Ok
So as mentioned several months ago I decided to gut the stock stereo system in my TSX and upgrade everything. I did the entire install myself as most car audio shops wanted 1k+ for labor however I have a few gremlins I have not figured out. First let me give you the initial setup.
- Alpine head unit on a dedicated power and ground wire to the Battery. At first I used a common ground but Alpine states you should use a dedicated ground thus I went ahead and installed one.
- Flowing from the Alpine is a mid-range quality set of Street wires RCA connectors that run down the center of the interior to the trunk and connected to a PG XENON 100.4 amp that is mounted on plexy glass in the spare tire well. This amp is grounded to the Chassy and the cable is < 12 inches long.
- Powering the amp is a 4awg Streewires cable that runs along the drivers side of the car and does not interact with the RCA's however it does cross over the antenna wire. (no way around that unless I put it under the car).
- Connecting the amp to the speakers is a mid-grade set of Monsercables that I bought on clearance and they run up the center as well next to the RCA's to the front speakers.
- The speakers have two crossovers that were originally mounted behind the HU under the stock radio however this caused allot of electrical noise thus this last weekend I moved them. One is now under the glove box and the second is mounted on the black cover under the drivers dash with the white cotton padding.

That being said, I am still experiencing feedback from the front speakers and I am not sure where it is coming from. What I have noticed is that this feed back occurs even with the radio and amp turned off. It is very suttle and does include alternator whine if I step on the gas but I have also noticed that even if I turn the car off the noise persists for about 5-10 seconds at which time I hear a relay or solenoid click from the center console and the feed back stops. I am unsure what remains powered on in the TSX after the ignition is shut off but maybe the ABS system is holding a charge?
Right now my front speaker wires flow from the trunk to the dash and than Y-out to the left/right sides, should I try Y-ing them out at say the center console and running them under the passenger foot pan?
Any ideas you have I would love to hear as I would love to fix this over the weekend.

 

If you are getting electrical noise (it''s not feedback, actually, that's something else) out of your tweeters with the system off, either:

1) You are not turning the amp off properly with the correct remote turn on wire, or

2) Your passive xovers are STILL picking up noise.

I suspect #2, but you need to be very clear that it's not #1 first, so you don't waste your time. Easy to check - does the LED go off as soon as the HU does?

Both of my passive xovers are below the glove box, but mine are actually below the carpet against the sloping firewall. You have to pull the running board and the kick and the black panel to pull the carpet back. I have not had any noise issues with them after having three sets of different speaks and passives in there, so I think it's a good place to put them.

If the amp turns off when the HU does, then none of your RCA cables are part of the problem. BTW, what brand your cables are is far less relevant than what kind they are. They should all be twisted pair for maximum noise rejection, and after that, it's all personal pref, as far as noise rejection goes. You can make a set of twisted pair using household doorbell wiring with no shield at all, and it won't pick up any noise - twisted pair just doesn't pick up noise. Also, running wires at 90 degrees is not a problem for noise pickup, as inductance of noise at these frequencies happens with some parallel wires for a few inches or more.

If the amp is off, then I suspect the driver's side tweeter more than the passenger, in that I bet it's louder - although the pass might be picking up the fan motor.

Unfortunately, you probably need to move the xovers again to see if this solves the problem. I would get some lengths of speaker wire and test-locate 1 xover out of its current location, and unplug the other tweeter, and see if the noise goes away when the xover is floating in midair in your hand, for example.

This does not mean that afterwards, you won't have some engine-alternator noise - but that's not the same thing, and you need to solve this problem first. If you do have noise afterwards only with the system on, then it's a ground-loop thing on the signal wires, and the gain settings, not the speaker crossovers.

Good professional installation has a value, now, doesn't it? : )

 

Thanks for the quick post. I have validated that it is not the AMP as I have tried pulling the fuse for the amp so there would be no power.
I like your idea of putting the cross overs in the floor pan, how big are your cross overs? I am running Diamond Aud's right now and the cross overs are very large about the 6"X4"X1.5", think they would still fit there?
I am using twisted pair RCA's, I learned that lesson a long time ago in my Accord. I only referenced the brand name as I did not want people telling me I bought crap wires. I spend almost $80 bucks on the wires alone as they are just as important as the HU, Amp, or speakers.

Professonal instalation does definatly have its place howerver at the time, no dealer in the seattle area had ever done a TSX thus the 1k estimate was only a ballpark figure they would give me. I enjoy doing this stuff and I could not have afforded to pay someone to do this as I also gutted the entire interior and dynomated the floor, doors, and trunk.. I will try moving the corss overs this weekend as I am becomming a pro at taking stuff apart. I have some time to kill as my PG amp cooked itsself the other day as I was driving. It will take them 2 weeks to send a replacement so I have some time.
Thanks for the advise though, it give me a good starting place.

 

Oh yea, I will be in portland in the next few weeks, where is your shop, do you have a website.

 

See? People will still tell you that - just can't worry about what people tell ya

BTW, $80 in RCA cables isn't too much in the scheme of. Google MIT Terminator.

avincar.com is the website, feel free to come by and listen to the demo TSX! We are not here Sundays, thoough - FYI.

The original xovers were the ones that came with the Alpine SPX-F13M kit (now discontinued). In 19 years in consumer electronics, they were the largest passive xovers I've ever seen. I've seen 3-way passives that weren't this big. I actually lost almost 2 inches of legroom by putting them there because they essentially raised the floor by that much. (My DLS xovers are now MUCH smaller.)

Good luck and let us know how it sounds!