# Use of plus 4/minus 10 (+4/-10) switches?

Discussion in 'Sound, Music, and Intercom' started by Anonymous067, Aug 30, 2008.

1. ### Anonymous067BANNED USER

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When using audio gear, how do I know which to set all my gear to.
When I bring my IEM system into a venue and want to hook it up to their aux send off the board, which switch SHOULD it be on?
I know its a different measuring system but it has always confused me.

Explain?

2. ### waynehoskinsActive Member

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Location:
Arlington, TX
It's signal level. Pro gear operates at +4 dBu (is it dBu? dBsomething); consumer line-level gear operates at -10 dBsomething.

So if you're interfacing to pro gear, you probably want it at +4; if consumer, -10. If you hit a consumer piece of gear with a +4 signal, that's +14dB to it, so you're hard clipping its input stages. If you hit pro gear with a -10 signal, it's weak (-14 dB), so you have to crank it.

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Almost.

I was working through the math of this the other night for a project. +4dBu is a voltage signal, referenced to 0.775 V. Thus, 4 dBu is actually 1.228V. (4 = 20*log(V/0.775); thus 0.2 = log(V/.775) and V = 0.775*(10^0.2))

-10 dBV is also a voltage signal, but referenced to 1V. So this signal would be 316 mV (-10 = 20*log(V/1); thus -0.5 = log(V) and V = 10^-0.5 = 0.316).

Thus, the difference in voltage would be: V = 20*log(1.228/0.316) = 11.79, or approximately 12 dB difference in signal strength.

THe short answer to your question is that almost all consoles reference their outputs to 4dBu, unless noted. Most IEM gear will probably have a switch on it. So just set the switch to +4 dBu and plug it up.

4. ### waynehoskinsActive Member

Messages:
782
49
Location:
Arlington, TX
I couldn't remember if they were referenced the same or not, and I was too lazy to check. Well done.

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The text passage is a discussion about audio gear, specifically the use of +4/-10 switches and the signal levels they represent. It includes a detailed explanation of the voltage levels and the difference between +4 dBu and -10 dBV.
no_question

while the passage contains a detailed explanation and some calculations, it does not present a specific mathematical question that requires an answer. the calculations are part of the explanation provided in response to a general inquiry about audio gear settings.
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
# Use of plus 4/minus 10 (+4/-10) switches?

Discussion in 'Sound, Music, and Intercom' started by Anonymous067, Aug 30, 2008.

1. ### Anonymous067BANNED USER

Messages:
833
28
When using audio gear, how do I know which to set all my gear to.
When I bring my IEM system into a venue and want to hook it up to their aux send off the board, which switch SHOULD it be on?
I know its a different measuring system but it has always confused me.

Explain?

2. ### waynehoskinsActive Member

Messages:
782
49
Location:
Arlington, TX
It's signal level. Pro gear operates at +4 dBu (is it dBu? dBsomething); consumer line-level gear operates at -10 dBsomething.

So if you're interfacing to pro gear, you probably want it at +4; if consumer, -10. If you hit a consumer piece of gear with a +4 signal, that's +14dB to it, so you're hard clipping its input stages. If you hit pro gear with a -10 signal, it's weak (-14 dB), so you have to crank it.

Messages:
1,435
153
Occupation:
Engineer
Location:
Chicago, IL
Almost.

I was working through the math of this the other night for a project. +4dBu is a voltage signal, referenced to 0.775 V. Thus, 4 dBu is actually 1.228V. (4 = 20*log(V/0.775); thus 0.2 = log(V/.775) and V = 0.775*(10^0.2))

-10 dBV is also a voltage signal, but referenced to 1V. So this signal would be 316 mV (-10 = 20*log(V/1); thus -0.5 = log(V) and V = 10^-0.5 = 0.316).

Thus, the difference in voltage would be: V = 20*log(1.228/0.316) = 11.79, or approximately 12 dB difference in signal strength.

THe short answer to your question is that almost all consoles reference their outputs to 4dBu, unless noted. Most IEM gear will probably have a switch on it. So just set the switch to +4 dBu and plug it up.

4. ### waynehoskinsActive Member

Messages:
782
49
Location:
Arlington, TX
I couldn't remember if they were referenced the same or not, and I was too lazy to check. Well done.

Messages:
318
user
The text passage is a discussion about audio gear, specifically the use of +4/-10 switches and the signal levels they represent. It includes a detailed explanation of the voltage levels and the difference between +4 dBu and -10 dBV.

TYPE: NO_QUESTION

While the passage contains a detailed explanation and some calculations, it does not present a specific mathematical question that requires an answer. The calculations are part of the explanation provided in response to a general inquiry about audio gear settings.