Focal Performance Auditor+ AP-4340SI 4/3/2 Channel Car Amplifier (70RMS*4 190RMS*2) Whether you're talking about audio products for home, car, or studio, the name Focal always comes up when the conversation centers around sound quality. Their Auditor+ Series AP-4340SI 4-channel amp makes a great candidate for powering any high-performance car audio system. This amp puts out 70 watts RMS per channel with very low distortion and very wide frequency response, so you can be sure your speakers or subs will sound their best.When you're using the AP-4340SI to power four speakers, you can use the high-pass filters on the front and rear channels to eliminate the low bass for a cleaner sound. If you want to run full-range speakers and a sub, you'd use the high-pass filters on your front channels, then bridge the rear channels together to drive your sub, using the low-pass filter to optimize the bass.In 2-channel mode, the AP-4340SI puts out 190 watts RMS per channel, so you could use it to power a pair of high-performance speakers or subwoofers. A selectable bass boost lets you extend the low-frequency response.