engine47

I saw this posted today in the TSX Pre-amp out thread:

crackle and distortion from speakers

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Could anyone tell me what could be the problem if my speakers starts to crackle and distort really bad when I turn up the volume even for a little bit? It seems what there is a short or loose connection somewhere but I can't seem to pinpoint the problem. I have spend +5 hrs diagnosing the problem with a multimeter and still no progress. I have also noticed that there is a lot more static in the car now like getting shock everytime I step out of the car. Also, when I flip the door locking switch there would be instant overpowering crackling distortion coming out of the speakers. My current setup is infinity reference speakers all around, JL 300/4, 250/1, 12W3v2, and pioneer equalizer.

My guess is grounding and power line problem, but I have already double checked.
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I am having the same problem! I haven't tried flipping the door switch, and actually only tried 1 pre-amp out so far (off of the front left audio unit wires), but I have the same results, very distorted, even at low volumes. If I disconnect everything going to my aftermarket amp and re-connect the factory amp, everything is fine. So there isn't anything wrong with the factory wiring or the speakers.

To those who have successfully done this, besides connecting the "audio unit" wires, remote on wire and speaker wires, is there anything else that needs to be done? Maybe with the ground wires?

Sniff, are you by any chance using a Pioneer EQ-6500? That is the EQ I am using...I wonder if it is a problem with the EQ??? Have you tried going directly to an amp with the RCA, bypassing the EQ? I haven't been able to try that yet.

HELP!!! Can't take the stock stereo anymore!!!!

elduderino

What year TSX do you have?

Did you change Pin 7 to 11 as the later posts corrected?

engine47

It's a 2004 TSX

Yes, I switched pin 7 to 11. Found that before I started tappin into wires.

elduderino

Froma t-shooting point of view, first off I would suggest not assuming that you two have the same problem. Just focus on the problem you have. You connected ONE preamp out and it sounded bad. You connected it to a Pioneer EQ and then to an amp... right? Can you tell us what equipment you are working with?

As you have noted, your first step is to bypass this EQ and go straight to the amp. If that has the same problem, then connect an iPod or Discman with a mini-HP-to-RCA adapter into the amp and see how that sounds.

CJams

If you only connected 1 rca you may get some noise. I would try changing at least 2 like the front 2 and connect them both to the amp. as a set.

It might be the pioneer eq. I don't think the HU output line is super stable. I am still having a minor hiss problem with mine. I think the input signal to the amp isn't getting filtered well enough on mine. Currently looking for an EQ with agood input filter.

Try connecting as a pair, it could help.

elduderino

CJ, I'm not sure what you're talking about. Connecting only one RCA has never led to noise in my experience (unless not all yuour channels have a signal ground connection...)

Is your hiss constant with engine on or off? If it is, I can tell you that it's not the HU design - with a 0 bit test CD I get no background hiss out of mine at full volume. I think it's a gain thing.

What kind of filtering do you mean? Input noise rejection isn't really filtering per se... but the design of the signal input on different amps does seem to vary a bit with the TSX HU output.

I still would recommend grabbing the OEM amp ground and running a wire back to the amp ground as a test if you have engine noise issues. Hell, I'd probably grab the HU ground off the back of the wiring harness and run IT to the amp ground.

CJams

This is what I meant.....I think the input signal to my amp may be the problem. The gain is set at less than 50%. I might have to split my speakers and run 8-10channels with an extra 4 channel amp.

I did this. The noise was/is there whether the car is on or off. When I connected the HU ground to the amp ground it made the noise worse when the car was on. I also ran another RCA jack from the amp to the head unit to eliminate any chances that the rca's ran buy something else that may cause the problem. that didn't seem to do anything.

I have narrowed down to either the amp input signal needs to be filtered better or the load is a little heavy for this set up.

quantmonkey

Perhaps the static eleectricity is building up from a weak ground connection?

elduderino

I don't think the signal to noise ration of the amp gets THAT much worse with the "2-ohm" load (I'd still like to hear exactly what your speaker complement is : )

I think that if the hiss is always there with the car on or off you either have a component in their with a cruddy noise floor (Pioneer EQ? Those ALWAYS suck for noise floor IME) or the gain structure is outta whack or both.

Do you have a test disc with 0 bits? That's a decent way to start attacking the gain structure for this problem, methinks. I think you can buy some from Autosound2000.

engine47

Finally had some time to do more testing today, I found some very interesting things with this.

Test One, bypassing the pioneer EQ: I bought a female RCA coupler and went straight to the amp with the RCA, bypassing the eq completely. Now it sounds fine. Start up the car, still sounds fine.

Test two, move the eq to the back of the car. Next, I tried moving the eq to the back of the car and reconnecting it, went back to sounding like crap.

Test three, grounding the oem ground wires to the same ground in the back of the car. Next I tried grounding all of the oem amp ground wires at the same ground point, still no change. In addition, I grounded the back of the eq to the same main ground in the back, nada.

Test four, hook up an aftermarket stereo and connect the eq to it. Finally, I took an aftermarket pioneer stereo I had and hooked up enough wires to get power to it, and hooked IT up to the eq. Now, for whatever reason, it sounds great!

Results: If I go through the factory stereo right to the aftermarket amp, it sounds fine, and if I hook up an aftermarket stereo and use the eq, it sounds fine, but if I try to use the eq between the factory stereo and the aftermarket amp it doesn't work. The RCA connection on the back of the stereo has to be good because it works when connected directly to the aftermarket amp, and the EQ is good because it works with the aftermarket stereo. So what in the world can be wrong with this?

elduderino

It sounds as if either the input impedance of the Pioneer EQ is a poor match for the output impedance of the OEM HU (another way to say that is that the Pioneer EQ is less tolerant of the OEM HU output impedance than the amp is), or there is a gain/sensitivity mismatch. The only difference is that the latter can be addressed but the former really can't.

Because you have constant hiss rather than varying alternator whine, I would not expect grounding would affect your situation.

Does the Pioneer EQ in question have input sensitivity adjustments? I can't find a manual for one with Google or on the Pioneer site, but the Pioneer specs on the site do not list any input sensitivity adjustment.

Any device connected to the OEM HU ought to have such an adjustment.

Rather than try to fix a gain mismatch with an outboard line driver, I'd rather lose the EQ. It's not a very good sounding EQ in the overall scheme of things. If you were bound and determined to get a good sounding EQ, a Zapco or Arc Audio 1/2 DIN would sound much better and they have input sensitivity adjustments. There are also a number of trunk mount EQs that tend to have better design and parts used than the indash EQs. I know one forum member runs an Audio Control EQ and has no such issues.

And, of course, in one school of thought, an EQ should literally be the LAST thing you add to your system - if there's no other way to get the sound you want by simply buying speakers whose sound you like.

Sorry that I couldn't be more help.

engine47

Elduderino, just out of curiosity, do you think if I wired in a good LOC and hooked the eq up to that it would work? I know the eq isnt the best out there, but I'm "old school", been out of the competition thing for years. I loved this eq back in the day. I'm using all of the other same components in the car, and I know how good it sounded back then. I've had the amp in the car for awhile now, and miss the equalization control-and base control that I had with the EQ. Thanks

elduderino

You're asking me if you can get rid of hiss by adding an LOC onto an preamp level signal. I would expect it to get worse, not better.

In thinking about your problem a little, it occured to me to ask - is your F amp gain all the way down? Maybe your hiss is a product of level mismatching?

And BTW, old school is a Zapco PEQ on the seat. : )

CJams

That's not just old school, but ghetto as well

engine47

Actually, what I meant was to reconnect the factory amp and add an LOC to the "amplified" side, going to the speakers.

The sound I had wasn't really a hiss, but total distortion, and not really any volume. When I'd play with the wires, I could get a good sound for a half a second, then it would fade out again. I tried messing with the levels on the amp, no change. I also wired up an aftermarket stereo and connected the EQ/amplifier to it, and that sounded fine, so I know it has something to do with the factory stereo.

elduderino

And if messing with your wires changed it, I know that it's an install problem... sorry, man. Your OEM HU doesn't change when you mess about with the wires.

That will sound worse than properly using the preamp outputs. 100% guaranteed. Numerous members have tried it with more background hiss and worse sound than when they eventually used the preamp outs.

engine47

[QUOTE=elduderino]And if messing with your wires changed it, I know that it's an install problem... sorry, man. Your OEM HU doesn't change when you mess about with the wires.

Problem is, these wires are soldered, and it sounds totally fine when going directly to the amp without the EQ. When I say messing with the wires, I mean disconnecting and re-connecting the RCA's together. Oh well. Enough dead-horse beating!

elduderino

Oh, whoops, misunderstood, sorry.

Tsx536

That EQ definitely sounds like your problem. Can you get your hands on a different EQ to test with?