Bass goes BOOM Speakers go SILENT

**Lankin** · 08-17-2009, 02:23 AM

I have two amps in my car. One amp is a 4 channel amp that powers my 4 speakers. The other is a mono amp that powers my subs. My problem is that when I turn my volume up pretty high it will get to a point where the music from my speakers gets silenced every time the bass hits. I will still hear the bass clear and loud as ever, but the speakers will fade to almost no sound at every hit and then come back. This problem can also be replicated by having the stereo at a loud but stable level and then adjusting the bass boost up on the mono amp via the amp control to a point where it is unstable when the bass hits.

I cant tell if this is a gains/output settings issue or a power/wiring issue. I never had this problem with the same set up running off the head unit. The only change is instead of the HU providing the input to the amps, my computer is. Any help would be appreciated. Below are some additional details.

4 Channel amp
50 rms x 4 @ 4 ohms
powering 4 infinity 6 x9's that handle 50 rms

mono amp
1600 rmsx1 @ 1 ohm
powering 2 hifonics atlas that handle 800 rms each

both amps are being powered by a 4 gauge wire that runs from the battery back to a splitter and then 4 gauge wire is ran to both amps. They are both grounded in a similar way except from the ground splitter i ran 3 4 gauge wire to the same grounding point.

My sound card has two outputs. as of now i have one output being split and ran to all 4 channels of the 4 channel amp. The other output runs straight to the mono amp.

Car is a 1993 Lincoln town car

Thanks!

**mentor** · 08-17-2009, 02:33 AM

Do your headlights dim as well when the sound is cutoff? If so, try adding a capacitor to your sub amp. This will hold enough charge for peak bass hits and will avoid the issue you are experiencing.

**pancit175** · 08-17-2009, 03:00 AM

I would suggest getting a bigger power wire. Check out http://www.bcae1.com/wire.htm. 4 gauge wire is only capable of transferring about 1000 watts from the battery. The sub amp is capitalizing on all of the power the power wire is capable of transmitting. If what you are saying about your RMS wattage of your amps are correct then you would need at the very least 2 gauge wire to get the appropriate power through the wire.
The link http://www.bcae1.com/images/swfs/sys...nassistant.swf says that you would need at least 1 gauge wire.

**Lankin** · 08-17-2009, 08:32 AM

I already have a 1 fared capacitor in the setup. The Idea of needing a larger power wire did cross my mind before but I just was not sure. I think I will try that, because that seems like the most logical thing to do.

**Sonicxtacy02** · 08-17-2009, 09:02 AM

definitely get a higher gauge power wire. But sometimes thats a sign the battery or alternator is the culprit

**Lankin** · 08-17-2009, 09:15 AM

That is definitely something that I fear. I am pretty sure the stock altertnator only puts out 95 amps which technically is not enough to power everything that I have in my car. As of right now I am hardset on upgrading the power wire.

2 questions:

Would another run of 4 gauge wire right along with the first one do the trick?
or is there something technically wrong with that?

What kind of tests would I run to find out if the battery is the problem?

**digital79** · 08-17-2009, 10:05 AM

Your alternator puts out only 95A, and you need more or less 160A just for the audio when at max RMS (RMS totalled, 70% efficiency).

1) Get a deep cycle battery
2) Upgrade wiring to gauge 2 or even 0

What's probably happening, is that there's a serious voltage drop when the bass hits, and the smaller amp shuts down when it senses low voltage condition.

**DarquePervert** · 08-17-2009, 10:38 AM

Originally Posted by Lankin

That is definitely something that I fear. I am pretty sure the stock altertnator only puts out 95 amps which technically is not enough to power everything that I have in my car. As of right now I am hardset on upgrading the power wire.

2 questions:

Would another run of 4 gauge wire right along with the first one do the trick?
or is there something technically wrong with that?

Yes.
Your sub amp by itself pushes more than the rated capacity of 4awg wire.
You're risking more than just your audio cutting out. You're risking overloading that wire, melting the insulation, shorting out the circuit and causing a fire.

Cue the infamous "Toaster Drawing".

What kind of tests would I run to find out if the battery is the problem?

You can get your battery tested for free at just about any auto parts store or garage.

However, I'd get that power line replaced before doing anything else.
You should also update the ground line from battery to chassis with the same AWG as the power line. The current may flow through the power line just fine, but if it bottlenecks at the ground, then you will still have problems.

Question... Where's the PC in all this?

**Lankin** · 08-17-2009, 11:03 AM

Thanks for all the information everyone.

The PC comes off the same block as the amps. it uses an m2-atx 160 watt powers supply. I am using 10 gauge wire on that. You guys all have me completely convinced that I need to upgrade this power wire. Luckily I literally just got done the install yesterday so I doubt I have done any damage yet.

So let me get this straight though. You are saying that I can I double up 4 gauge wire from the battery back to the dist. block in order to increase power? there wont be any issues with doing that as opposed to adding a single 2 or 0 gauge wire?

**pancit175** · 08-17-2009, 03:11 PM

Doubling up on a 4 gauge wire will actually equate to a 1 gauge wire, and don't forget to upgrade the battery's ground cable as well like DP suggested.