got to remember when you got flat line on a rta it does not sound best but is what your shooting for in a sq match. it should be with in 3 dbs of all the bars next to each other

First off. I wouldn't use Pink noise to check output levels of an amplifier. There's just too much going on to get an accurate reading.

Second. What are you measuring the voltage with? It really doesn't surprise me that the pink noise had a lower output on a simple voltmeter.

Third. I wouldn't trust tones downloaded from anywhere unless I verified the tone to be true to the frequency and actually at 0db.

If you know somebody that has an o-scope, hook that up and see what the peak to peak voltage is using a good commercial CD with a true 1khz 0db tone and a true 50hz 0db tone.

As for this statement

That's true when you are running the system in something like a RTA freq out event. That's not what any of us use in real sound quality competitions. My RTA curve used in judging is FAR from flat. I can't say I've ever used a rta to measure amp output anyway. I would be interested in hearing that method. Or maybe I just mis-understood something.

Sadistic- i am measuring the ac voltage output of the audio channels. the zx6400 is rated at 85x4, so 100 watts isn't out of the realm of possibilty at 4ohm, it's the fact that one i got a reading of 50watts (recorded at 0dB) and then the next day i downloaded a 50Hz and 1000Hz sinwave from the net. the 4 channel putout more power with the downloading recording while the monoblocks putout less. the only thing i can think of is that these tones were not recorded at the same level.

TtownCLS- i didn't want to but that's all the was on the Bass Mekanik and dB Drag CD's. that's why i downloaded a 1000Hz test tone, but i just don't know how it was recorded. (you hit that point) and i am using a DMM.

Thanks for the replys. Ima have to give Sam Horn a call!