Are my amps underpowered? (car audio)

matt tibbetts

Freshman
Jul 9, 2013
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I just bought two 1100 watt crunch amps. Each amp is powering it's own 12" sub. Each amp has it's own 4 gauge wire with a sixty amp fuse powering it both coming strait from the battery. The grounds are also four gauge and are connected to the body. My problem is that when both amps are connected and running the subs sound terrible. They a quiet and don't sound deep or good at all. But if you disconnect the RCA from one amp the other sub sounds great it's loud. Its as if there is not enough power for both amps and only one amp can be powered effectively. What can I do to make both amps run at full power so both subs sound good?
 
Re: Are my amps underpowered?

One of the speakers is wired with the plus and minus reversed.

This is not a car audio forum.

Mac
 
Re: Are my amps underpowered?

First of all, make sure the polarity on one of your subs isn't inverted. The symptom you describe actually fits with your subs being opposite phase.

To increase available power; Put in an extra battery.
Battery voltage drops quite rapidly once you pull more than 30 amps from a regular battery, and only way to have stable power is bigger/more batteries.

Installing reservoir caps will also help.
 
Re: Are my amps underpowered?

Sorry this was just the first forum I found....but I did check the polarity on both amps to both subs and they are correct
 
Re: Are my amps underpowered?

Sorry this was just the first forum I found....but I did check the polarity on both amps to both subs and they are correct
I would DOUBLE check-and then I would flip the polarity on ONE of the subs to see what happens. It will get louder or quieter. You want louder.

I highly doubt it is a power supply issue. Because if you were having loss across the power cable-when you turn on the second sub it should be at least as loud as the first one.

Maybe the polarity reversal is somewhere else-inside the cabinet for example.
 
Re: Are my amps underpowered?

Although as others have pointed out your problem is likely a polarity swap somewhere (speakers can be wired wrong from the factory, check with a 9 volt battery that they both "pop" in the same direction), it should be pointed out that at 12.6 volts, even if the amps are 100% efficient, the peak draw is 175 amps, 10 times what it would be with household 120 volt power.

A single car battery won't provide that amount of amperage for long unless the alternator also can keep up to the demand.
 
Re: Are my amps underpowered?

A single car battery won't provide that amount of amperage for long unless the alternator also can keep up to the demand.

+1, and that is on top of powering the standard auto accessories. I was into the Car Audio craze when I was a teenager, all the guys with serious ambitions (and cash) ran a second alternator, battery and some power caps to keep the juice coming to their system.
 
Re: Are my amps underpowered?

Just wondering what the exact amplifier model number is?
There you go wanting specifics. Why don't you just give an answer he wants to hear-------------------------- ;) ;) ;)

As typical people want simple answers for questions that they don't provide enough information Like EXACTLY what is the wiring-etc

I have some some high quality professional drivers that have the + and - terminal colors reversed-actually a couple of times. So it might "look" like it is wired properly-but in reality the drivers could be out of polarity-HIGHLY likely.
 
Re: Are my amps underpowered?

There you go wanting specifics. Why don't you just give an answer he wants to hear-------------------------- ;) ;) ;)

As typical people want simple answers for questions that they don't provide enough information Like EXACTLY what is the wiring-etc

I have some some high quality professional drivers that have the + and - terminal colors reversed-actually a couple of times. So it might "look" like it is wired properly-but in reality the drivers could be out of polarity-HIGHLY likely.

I know, was just wondering what amp he has. The power is fine, even on 1 battery. Its clear its not a power supply issue, but out of phase issue. Done the car audio thing many years ago also.
 
Re: Are my amps underpowered?

Running the negative back to the battery is also a good thing. There may be impedance in the chassis connections.


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I still argue that it is NOT a power cable or battery type issue.

If that was the limiting factor-when the second speaker was turned on-then the output should be equal (will little or no additional output-although you could argue that the extra cone area would increase the output even if the total input power stayed the same)-NOT decrease.

The only explanation (that I can think of) is a speaker polarity flip somewhere-could be anywhere.