Voltage to speakers with receiver?

[axro]

I have a 5.1 channel Yamaha receiver. I don't know how many watts it is total.

There is nothing wrong with it, I'm just kinda playing around with my multimeter because I'm going to make a color organ.

If I measure the voltage going to one of the speakers I get something like 9 to 15 millivolts DC. That can't be right is it? I tried measuring AC(which I thought it should be) and I got nothing. Am I missing something here?

 

[ronv]

It's ac. The meter probably can't respond to the music frequencies and "burst mode". The color organ will have a kind of sample and hold to fix that. Try something like 2001 with a long low bass note.

 

[crutschow]

A small amount of DC is likely normal if it's a direct coupled output. And you should see AC when you are playing music. You may have to turn up the volume a bit.

 

[Reloadron]

Anyone who has looked at the audio signal to a speaker on an oscilloscope can attest to the fact that it is a collection of frequencies and amplitudes.

A good way to go about looking at these signals would likely be to remove the speaker(s) and replace with a load resistor of 4, 8, or 16 ohms depending on amplifier output matching the impedance. Then on the line input to the audio amp inject a sine wave at a known frequency of 400 Hz, to 1 KHz to a few KHz. Increase the output level to the load (without toasting the load resistor) and observe the audio signal voltage on a good AC Voltmeter.

Ron