Ok everyone,
maybe i'm missing something.
I know my amp is powerful (ESX 175.2) so I decided
to set the gains without my ears and with a volt meter.
This amp does 500 watts at 4 ohms mono.
So the apparent voltage is 44.7 to produce 500 watts.
I set everything up from the deck (Kenwood KDC-7009) it's a 1.8v pre out deck.
Anyway i dial in the amp's gain and i get to 44/45 volts.
Then i put everthing back together.
I pop in a cd and the power output was something like 40 watts at most.
Tell me am I missing something?
Please help.
L.

 

You set the gain with a sine wave with the amp unloaded?

First, music has much less "energy" than a sine wave. It won't give you readings as high as a sine wave on your DMM.

Second, with the amp loaded if you are only measuring voltage you don't know the *actual* impedance. You would need a current clamp to see that. Very rarely is your 4 ohm load *actually* 4 ohms

So... in short, if it sounds fine, you are good to go. I generally set gains by ear for my daily cars to get everything level matched to my ears, since they will be doing the listening, rather than trying to get too technical with it.