i finally got time today to mess with the gain and the voltmeter.....a few problems/questions....

1. when they say you need "A CD with a sine-wave test tone recorded at 0dB reference level in the frequency range to be amplified (40-50 Hz works well). Do not use attenuated test tones (-10dB ~ -20dB, etc.)" do they mean that the sine-wave test tone should be at 40-50Hz or your HU output frequency should be at 40-50Hz???

i thought that i followed the instructions exactly and set the cd player bass output to 40Hz and poped in the BASSMEKANIK's Cd and put on track 40 (sine waves match track number) and got the gain on the amp with the voltmeter to be around 38.7V, as soon as it went to track 41 the voltage was completly off. the bass sounds clearer now but no where near as loud as it was before.

"cd player bass output to 40Hz"
are you talking about setting the electronic low-pass crossover frequency on the headunit to 40hz?

i think that setting is too low. when the CD got to 41hz the x-over on the headunit was filtering the test tone out (hence the drop in voltage).

even with a w7 you should be setting the low-pass crossover to maybe as low as 70 but no higher than 125 (probably way to high for a w7). i run my two 8's at 99 sometimes if its rock and 78 if its drum and bass.

" sine-wave test tone recorded at 0dB reference level in the frequency range to be amplified (40-50 Hz works well). "
they mean only the test tone should be around 40-50 hertz.

here is the best way to tune in my opinion
1. turn the gain on all amps as low as possible
2. turn the volume on the headunit to 90-95% of the volume level.
3. turn each amplifier gain **independently** up to the loudest possible level you can tollerate without causing distortion. mark or make a note of this level.
4. turn all amps up to the marked level
5. tweak as necessary to balance