I have been going crazy trying to fix this problem.

Here is my setup.

2004 non nav TSX - stock HU.
Alipne MRV-F450 powering PG components up front, and Alpine 6x9s in the rear. Back doors not connected.
Wired up as per DIY using female RCA plugs.

There is a little noise with the car on or off, but not bad. I can remove it by playing with the gain. With the HU off there is no noise. The problem I have is a snapping sound that is tied to the engine fan turning off. Here is what I know:

HU off - no noise.
HU on, engine off - slight noise, no snapping.
HU on, engine on - slight noise, snap sound when engine fan kicks off.

The snap sound is independant of HU volume setting or amp gain setting. If I turn the volume high enough I can no longer hear the snapping. I have tried mute plugs into the RCAs which run down the passenger side of the car to the amp in the trunk. With mute plugs in the RCAs the noise is gone and the snapping stops. I have tried grounding the HU to the post for the stock amp, which made no difference.


At this point I can think of one thing I haven't tried - running a ground from the back of the HU. I have rewired the signal RCA's and am farily certain they are sound.


If anyone has an idea please let me know.

 

I went though the same problem. Not too many people on the forum have the problem or something because I got no response when I posted seeking remedy for the snaps awhile back. I've tried everything and only two remedies seem to help: lower the gain on the amp that power your fronts, and ground your amp really well.

I have the JL Slash 300/4 and 300/2. I set the gain of the 300/4 at around 10 or 11 o'clock position for the fronts and at 8 o'clock (or a notch above zero gain) for the rears. The 300/2 is for the sub and that does not induce any snap regardless of gain position.

On grounding the amps, I use the widest wire terminators I could find for maximum area of contact with the chasiss. I found some at Home Depot for 4 gauge wires with 1/2" bolt holes. I grounded my amps at the seatbelt bolts bellow the rear seat after I sanded all the paint around the bolt holes, around half inch width all around.

I also upgraded the ground wire to the battery since the grounding takes place at the negative terminal of the battery. No point get good grounding to the chasiss then have a "sucky" connection to the battery ground. I got a 2 gauge battery wire from the Pep Boys and replaced the stock ground wire. It should run you around $10. Again I sanded the area around the bolt hole on the chassis before I attached the new ground terminator. I'm getting some slight surface rust in the area after a few weeks though, so I have to attach some of those battery terminal "felt washers".

Anyways the result has been quite dramatic. The snaps still comes once in a long while but ten times less often and less loud: almost like a static click than a rock on the windshield snap.

I'm still working to eliminate it 100%. Nest things I'll try would be power line filters on the fans, isolate power to the HU and see what happens. When I succeed, I'll post the findings.

 

Thanks for the input. Re-wiring the amp and battery grounds are about the only things I haven't tried yet. Currently I have 8 guage grounding the amp to a drilled hole in the pass through area behind the rear seats. Hopefully I get time this weekend to run a new ground.

I will let you know how it works.

 

It sounds as if there is a transient coming from the HU. It is probably coming inthe power or ground wires when this occurs.

It's not easy, but I'd try:

1) grabbing the HU harness, cutting the ground loose, and running a long test wire and grounding it with the amp.

2) Putting an in-line filter on the ACC line for the HU. This actually has a slightly higher spercentage shot, but is harder and costs more.

 

elduderino, check your PM please.

 

Hi Eld,

Thanks for all your help in the past. Now where can I find this HU harness?

Thank you.

 

I tried moving my amp ground and double checking the battery ground. Both are now well grounded and the noise is still there.

I will try to find an in line filter and pop it in shortly.

Thanks for the ideas. I'll follow up when I get time to test them.

 

Sorry Eld.,

I pressed "Submit Reply" before finishing the research. Is the HU harness the one that is connected to the back of the CD Player, since that's a part of the Audio Unit, correct?

If it is, then A2 must be the power line to install the in-line filter, and A20 is the ground, according to this link under e_lectro listing of connectors https://acurazine.com/forums/showthr...ghlight=sticky

I was thinking of using the S-15-A DSF from crutchfield seen here http://www.crutchfield.com/S-OLyrVGN...search=filters . Do you see any problem with using this?

Thanks again.

 

I think I am going crazy. Tried a few more things and the noise is still there. Here is what I have done lately.

1) In line filter on white/blue line into HU - noise still there.
2) In line filter on yellow/red line into HU - noise still there.
3) MP3 player w/ batteries into RCAs which go into amp - no noise. This also eliminates induced noise on RCA cables along passenger side.
4) HU ground cut and grounded to amp ground - noise still there.
5) In line filter on turn on wire into amp - noise still there.

After trying #5 I realized I was grasping so I called it a night . Any ideas on what else I can try. The only thing I can think of is to get higher quality female RCAs to use for connecting to the HU outputs. I have resoldered the RCAs at least twice, and am running out of ideas. I could always run an aftermarket HU, but I don't want to resort to this.

 

I don't have the manual in front of me, but I did just cut these wires this past weekend - I thought the white/blue only went to the factory amp. If I'm mistaken please ignore.

You've seen this thread starting about a quarter of the way down?
https://acurazine.com/forums/showthr...9&page=4&pp=25
Have you tried connecting a GLI to see if it eliminates the problem? You have a F450, I have an F340 - has to be the same internals. I had noise from the get go and the occasionally snap. A lot of it was due to a bad ground, I sanded the shit out of the grounding point and it helped, but only a GLI eliminated it. And I had tried a bunch of stuff - borrowed speakers to see if it was the speakers, hooked-up another alpine amp I had, resoldered the RCA connectors on the factory HU, took RCA cables from home and moved them all around the car to see if it was being inducted thru the cables. Nothing did shit except a better ground and a GLI. I was beginning to think the HU was defective when I came across the above thread. I mention that our amps likely have the same internals as I suspect that maybe, maybe these amps do not "like" a balance input. I'm currently running the factory HU output to an alpine HU AUX in, same wiring (RCA and speaker wires), amps, speakers, no GLI and no noise or snaps. And the new HU battery connection was the stock amp's lead, so I don't suspect the power leads are "dirty", not using the factory ground lead, but I think it's grounded to the stock grounding point. Point being that everything downstream of the factory HU does not have noise issues when connected to a different HU and the factory HU does not have noise issues when not connected directly to that amp. So, short story long, have you tried a GLI?

 

Yes, I am currently using GLIs in my setup. On top of the snapping issue I also have some high frequency noise, which the GLIs help reduce.

I agree that from the RCAs to the AMP is clean, and the HU power and ground inputs now appear to be clean. This poses the question of 'where the %$@! is the noise coming from?'. Since the HU was clean sounding before I added the amp I doubt that it is the problem. Trying the MP3 player eliminated the RCA path as causing the problem as well. You said you moved the amp ground, where is it currently located? I assume under the rear seat, but please confirm.


I noticed one other funny thing yesterday. If the car is running but the HVAC is off I don't get the snapping noise. This is likely due to the engine fan not being turned on and off as much. If I turn off the car and turn on the HVAC I also don't get any snapping. It only seems to occur with the HU on, the car running, and the HVAC on.

I will try regrounding the amp, but I don't expect a change. Thanks for the suggestions.

 

Wow, at first I thought I was incredibly lucky when I saw this thread. Haven't been on here for a few months, but I thought I'd check in to see if I could rectify my intermitent popping noises... lo and behold, this thread was on the top! Unfortunately, you guys seem to be similarly perplexed.

My situation: I installed a 4-channel amp, CDT fronts, sub, and line driver last year. After a few (thousand) initial problems, the system sounded great. A short time ago, though, the pops that you guys have been describing have sprung up. As close as I can tell, they're tied to the engine fan on/off transitions, though it is hardly consistent or obvious.

The curious thing is that it took months for this problem to appear. I'll start by checking if the amp ground has come loose. If that doesn't appear to be the problem, I'm confused as hell. I haven't made any changes to the system. Any luck Tiguron and/or Solaris?

 

My problem was not always present either. I figure it started about 2 months ago. The only thing I changed at that time was the wiring from the amp to the rear 6x9s. I also added some sound deadening to the trunk. There is no way that this should have caused the problem.

The problem may be tied to the engine and its electrical system. There is a chance that grounding the engine block better may fix it, but I doubt it. Unfortunatley I am out of town for the next week so I won't be able to try anything until I get back.

There are enough of us with this issue that someone should trip over the answer soon enough .

 

I've actually been using that same grounding point, I just sanded all the paint off the spot for a better connection. If you lift the spare tire cover all the way up to reveal the fuel pump (?) access panel, there is a factory ground point near the panel. But if you've tried different points, I wouldn't have high hopes for moving the ground to solve the problem.

Any chance you didn't experience the snap before adding a GLI? The reason I ask being that possibly the GLI could be picking up interference from the relay(s) kicking on/off or wires leading to/from. Have you tried moving the GLI?

 

The noise is there with or without the GLI.

 

I thought an in line filter would for sure work.

Did you put the in line filter on the HU ACC line or the constant power line? One on each might help. $16 at radio shack.

Are you still using the OEM amp for anything?

 

Crossover location?

 

No crossover. Simple set up - HU to spliced female RCAs, into GLI, into amp. Components up front, 6x9s in the rear, back doors not connected.

I tried the in line filter on the ACC and the constant power. I only have one so I didn't do both at the same time. There is a chance I used the wrong input wires though. I tried the white/blue and yellow/red which go into the lower (blue) harness on the HU. There may be a different input power source to use, I'm not sure.

 

I should have been more specific, I meant the location of the speaker crossovers - you stated you have component speakers, no?

 

oh - those crossovers.

Driver's side is located above the hood release latch, on the support that holds the plastic molding in place. In between the steering wheel and the side wall. The power wire is routed so it doesn't come close to it and crosses the line at 90 degrees.

The passenger side is wedged behind the fan/glovebox. I thought it might be picking up noise, but wouldn't the portable MP3 player test eliminate the speakers as a problem?

 

Right, yeah, good point - assuming of course that the engine was running and fan clicking on/off with the player connected...

I'm out of guesses. You can connect both constant power and switched power to the inline filter as the same time and test that with the one filter you have. The switched power lead I believe is only to prevent from turning on the radio without the key, so you wouldn't inadvertantly drain the battery.

 

I'll be away from my car and computer for a few days so don't look for anything from me until next week.

With any luck one of you will solve the problem before I get back .

 

How long is your amp ground wire I called alpine about this same problem & they said shorten my groung wire mine was like 3 feet.

 

any luck, fellas?

 

Just got back into town. I haven't tried anything yet. In a day or two I hope to try the inline filter with both the power and the remote lines. Other than that I am running out of ideas.

If the filter doesn't work I may look at a different amp and see if the problem is still there. It simply may be that the Alpine amp can't filter the spike out very well. I will probably try a PG or JL amp, but haven't researched anything yet.

 

In terms of trying different amps. I have personally tried the JL amps and the snap is still there: loud snap at gain above 50%, and static snap at 25% gain.

 

Try the filter first! Most auto parts stores even have them by the stereo stuff.

I also have an Alpine MRV-F450 running the fronts, rear doors and the Alpine E 12. Then I have an Alpine MRP-240 running the 6x9's and 1 Alpine E 10".

Alpines input filters are pretty weak! I get a snap when switching my Aux3 back to the neutral position.

 

Well I finally found a few hours to tinker with my system again.

I tried the inline filter on both the constant and switched power and it made no real difference. There may have been a minor change in the mximum noise of the snap, but it is definitely still there and still too loud.

The next things I tried were with the power lines for the HVAC part of the HU. Longshot, but I figured I would try. The only thing I noticed was one of the switched power lines looked like it was seriously crimped at the factory, almost to the point of being severed. No big deal I just patched it up.

Nothing seemed to fix the problem. At the end of it all I realized that the sound quality with the GLIs installed was almost the same as without them. Since I am not a fan of using GLIs I decided to run without them for a few days. Now the snap is gone. Well - not 100% gone, but almost. Instead of a loud crack evertime the fan kicks off, I get a barely audible crackle about once every 10-15 minutes. I can live with that.

Overall noise quality is not quite where I want it. I think I am going to drop in a line driver so I can let the Apline amp do its thing.

I am still in the dark as to the actual cause of the problem in the first place. When I ran an MP3 player through the RCA's and the GLI there was no snap. The GLIs must not be causing the noise, but they sure don't remove it.

I should have the line driver in shortly and I will follow up with final (hopefully) feedback on my system.

 

Curious, does the snap vary with volume?

 

FYI, I've tried the line-driver from PG and that didn't help. The volume of the snap seem to relate directly to how much you applify the original signal. It doesn't matter if you amplify it with the line-driver or the gain from the amp. Just to let you know. May be a line driver from another manufacturer will help. Thanks for keep on fighting, because I pretty much gave up.

 

Well, if the volume of the snap is music volume dependent, that could explain the MP3 player test result. No snap as the output voltage is lower from the portable player than the HU - couple hundered millivolts max as opposed to 2.5V max. Just a thought.

 

What model, do you know? I had(have) a PG 2way Xover/line driver [which I'm looking to sell BTW] and I found that keeping the HU below 30 resulted in a better sounding signal with diminished 'artefacts'. Currently I'm piping the HU output to aftermarket HU input and the volume set at 27. No problems, no noise, no strange shit - oh, also direct driving my tweeters, so no crossovers to pickup any noise either (and no GLI).

 

I got the newest PG SLD44. With it, the sound quality improved dramatically. My front CDT components really sang at about 45% gain. But when it snaps, man it was loud and painful to my ears, so I took it out.

I like your idea of channeling the out put of the OEM HU to an after market HU. I haven't tried that yet.

 

Since piping the OEM HU signals to an aftermarket HU seems to eliminate the noise gremlins for Spoon, this brings up an interesting question: Would a JL Cleansweep be effective in cleaning up the signals fed to it. I know the OEM signals are flat so we won't benefit from the Cleansweep's D2A and D2A signal equilization, but would we benefit from any filtering effect that the Cleansweep may have on the OEM signals.

Anyone tried it yet?

 

Well, I wouldn't go so far as to say that. I don't have any appreciable noise (I don't hear any) nor a snapping sound, but I wouldn't attribute it to the HU daisy chain, so to speak. I'm also triamping, allowing me to lower the gains (and factory HU volume) and essentially using the aftermarket as a preamp/signal processor (I bought it for the crossover and time correction, mp3 play too). The noise I experienced in the past had to do with a poor ground and, I believe, sending the balanced outputs of the HU to my non-balanced input accepting amp. I wouldn't recommend my setup as a noise issue solution, hell maybe I'm just lucky with this configuration. I'd really like to know the source of this snapping because if I change things in the future (I plan to) this might become a problem. The problem I have with the idea of filtering the signal is what exactly would be filtered? If it is a HU problem, how could you separate it from the audio signal? Is it a voltage spike essentially clipping the signal at that instance, how could you remove it? Hopefully it is some sort of inducted noise and maybe routing the wires differently will make a difference. Tiguron sees a correlation between the snap and the fan, and no change filtering the power inputs to the HU, so maybe it's inducted. But I have no idea, though I am extremely curious as to the cause.

 

My snapping noise is independant of the HU volume and the gain on the amp. At least I think so. I will retest with different gain settings and get back to you. If the volume is at normal listening level most of the snaps are drowned out by the music. At lower volume settings the snaps are much more noticeable. Remember this was with the GLIs in place and has since diminished alot.

The reason I want to try a line driver is to hopefully let me have a clean and loud sound in the car again. Currently I have the gains set so low that even with the HU at 35 the sound is too low. At low HU settings I can still hear some noise.

One thing I noticed with the snap noise was that if the RCA is attached to the + signal and the shield is grounded INSTEAD of being connected to the -, the snap in gone. Of course the sound quality and amplitude is horrible, but from what I can tell the snap is carried in the negative signal of the HU output. Adjusting the ground, or tying the RCA shield to ground makes no difference, the snap remains. I could be wrong about the source of the snap. I think the - signal carries the spike while the + doesn't. My guess is the factory amp and certain aftermarket amps are better at filtering it out that others.

Let me know if my logic makes any sense, or am I completely off on my guess.

 

The guy that realized that output signal is balanced also noted that grounding either output makes it sound like shit. I too tried using the HU + signal to RCA center pin and chassis ground to shield and as you noted it sounds bad, at least with the car running there was alternator noise, car off it was fine. However, the way to know if the - signal that is corrupted somehow, would be to connect that to the center pin and see if you still get a snap. Since the outputs are just 180 degrees out of phase with respect to each other, I'm willing to bet you'll not notice a difference. Obviously I don't know, but I'm willing to suspect that the snap is related to sending a balanced output to your amp. Since you get a snap with + to pin and - to shield, but no snap with - not connected to shield (and therefore have a single ended output), the snap seems to be related to the balanced output. So, back to the GLI - that will eliminate the gounding of either output (+, -) and isolate the amp from the balanced signal. Have you tried connecting the GLI right before you amp, physically - not near the center console or anywhere it could pick-up noise?

 

Actually the most recent location of my GLI was in the trunk, right before the amp. I have also had it behind the dash where the factory amp was located. Both produced the snap sound. I may try a different location, but I don't expect it to change anything.

My next move is to order a SLD44 line driver. I will try it both with RCA inputs and then as a LOC if needed. Even if it doesn't help the snap noise I figure it will help with overall sound quality and volume level.

 

Bump ... anyone made any progress on this?

 

I have ordered a PG SLD44 and should have it in a week or so. Once I get it I will tinker with a GLI and the line driver to see if any combination gives me good sound without the snap.

As soon as I have any results I will post.