crossover on amp and other ?’s

What's up guys. I have a few questions that i'm hoping some of you can answer for me.

My friend who works at a shop locally here totally rewired my system for me at no charge because he enjoys doing it for his close friends.

Let me really quickly describe my system. As for the power, I have a 1 gauge power cable ran to 2 caps, 1 gauge from there running to a distribution block, then from there, 3 seperate 8 gauge wire ran to each of the 3 amps, that each drive a 15" W3v2.

As for the RCA part, I have the LPF preout from the deck running into a Audio Control 24xs, then the LPF from that to a Audio Control Matrix Line driver, that splits out 3 pairs of RCA's to each of the amps

Now for my question, the bass before he rewired everything was fine. After he rewired it, it seems a little muddy and lower volume. I was looking at the LPF crossover on the amp, and it goes from 50 to 200 Mhz. He has it set in the middle. How generally should the crossover be set on the amp?. Same with the gain, it's set at exactly the middle. But for some reason, i'm lacking bass. Originally, each amp was bridged and ran in mono to each sub, but he switched the speaker wire to run out of the left channel, and set the amp to stereo. What is the purpose of that?. He claimed the amps can not handle a 2 ohm load when bridged (which I know, because I contacted Kenwood), but can when wired in stereo. Is that true?. My friend isn't a fly by night installer, he's been doing this for years, and is very respected in our area. But, I was just curious if that was the case. Also originally, all my wire from the cap and beyond was 4 gauge, and he switched it to all 8 gauge. The amps are rated at about 450 or so RMS, but 1,000 peak, even though I feel that # is inflated. But does everything I just mentioned that he did sound justified?. Also, how in fact should the crossover and gain be set if I want maximum bass?.

Second part of my question is regarding power issues. After playing my setup for 30 mins or so, my battery light on my dash starts to blink. Does that mean the alternator can not keep up with the current?. I have a yellow top battery, but still the stock alt. Should I upgrade my alt, and if so, what generally do most people get as far as amps?. I am just assuming that since my battery light is blinking after about 30 mins of use, that that's what is. I might be wrong.

I hope someone can answer my questions!

Thanks guys!.

1.  Post the model # and specs for the amps.  Currently, it appears that the output is 1 X __@ 2 ohm stereo for each amp.

2.  Are the subwoofers D2 or D4?

3.  And are both audio control units situated close to the head unit?

model # is KAC 929, and specs are as follows..

Subs are D4

And the audio control units are no where near the deck, they are mounted to the box.

A crossover point of 125 is to high for 15's.  You might use a high crossover point on 8's to increase their response, filling in the sound a bit, but not a 15.  Your getting less power because the amp is no longer bridged (I think, if i understand your correctly).  It is running stereo, with one channel to each voice coil.  It would be better for your amp this way because each of your voice coils are 4ohm (making an assumption) and is a stable load on the amplifier (your amp should not get as hot now).  Your getting less sound because your delivering less then half the watts you were before.  Bridged, your output doubles at 4 ohms. But you were at 2ohms, so it should double again.  Being that your amp is not stable 2ohm bridged, we can assume you are running just above your stated 4 ohm bridged RMS.  Your gains can vary.  Different amps have different sensitivity.  So if you take 3 different amps(same wattage) and put the same signal to them, you most likely would have to set the gains in three different places to achieve the same amount of output.  Also, decks put out different amounts of voltage.  So lets assume my old Pioneer puts out .5v and i have my amps set up for it.  I get happy and buy a new headunit.  The new head unit puts out 4v of preamp power.  I install it and I can barely get the volume up before it is cranking as loud as the pioneer!  Well its not that the deck is better, just that the amps are set to be very sensitive to accommodate the old pioneer.  So i would have to go and turn the gain DOWN to accommodate the new headunit.  In short, there is no perfect spot to set the gains.  I personally: 1. do a little listening to the components(sub off)  to set the EQ (bass and treble, loudness off), when i feel i have achieved a good sound   2. turn the gains all the way down on my amps  3. turn my deck all the way up  4.  turn up the amp gains on the components until they just start to distort, back them off just a tad.  5. bring the bass, turn the sub amp on and turn up the gain until i feel i have achieve balance.  Your crossovers will vary depending on your speaker size.  Some people say that you should not turn your deck all the way up to set, but i do because 1. i don’t use deck power  2. people want to get in your car and CRANK it until they hear speakers popping.  This way, the volume is maxed and they assume it cannot get any louder.  I have people say, "that’s as loud as it goes?   you dont have enough power to pop the speakers? how do you know they cannot go louder?  my friend can make his speaker pop, he's got major power."  Yeah, yeah, good for him.  Blah.

sounds like you need a new alternator, if you are running 3 or more amps, it would be a good idea to get one...

As far as your bass sounding muddy,, you have 15s, i normally set the crossover no higher than 50hz for 15s...

(...to heavilymedicate-you need to start writing in paragraphs, interesting stuff to say but it is just impossible to read that much without breaks...)

To the subject:  You can do a few different things with your system.  Marshalltown is right in that you are using more power from the car than what you are ending up showing.  Three stereo amps will necessitate a HO alt.  You could trade out the amps for three mono amps capable of a two ohm load and use half the power, and might not need to upgrade the alt.

Second possibility, is to trade out the D4 subs for D2's and use the amps you have now.  This will also mean you upgrade the alt.  But to get the most with what you have now, you should rewire the subs to series for 8 ohms each and bridge them to each amp.  You'll then get 300 watts each instead of the 230 each are getting now.  And you'll be using both channels.  Right now they are one-channel driven.

Third, the Audio Control Matrix line driver should be connected near the head unit to get the maximum benefit of its use.  Manual is here.

Thanks for the responses guys.

The idea of one amp to run all 3 of my subs doesnt sound like a bad idea. It seems that my current set-up now isn't even half the power my subs can handle, am I correct with that?. I would assume going with a class d amp, that my subs would probably sound 50% louder.

Say I go with the majority here and do in fact trade in my 3 amps, for 1. What would be a good choice of amp for the maximum bass possible that my subs can handle?. Again, I have 3 JL 15's W3V2's, dual 4ohms in a sealed chambered box.

Wouldn't I need a pretty large amp to run 3 of these subs?.

Money isn't too much of an issue, so I would like suggestions on some higher end amps if all possible.

Thanks again for all the help you guys are giving me.