Originally Posted by Martycool007
I have read that link on the previous page about how to determine the subwoofer output voltage and the AVR's maximum clean output voltage, and I just can't follow this crap. I get so confused about half way through reading that. This really sucks because I have ADHD and it makes this stuff very hard to follow. I am honestly so frustrated.
Let me see if I got this right and if not, hopefully someone can help.
Set speakers to large.
Set AVR to stereo.
Set all speakers and subwoofers to maximum level via AVR's menu.
Disconnect all speakers
Turn volume on the AVR to maximum setting
Measure the output of the Left speaker pre-out with a multi-meter. (not sure how to do this? What am I looking for?)
The VOM meter should be set to low AC voltage.
Write down the voltage reading for future reference.
Connect pro-amp to front left speaker pre-out on the AVR.
Reconnect front left speaker to the AVR.
Play a 1khz 0dbfs test tone.
Start with the Behringer amp at the lowest gain possible that still outputs sound.
Slowly increase the volume on the AVR until you hear an overtone, then reduce the volume on the AVR until the overtone goes away.
Do not touch the volume on the AVR now.
Disconnect the Behringer pro-amp.
Now run a 60hz test tone through the AVR and take another voltage measurement from the pre-out on the AVR.
Make a note of this reading and keep the AVR's volume control the same. This reading is your AVR's usable output voltage and this particular volume is the AVR's setting that you need to use when setting the gain structure.
Is all of this correct? What do I do next to measure the sub pre-out voltage? Can a cheap Wal-Mart multi meter be used for this? That is all I have to work with at the moment. Also, any other opinions on the hum issues?
OK, lets back up and regroup for you now.
I'm not even going to address anymore why the aforementioned post is accurate, Its co-authors are well known experts(Ricci, AX9, and BruceK).
I'll try to give a cliff notes version(somebody will correct me if I mis-speak the post im sure).
Setting everyting to Max(see post) and measuring preout voltage at all max settings tells you this:
1. Your AVRs max pre out voltage for that output.
2. From that max voltage you will know if your AVR can fully drive your pro amp(see your proamp manual for input sensitivity).
Now the overtones stuff is merely clipping detection and introduction of harmonics as beast suggested. However the post says ignore that for subs and subtract ~30% from your max preout voltage
. This is your max clean avr preout voltage for the sub preout. Turn down master volume on AVR until you read your max clean
avr preout voltage(Max voltage -30%) on multimeter. Note this Maxter Volume setting.
Now(refer to post) connect amp, turn AVR master volume back to same setting you noted before and slowly turn up "gain" knob(s) on pro amp until you light the clip lights solid.
Thats it. Don't touch the gain knobs on your pro amp, it is now set to clip at the same voltage as the AVR preout. You can lower gains, trims, whatever you want in the AVR and the AVR and pro-amp will clip together at same voltage. Obviously you want to keep the clip lights out altogether during program material but thats another issue altogether.