seating and was there pretty late, but I saw that he was there working and making sure everything was okay until pretty much the end of the night! I came back a week later (yes it was that good) and AGAIN he was there making sure everything was okay. He's one that I get really excited about when he is creating something new.
What is your signature dish?
A grain (lentils, quinoa, etc.) and Parmesan Broccoli. Cook Broccoli in a pan with oil, water, black pepper, and Lawry's seasoning salt and throw some fresh Parmesan on there. Eat over a bed of Lentils or something like that.
What is your favorite restaurant in California?
That is extremely difficult to say. I feel like I find a new favorite restaurant all the time! My flavor of week is a small restaurant in Studio City called the Tuning Fork.
WHat advice would you give to high school students interested in the hospitality and culinary industries?
It's easy to get fixated and entirely focused on the company you're working for, or your own little world you're working in. Don't forget to see the bigger picture and pay attention to what else is out there. Allow yourself to be inspired again. If you're getting burnt out, take a day or weekend trip to another city and see what's going on in the restaurant scene there. It may be something new and fresh and give you a new perspective! This is a business of passion, but it's easy to get stuck in the day to day.
What made your college experience unique?
I had a lot of different hobbies and things that interested me in college, so I broke away from the mold a little. I was in a Co-ed Business Fraternity. I was in a play. I tried Speech and Debate for a bit. I even minored in English. I did all of these (and more!) just because they were things that I was interested in and wanted to experience while I had the chance. When I heard they were thinking of starting a restaurant focused organization, I jumped on the opportunity was very heavily involved in that my last two years. It took five years to get my degree, but I can say that I experienced it all and left feeling fulfilled. I never had a shortage of classes I was taking, but for me it was more about the experiences outside of them.
How did your CRAEF scholarship benefit you?
It was really life changing for me. I was working two jobs trying to support myself while at San Diego State. Getting the scholarship allowed me to work a lot less and concentrate on extracurricular and student organizations, particularly the restaurant club, SDSU Foodies, which I served as President. I really think that being able to focus on this is what helped me get job offers upon graduation and has even helped me in my career growth up to today.
okay, last question: what would your last meal be?
As much as I love artisanal fresh farm-to-table cuisine, I would probably go with Cheese Fries as my last meal.


text:
Definition Edit
The first-mover incentive (also called the first-mover advantage) refers to the the incentive/advantage that the first entity that offers a particular technology has over its competitors.
Overview Edit
|For an ISV interested in attracting users, there may be an advantage to offering the first and, for a while, only application in its category that runs on a new PC operating system. The user base of the new system may be small, but every user of that system who wants such an application will be compelled to use the ISV's offering. Moreover, if demand for the new operating system suddenly explodes, the first mover will reap large sales before any competitors arrive. An ISV thus might be drawn to a new PC operating system as a "protected harbor."[1]
"The initial occupant of a market segment may benefit from a number of advantages such as preemption of resources, advantageous relationships with customers and suppliers, and early profits for re-investment in infrastructure."[2]
References Edit
- ↑ United States v. Microsoft Corp., 65 F.Supp.2d 1, 12 (D.D.C. 1999) (full-text) (Finding of Fact 42).
- ↑ Spectrum Policy in the Age of Broadband: Issues for Congress, at 11 n.62.


text:
Brand Freebies domain is for sale.
Interested in making an offer?
Please email:
1. Two-word domain best suitable for online Supermarket where consumer can get free samples and freebies of their favorite brand products.
2. Brandable keyword domain.
3. Comes with customized vector Logo.
If you are interested in making an offer on this domain, please email: