Lowering Gain on Front Amp vs. Sub Amp

[tracyrick 10+ year member]

So the bass output from my 12W6v2 sub is weak after setting the gains on both my amps with a DMM. Per JL, I went 31.6V for my 500/1 (sub amp, 2 ohms), 24.5V for my 300/2 (front amp, 4 ohms).

The next step is to then reduce the gain on the amp where the sound is out of balance. So that means I reduce my 300/2 gain, and just turn up the HU volume. Fronts are MB Quart QSC216 6.5" (150 max. rms).

So far I have reduced my 300/2 gain from about 55% to 25%. The bass from my 500/1 and sub sound a little louder, but not as much as I want.

My questions are:

1. Am I compromising my fronts? Will the lack of gain be reducing my SQ/dynamic range? Or does the reduced gain just make the volume lower? They still sound fine to me when I turn up the volume on the HU, but not sure if I'm missing something here by turning the gain so low.

2. How frickin' low should I go on my 300/2 gain to try and get my 500/1 and sub to sound louder?

Click to read more...

 

[helotaxi 5,000+ posts]

What level test tone did you use to set the gain, and is your meter a True RMS meter? If you used a 0dB tone, try it with a -3 or -6 dB for the sub amp. If the DMM isn't a True RMS, divide the voltage you want by 0.707 and use that voltage as your goal.

 

[Trey803 5,000+ posts]

I dont understand......turning your gains down and then turning the volume up on the HU higher is pretty much doing nothing? You want to set your volume where the nonamped rear speakers are on the verge of distortion but not there yet.....then you want to set you gains on your amp. Why did you turn the volume up more?

 

[Trey803 5,000+ posts]

I would say do some recalculation and then try it again...if thats still isnt loud enough for you set the subwoofer gains by ear until you reach the point where u can notice distortion

 

[tracyrick 10+ year member]

-3db. Not sure about the true RMS question, but I'll check.

Just redid test turning my HU's sub volume output down to 75% and sub sounds much louder. JL says you can do this, although most online guides people write say to keep that control at 100%.

Still wondering what affect reducing my gain on the fronts has on my fronts performance? Anyone know? Will be sound be less clean?

 

[Trey803 5,000+ posts]

Hu sub volume output? Can you explain what exactly that is

 

[SAG3 5,000+ posts]

Hu sub volume output? Can you explain what exactly that is

//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif Sub volume..........

 

[helotaxi 5,000+ posts]

Trey-please stop trying to "help" because you don't understand the problem or know the solution.

Whatever you set the sub level to when setting the gain, treat that as your max level from that point to avoid clipping. Same with the volume. As far as the effects of turning down the gain on the high freq amp, you will have a lower max volume and....that's it. The usable dynamic range will be reduced a bit but the actual sound of the amp won't be affected at all.