what's happening when setting the speaker levels?

[marivera75]

I have often wondered what is actually happening when you are setting the speaker levels on a 5.1 audio receiver using a sound level meter.
I have always assumed that when you raise the speaker decibel level that you are increasing the gain of the preamp for that particular channel. If this is the case would one actually be distorting the sound by increasing the speaker levels to there maximum because the preamp would be working at maximum capacity?
I have also considered that maybe by increasing the speaker level you are simply increasing the gain of the amp itself. In which case, would increasing the volume above 0 cause that channel to clip or distort at loud volumes, because you are demanding more from it then at the 0 position full scale?
When setting the speaker level should one set the main channels at the 0 position and then adjusts the other speaker accordingly so that no speakers are set above 0 or does it matter?

What is actually happening when you raise the speaker levels of an audio receiver? Are you requesting more gain from the preamp? Or the amp of a particular channel? Does increasing the speaker level above 0 increases the possibility that that channel will clip or distort at high volumes?

 

[AcuDefTechGuy]

I think it may increase distortion, but the distortion may be insignificant and inaudible.

 

[Djizasse]

I don't know how they implement it, but it's possible they check all the levels and set the max power according to the highest level set, ex: if you set rear channels at +5 then max level will correspond to +5 and all the other channels will get -5. This would prevent distortion.
It's like equalization, you should not add gain, just cuts.

 

[BMXTRIX]

I would say that it might be possible to clip the audio, but considering that your A/V receiver has a pre-amp that typically will be run well under 0dB levels and won't likely clip at any reasonable volumes, that the added push you may be putting on certain speakers may have minimal ipact on the audio in general.

Since, for the most part, signals are being attenutated before amplification, the bit of less attenuation may even be good for the overall quality of the signal up until the point where you reach 0dB within the receiver itself.

Bottom line, is that if you are cranking your speakers to a point where the receiver is basically maxed out then you likely are overdriving everything, and the couple of speakers that are being overdriven a 'bit' more are the least of your issues.

Keep in mind, that your most critical speakers, generally speaking, are your fron L&R mains, and these are generally not gained or attenuated, but used as the 0 gain fixed set by which all others are matched to. So, the speakers that may be the ones hardest driven, are likely the ones which are also most accurate throughout the preamp stage.