Audio Gremlins?

[rallyben]

ok so I have my setup and for the last 2 or 3 months I've been having an issue. I made a switch to turn on my stereo without wiring it to the ignition so I can play it with the keys out(info). When I turn the stereo on, it loads and does its thing and then the cd starts to play. Within about a second, the speakers make a couple popping sounds and then the cd continues playing. Now I think my head unit has been tempramental and causing this. Also, my sub does not always play at the right volume. Most of the time, you can barely hear it or it just doesn't work. When I wired the car up, I used the rear channels on the head unit for the rear speakers and used the front and rear RCAs for the front speakers and bridged sub through the amp. Occasionally, my stereo works great but most of the time, you can almost never hear the sub. I have a deep start marine 668 cca battery that has plenty of power. My system does this popping thing every time I turn it on and may times while changing songs, pausing, or messing with the EQ. I know it's not normal because it used to work fine. I don't know a heck of a lot about car stereos but I think it may be one of four things or maybe all of them.

1. Head unit is fried somehow

2. Faulty amplifier

3. the gauge wire for the amp is too small

4. my alternator doesn't have enough power

For better diagnostic reference, this happens more often when the car is running, but it doesn't matter what the engine RPM is. Most of the time, when the car is off, everything runs normal, but it still pops between songs or starting up, most of the time. The sub still turns off or never comes on every once in a while even when the car is off.

One other note, when I pause the head unit, it makes a random crackling kind of noise that has not pattern whatsoever.

I did the entire install on my own, so that may very well be the problem but I'm hoping it's something that I didn't do.

Click to read more...

 

[TeenWolf 10+ year member]

That was a lot to digest!

Are you experiencing distortion in all your speakers or just some?

Does your sub amp turn off completely or is the decibel level just lowering?

 

[stones 10+ year member]

When the amp is turned on and a signal is suddenly sent to its RCA inputs a pop will be heard. The remote output on your hu is designed to turn your amps on in sinc with when the RCA outputs turn on to stop pops from happening.

Its the direct switch that you are using to turn on your amps that is the problem.

If you turn your amps on after the Head unit is powered up this should fix the proplem.

as for the intermitent sub, explain how the RCA's are run a little better.

"Most of the time, you can barely hear it or it just doesn't work. When I wired the car up, I used the rear channels on the head unit for the rear speakers and used the front and rear RCAs for the front speakers and bridged sub through the amp. Occasionally, my stereo works great but most of the time, you can almost never hear the sub"

Im confused.

 

[fatryan 5,000+ posts]

could also be that V is too low. what amp?

 

[stones 10+ year member]

'88 Suzuki Samurai

Panasonic CQ-C1300U

Alpine MPR-F240

2 6.5" Rampage 3-ways

2 5.25" Yukon Special* 2-way

Custom Box with a 8" Yukon special* Sub

Geeze thats ghetto.

 

[rallyben]

That was a lot to digest!
Are you experiencing distortion in all your speakers or just some?

Does your sub amp turn off completely or is the decibel level just lowering?

The crackling sound happens I believe in the back speakers. Those are wired directly to the internal amp inside the head unit. As for the sub, again, I'm not absolutely positive, but I don't think it turns completely off, and sometimes, I hear it just a tad but mostly not at all.

 

[fatryan 5,000+ posts]

your amp probably shuts off cause V is too low (for sub)

 

[rallyben]

When the amp is turned on and a signal is suddenly sent to its RCA inputs a pop will be heard. The remote output on your hu is designed to turn your amps on in sinc with when the RCA outputs turn on to stop pops from happening.Its the direct switch that you are using to turn on your amps that is the problem.

If you turn your amps on after the Head unit is powered up this should fix the proplem.

as for the intermitent sub, explain how the RCA's are run a little better.

"Most of the time, you can barely hear it or it just doesn't work. When I wired the car up, I used the rear channels on the head unit for the rear speakers and used the front and rear RCAs for the front speakers and bridged sub through the amp. Occasionally, my stereo works great but most of the time, you can almost never hear the sub"

Im confused.

The switch I have is set up before the head unit. It is connected directly to the battery through the fuse box and the amp is then turned on through the head unit. I know about the head unit turning on the amp, but that's not the popping sound I hear. There is more than one pop most of the time, and it's usually 3 to 5 pops before the speakers kick in. The front speakers always kick in, but it's the sub that has been tempramental.

The wiring looks like this:

-rear speakers are wired only to internal amp on the head unit

-front speakers are RCA'd only from the head unit to the first two channels on the amp and then to the speakers

-sub is RCA'd only from the head unit to the 3rd and 4th channels then bridged together (positive from channel 3, negative from channel 4) to give it double the power

One thing about the fuse box is that I am going through the headlight slots to power the amp and head unit. I know it's a bit redneck and non-professional, but how much of a difference does it make? I could just drill a hole in the firewall and run a power cable directly off the battery if necessary.

 

[rallyben]

your amp probably shuts off cause V is too low (for sub)

The amp I am using is an Apline MPR-F240 4 channel amp. I'm running an 8-gauge wire directly from the positive battery terminal to the power in on the amp. I'm running a little 12v fan off the terminals on the amp to help cool it down because this amp likes to get pretty warm under my seat.

Like I said before, a couple months ago the system was running fine, but recently, sound quality has ****** so much because of the lack of a sub, it hurts my brain. Thanks for all the help so far.

 

[fatryan 5,000+ posts]

The amp I am using is an Apline MPR-F240 4 channel amp. I'm running an 8-gauge wire directly from the positive battery terminal to the power in on the amp. I'm running a little 12v fan off the terminals on the amp to help cool it down because this amp likes to get pretty warm under my seat.
Like I said before, a couple months ago the system was running fine, but recently, sound quality has ****** so much because of the lack of a sub, it hurts my brain. Thanks for all the help so far.

the lack of SQ is probably cause of what your running...lol. does the sub cut out only when car ISNT running? have you checked to see if the sub amp is turning off, or is it just the sub?

 

[rallyben]

the lack of SQ is probably cause of what your running...lol. does the sub cut out only when car ISNT running? have you checked to see if the sub amp is turning off, or is it just the sub?

The sub cuts out whether or not the car is running, but is more prone to cut out when the car is running.

My front speakers are also connected to the amp, which would mean that when only the sub cuts out, the amp is still on, correct? If so, that's the case is that only the sub cuts out. I have had no problems with the front speakers. Refer to one of my previous posts for the wiring schematics

 

[fatryan 5,000+ posts]

The sub cuts out whether or not the car is running, but is more prone to cut out when the car is running.
My front speakers are also connected to the amp, which would mean that when only the sub cuts out, the amp is still on, correct? If so, that's the case is that only the sub cuts out. I have had no problems with the front speakers. Refer to one of my previous posts for the wiring schematics

first, check connections. if everything ok, get a new sub. chances are that cheap GM sub has kicked the bucket. get a REAL sub

 

[rallyben]

I'll try my brother's JL 10w3 with custom box out, to see if that makes a difference. I've checked the connections before, and them seem to be pretty solid.

 

[fatryan 5,000+ posts]

its also possible that your rear channels on your amp are bad or that you got bad RCAs or the LPF (if you have 1) isnt set. BUT im willing to bet big $$$ that its cause you have a shitty sub

 

[TeenWolf 10+ year member]

Let’s see if I have this straight...

Front speakers: Hooked up to 2 channels on your 4 channel amp

Rear speakers: Hooked up to HU

Sub: Hooked up to other 2 channels on your 4 channel amp (bridged)

Front speakers have no distortion.

Rear speakers have distortion.

Sub is f*ked.

Man...If this is right, then it sounds like a tangle!

You said that your front speakers are not cutting out, which means the amp is not shutting off. Maybe I'm wrong, but if the amp isn't getting enough voltage, then you would have problems with the front speakers too. Is it possible to have a 4 ch amp that only has some of the channels bad? If not, then the amp isn't the problem. It is possible that the sub is bad too.

The rear speakers off the HU are producing distortion, which would have nothing to do with the amp. You say that you hear noise between tunes, but the distortion is probably there all the time...the music just drowns it out and you only hear it during "quiet time".

I'm leaning towards a HU problem. I have a problem with the decibel level on my sub and I'm pretty sure it's a bad pre-out. Your HU could have a good pre-out for the front speakers and a bad pre-out for the sub. And the HU internal amp could be faulty too. Could be wiring, but you said that was all solid.

Whatever the problem is, you have a lot of trial and error ahead of you. Good luck!