Weird Audio Problem, Help!

[GreenStangGT]

STILL have the problem!

Today I had some free time so I went ahead and re-wired the H/U in an effort to solve the problem of a possible ground loop. Unfortunately, I still have the problem.

To summarize the problem at this point:
*Started (at least I starting noticing it anyway) after amp/sub install.
*The problem only occurs when the H/U is in AUX-IN mode, not when the radio is on.
*The noise (which is especially noticeable from the small upper left/right speakers) sounds like static on the radio and gets louder as the volume increases.
*When I adjust the volume up, the sound gets momentarily louder (as if the H/U was set to beep, but it's not). This part of the equation is hard to explain, so that's the best way I can describe it.
*Occurs with or without the RCA's plugged in, as well as with the car on or off.
*When the car is on, I can hear the turn signals through my speakers.

What I've Done:
*Made sure the RCA's and power wire are run on opposite side of the car.
*Re-grounded the amp directly to the chassis.
*Re-grounded the H/U to the same place as the amp. (The problem seemed to get slightly better after this, but that make very well be only in my imagination.)

So, any further ideas? Thanks again guys!

 

[95BlueStallion]

Possibly something wrong with the H/U? Its odd that it only does it in a certain mode... A bad ground would do it in all modes I would think. Im not that smart with all this stuff, just installed many stereos and ran into that similar problem once with a bad ground, and another time with bad rca's. Try swappin in a buddy's H/U if anyone you know has another sony deck, and see if the problem persists...

 

[GreenStangGT]

Possibly something wrong with the H/U? Its odd that it only does it in a certain mode... A bad ground would do it in all modes I would think. Im not that smart with all this stuff, just installed many stereos and ran into that similar problem once with a bad ground, and another time with bad rca's. Try swappin in a buddy's H/U if anyone you know has another sony deck, and see if the problem persists...

After re-reading the article from the link above, I am thinking/hoping that the levels are wrong and what I'm hearing is what he refers to as system hiss. The link on that page that talks about system levels seems uber-complex to me though. It almost seems like it is in a foreign language; and I'm a freaking English major for God's sake!

Anybody know anything about the topic that could simplify any of it for me?

 

[GreenStangGT]

Well, the levels may indeed be part of it; I just realized that I can control the noise via the EQ controls on my H/U. If I turn the mids or high +db, the sound gets louder and works the same in reverse. Also, if I turn the AUX-IN level down, the sound decreases.

Nonetheless, the problem remains. Turning the AUX level down makes the problem better, but results in me having to turn the sound up much louder to hear it properly,... and then the noise comes back.

Any ideas?

 

[95BlueStallion]

There are high-pass and low-pass filters on your amp and in the sound menu of most H/U's. I dont know the scientific explaination of what they do, but they definitely affect the sound. Try adjusting those settings and listen to the sound difference and see if you can at least tone the noise down to the point of not being too noticable...

 

[Zero Signal]

Still, I haven't read that you've run a new, independent power wire for the deck. Do that next and make sure it's away from the other harnesses. I ran mine from the distribution block by the driver side shock tower with good success. I can't remember if it was a 10 or 12gage wire though.



Many low to mid end H/Us will have idle noise and will pick up a lot of engine noise inherently. High end units will filter that out. If you have all the wiring done properly and you are getting some noise, it sounds like it's the H/U.

It should go without saying that the system levels should be set within reasonable limits. The article mentioned 80% to max. With EQs and gains, I keep that to 50% since I really hate to hear clipping. I like the decks to have high volt pre-outs to make up for that.

I have a $120 H/U in my truck that has terrible "system hiss" as the article put it. I attribute that to it being $120. When a CD is put in, you can here it thinking through the speakers which is to be expected from a $120 deck IMO. In the Stang, I'm running an older $800 Pioneer deck and it has almost NO audible hiss or feedback. It also has 6v preouts so it takes very little gain at the amp to get it to to where I want. I usually gage it by turning it on and turning it WAY up with no signal to see what gets through. It has about as much noise as my Marantz home audio receiver (almost none).

To put that into perspective, I installed both deck with the same wiring and grounding methods.

 

[GreenStangGT]

Still, I haven't read that you've run a new, independent power wire for the deck. Do that next and make sure it's away from the other harnesses. I ran mine from the distribution block by the driver side shock tower with good success. I can't remember if it was a 10 or 12gage wire though.

This seems smart, but it makes me wonder why the problem would only present itself in the AUX mode?

 

[GreenStangGT]

Try swappin in a buddy's H/U if anyone you know has another sony deck, and see if the problem persists...

So this morning I hooked up another Sony H/U in order to see if mine was the problem. However, the new H/U I hooked up won't play! It turns on and acts as though it's playing, but no music can be heard through the speakers. I know for a fact that it is a working H/U, any idea what the issue could be? Wouldn't all the Sony decks use the same plug and should thus be plug and play?

 

[95BlueStallion]

So this morning I hooked up another Sony H/U in order to see if mine was the problem. However, the new H/U I hooked up won't play! It turns on and acts as though it's playing, but no music can be heard through the speakers. I know for a fact that it is a working H/U, any idea what the issue could be? Wouldn't all the Sony decks use the same plug and should thus be plug and play?

Again, I dont know a ton about all this, but all the sony decks that Ive played with have the same connector shape and size in the back, and have all been plug and play.