What is wrong with my car audio system? Help!

[Kroze]

Ok here's the sound setup of my car.

MTX Thunder 4300 Amp
2 200watts Rockford Fosgate Subs
JVC Head Unit

Here's the story...

One night i have the system on too loud and when i tried to turn the volume down, i accidentally hit the 'loud' button on the head unit. What happen next started everything i've experience so far. The sound system gave a little buzzing noise and all of the lights in my car dims. I freaked and turn off the head unit. I turned it back on after a few minute and....my sound system sounds like crap. The bass kick isn't clean and as loud as before. I also notice some subs farting noises (like when the sub is blown)

- I tried replacing the Subs with the Pioneer 450watts, problem still exist.
- I checked all of the fuse and they're ok (on the amps)

Some guy at circuit city told me that it could be my head unit that's damage that's why the base kick is not as good as before but i doubt that's the problem since i'm still receiving audio signals from the unit to the Amp.

This morning, while having the engine turn off, i played a CD and to my surprise, the Subs will not work after i turn the volume up past 20 on the Head unit. Anything below 20 the subs will work fine.

In the afternoon after i got out of school, while driving, the subs works fine. I turned it up past 20 and it still works fine. I stopped the car with the engine off and turn the volume past 20 and the subs works fine except this time, it quit after going past 27.

This is making really mad cause i don't know what's the problem. I tried replacing the Amp too and it doesn't seem to work. Can someone help me

 

[Cattlegod]

sounds like you have a short somewhere.

when you turn the volume up past 20 the short is drawing too much current and tripping the breaker on the amp. check your wiring

 

[blahblah99]

I don't think its a short. Your problems came up after he accidently hit the LOUD button. You said you replaced your subs and amps and still doesn't help.


The only solution left to try is to see if your head unit is outputting the right signals. Do you have a oscope handy? If so, hook it up to your PREAMP OUT on the head unit and crank up the volume past, play a 100hz sound wave (u can make that from any sound editing software and burn it on a cd). See if its giving you a pure 100hz sine wave. If it does, connect your amp to the head unit and measure again. Is it still giving you a 100hz? If not, your head unit is messed up and the parts need to be replaced.

I'm not sure how the JVC works, but if you have 3 sets of PREAMPS out on the head unit (front, rear, and sub), then the SUB section of that head unit needs to be replaced. Its probably a blown op-amp.

 

[Kroze]

<< sounds like you have a short somewhere.

when you turn the volume up past 20 the short is drawing too much current and tripping the breaker on the amp. check your wiring >>



No I don't think it's drawing too much power because before all of this (hitting the loud button), the volume can be a lot higher and i can hear really good bass.

 

[Kroze]

<< I don't think its a short. Your problems came up after he accidently hit the LOUD button. You said you replaced your subs and amps and still doesn't help.


The only solution left to try is to see if your head unit is outputting the right signals. Do you have a oscope handy? If so, hook it up to your PREAMP OUT on the head unit and crank up the volume past, play a 100hz sound wave (u can make that from any sound editing software and burn it on a cd). See if its giving you a pure 100hz sine wave. If it does, connect your amp to the head unit and measure again. Is it still giving you a 100hz? If not, your head unit is messed up and the parts need to be replaced.

I'm not sure how the JVC works, but if you have 3 sets of PREAMPS out on the head unit (front, rear, and sub), then the SUB section of that head unit needs to be replaced. Its probably a blown op-amp. >>



My head unit output is fine before all of this (hitting the loud button), the volume can be really high and the bass kick is amazing. Is it possible to damage the head unit output by hitting the loud button?

 

[Kroze]

Oh and also, my power cable is thin as a thread...I'm not sure if it is any relavant. But it seems to work fine for me though. Should i replace the power cable?

 

[Heisenberg]

If you've replaced both the subs and the amp, the only thing left is the head unit. Try a different one and see what happens.

Edit: Double-check the wiring too just to be safe. Make sure nothing got too hot and melted or anything.