E46 HK Speakers Cutting Out - BMW Forum

crg · 01-25-2009, 12:51 PM

After listening to music for about 30 minutes the sound fades out of all speakers except for rear sub-woofers. After turning off for a few minutes and then back on, complete sound returns. It then fades out again after 5 minutes or so. Could this be amp or wiring problem?

BimmerE39 · 01-25-2009, 01:01 PM

It sounds to me like an amp problem although it could be a wiring problem as well. I'm leaning towards amp problem because at least in my experience, when an amp overheats it cuts back power to prevent a thermal overload. This sounds odd to me because the factory amplifiers should have ample cooling and aren't ultra powerful either. IDK on this one but to me it sounds like an amp problem.

crg · 01-25-2009, 01:09 PM

That seems probable considering the problem happens more frequently on warmer days. I'll assume the amp needs to be replaced...

BimmerE39 · 01-25-2009, 01:17 PM

You might have to, I've never had the problem with a factory amplifier, but it could also be a simple fix as well. I used to have a 4-channel amplifier in my E39 that would start cutting out on warm days within minutes of playing my music loud and a lot of what you are saying is happening is reminding me of those bad times. I'm hoping someone else will chime in on this. OE sound systems are not my forte.

drz · 01-25-2009, 01:25 PM

I work with a group that designs, manufactures, and sells car audio amplifier integrated circuits, and everything I read in this thread screams over-temperature shutdown.

da_bull · 01-25-2009, 10:37 PM

yuppers...

Also check your bass/loudness settings. If you listen to a lot of bass-heavy music, and also crank the bass and/or loudness settings on your radio, and then crank the volume up, the speakers arent really designed for that kind of abuse, and your forcing the amp to play notes its not really designed for, overheating it causing it to shut down until cool then its fine. Does this happen at low volumes too?

crg · 01-29-2009, 07:19 PM

I've never paid attention to the volume, although that sounds reasonable. Would you recommend replacing the amp? I've enjoyed the stereo for 2 years and it just started a couple of months ago. It seems to be happening more frequently as well.

da_bull · 01-29-2009, 07:54 PM

The amp is probably ok, I'd focus more on the speakers first.

crg · 01-30-2009, 06:25 PM

I'm continuing to have the problem, even after turning down the bass and listening to soft classical music. How should I determine if it's a speaker issue versus an amp issue? I have the HK "premium sound" (whether that makes any difference).

da_bull · 01-30-2009, 08:23 PM

The car is 9 years old and no telling how old the speakers are (E46 runs from 99-up, but I cant remember if they used the same ones prior), they're at least 9. I'd start there. The smaller ones usually go first, listen to each one closely and see if any crackle/hiss/pop/etc. at a medium volume.

crg · 02-01-2009, 12:29 PM

The front speakers seem to sound fine (when they're engaged). The total overall sound is fantastic...until all the sound fades back into just the sub woofers in back. Something is overheating... Is there any way of testing an amp before replacing it?

BimmerE39 · 02-01-2009, 03:28 PM

If I were you, and this is me just joking, but I would rip everything out and do a hardcore upgrade! In all seriousness, I don't know of any tests to check to see if it's not working properly. I've bench tested amplifiers before I installed them in my car but that was just to see that they would turn on and off. If it's an overheating problem I still think it would be an internal problem. You could always go to a good car audio shop and ask them to check it out for you. Chances are they are going to be more familiar with the system in your car than a BMW dealership would be. Just my $.02.