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View Full Version : Audio Problem... Lets see if someone can explain this



bloodrose
07-20-2007, 02:03 PM
First I do have the JBL system in the car and it does work.

Ok so my wire diagram is a little crappy but it should explain what it needs to. Assuming all the other wires are hooked up properly (power, remote, ground, etc.) I'm wondering why this set up doesn't work.

My idea was to use my Pioneer Digital Signal Processor that I had sitting around, power the speakers from a better amp and still have the factory sub woofer functional. The problem I'm having with this set up is I'm not getting any sound from the sub or the speakers. If I try to hook up an individual speaker to an output on the aftermarket amp I get sound from it. But I don't get any sound when I plug in a wire harness from the amp to the existing wire harness that goes to the speakers.

Now if I were to take a direct feed from the speaker wires that come from the back of the head unit and just use a harness to connect the two plugs that normally plug into the factory amp, that works fine and I get sound and power from the head unit, but then I lose the sub and pretty much the whole point of this project with the DSP.

Can anyone explain why this setup doesn't work??? It could be something simple I'm over looking or something that I've wouldn't really even consider.

I won't be back to answer questions until later tonight, I just hope I explained myself well enough.

S_Mazza
07-20-2007, 02:42 PM
It looks like you are using a speaker-level output to the factory amp and a low-level output for the main speakers. Are you sure your headunit can do that?

Also, are you sure that the remote turn-on for the factory amp is working? If the factory amp is not powered, I don't think there will be any signal going to the factory sub amp.

auggystyle
07-24-2007, 05:07 AM
your better off just bypassing all of the stock subs and amp, its a wiring nightmare....they make wiring harness' to bypass all of that stuff...i had major problems with my stereo...i had the jbl with sub and amp...turned out it was a bad cd player that caused all of my problems...but your better off just putting new stuff in

sizemoremk
07-24-2007, 03:31 PM
I have read a few times that the factory head unit signal to the amp is between "RCA line out levels" and "speaker output" levels. So you don't want to power the factory amps with normal speaker level out of an aftermarket head unit as it is looking for lower level input. I don't know if too much voltage will put the factory amp in protection mode or screw em up or what???

On the RCA out, are you sure there isn't a setting in your stereos menu to turn the RCA on? I have a pioneer in my truck that you must specifically turn on the RCA jacks... Or maybe it won't let you use both the RCAs and the speaker outs???

S Mazza is correct, the factory amp has a remote on just like the aftermarket does. Is that still powered? I beleive that remote on does comes from the factory head unit.

Don't know if this will help or not, but I still have the factory head unit/CD setup and in the last week or so I have installed a kenwood 4 channel amp using an SLC4 Line level converter from scosche from walmart.
http://www.scosche.com/scosche_caraudio.aspx?CategoryID=229&ItemID=SLC4

Along with a metra 70-5513 amp bypass harness from Circuit city.
http://www.oem-auto-accessory.com/70_5513.html

I cut into the metra harness on the amp-in side to go into the line converter, then used the RCA outs on the line converter to go to the new amps RCA inputs. Then from the amp speaker output back into the metra harness amp-out side to go back into the factory speaker harness. Off subject but I also replaced the speakers with 4 new alpine 5x7s I got for
$80 shipped on ebay ;)

I am in the process of installing an 8" "JL Audio" subwoofer in the factory enclosure, which will be powered by an additional sub amplifier. The amp I have has 2 pairs of RCA-in jacks and an RCA-out to go to the sub amp. The JL Audio sub I used required some cutting on the factory enclosure, but the enclosure is suppose to be .37 cu ft, and the speaker called for .37 cu ft...

Maybe too much info, just something to think about...

I'm sure you've seen some of this before, but just in case, here are some useful diagrams:
http://www.35thatr.org/Radio/RadioRelatedPages.htm

You might try using a line converter and going directly into the factory subwoofer amplifier and cutting out the factory 4 speaker amp altogether... Does your DSP or amp offer a separate RCA sub output?

x182dan
07-24-2007, 10:30 PM
Don't forget the stock amps suck and they are known to fail

S_Mazza
07-25-2007, 12:58 PM
I don't really mind the stock amp, and I have never had a problem with one. However, I never really look for big power in a stereo. Also, I know that you can run the factory amp with speaker-level inputs. That is not what it is designed to do, but it works fine. My old '89 has been running that way for about 11 years. The head unit is a JVC from 1995 or so, not too powerful or fancy. The two downsides that I know of are 1) You are amplifying the signal twice, which reduces the clarity somewhat, and 2) The volume control is not as fine, as the bi-amping mean that the speakers are maxing out at maybe 1/3 of the HU's maximum output.