Hey I just had a shop install my speaker and subwoofer amps in my car. I took a look at the gains and the subwoofer amp gain is all the way up and the speaker amp gain is pretty much all the way down. Does this sound right? I thought turning the gain up all the way is bad for the amp, and turning it all way the way basically makes the amp useless..

Oh and what should I set the crossover points at on both amps? I read that 80hz is good for the sub amp, what about the speaker amp?

I'm using an alpine f300 for ppi 356cs speakers and an alpine m450 for a 10'' alpine type r.

The shop has really good reputation so I don't think they'd mess up something like this. Before I try to retune it myself I thought I'd read what some of you guys think.

 

The gain level depends on the speakers, HU, and amp. While there are general rules of thumb, there aren't any real set-in-stone rules.

Here's the best way to adjust:

Using a CD of your favorite band/song (NOT a CD made from an mp3, but a full CD), turn all the gains down.

Set the HU volume to approx 75/80% of max.

Running passive (2 chan):

Start with the door speaker gain, adjust it up till either A) the music begins clipping/distorting or B) it's as loud as you'll ever want it - whichever comes first. If you reach the clipping/distortion level first, turn the gain back approx 1/8 turn (this will differ based on amp - but definitely turn the gain back till there's no distortion/clipping at all).



If you're running active (4 chan):

Set your tweeters first via the same procedure as above. Note where the gain knob is set then turn it all the way down again. Move to the door woofer gain and adjust it the same way only leaving the gain at it's set point. Move back to the tweeter gain and turn back to your desired set point.

The next step is somewhat difficult, relatively subjective, and can take quite a bit of tweaking to get right.

Turn the tweeter gain back to your previously noted setpoint. Now, listen for at least a minute, determine if there's too much bass or treble and adjust the relative gains accordingly (always looking to turn down the overwhelming factor). This sets your staging. Properly staged, the sound from the woofers and tweeters should meld cleanly. The goal is to hear the music, not the speaker (if that makes sense).


Whether running active or passive, the final gain to set is the subwoofer. Note the position(s) of the above set gain level(s) and turn it/them all the way down.

Adjust your subwoofer gain the same way you initially set the other gains. Now, move back to the door amp, adjust the gains back to their final set point. Again, listen for too much bass, etc and adjust the gains as necessary to set a proper sound stage. Remember, again, we are trying to hear the music, not the speaker.

 

Thanks.
75 percent of max volume is REALLY loud though..
I think my headunit goes up to 50, and 20 is already very very loud.
Should I just put it at 75 percent anyways, for the sake of tuning?

Also, should my headunit volume be at 75 percent also when setting gains for subwoofer amp?

And what should I set my amp LPG and hpf to?

 

Your HU should be at 75% while tuning all of the above.

Nothing says you'll run your HU at 75% all the time, this is just for tuning. In fact, if it's already "too" loud at 20, tuning this way will probably make it less loud at 20 - thus giving you more range on your volume knob

Are you running active or passive?

Your sub amp should have the LPF set at, or around, 100Hz and the subsonic filter (if there is one) set to about 60Hz.

 

are you sure that the gain on both amps are turned to 8V before you adjust the volume?

What hu are you using?

 

Alpine 9886

 

ok... i think i know why now...

1. Your amp is probably bridged for your speakers, and that means you are shooting 150W rms to a set of speakers that are rated at 60W rms

2. Your HU is a 4V pre-out model, so your correct gain setting should be around minimum for F300 and M450

3. Is your Subwoofer output volume on the HU set at +12 or higher? If not, turn down the gain on your sub amp and raise the Sub output to at least +12 before you adjust the sub amp.