EPS Subwoofer does not turn on

[Z K]

Has anyone had a problem with their enhanced premium sound where the underseat subwoofers do not turn on sometimes? When I start the car, there is a random chance that the subwoofer will work. Sometimes it does, sometimes it does not. If I park the car for 30 minutes and come back, I can restart the car and sometimes the subwoofer will be working again or sometimes not.

I had the dealer look at it and they could not reproduce the problem. They mentioned it might be due to low battery as it will sometimes turn off accessories if it is low... I never get any low battery warning or anything and they say the battery level looks fine.

[Z K]

Anyone know anything about this? Still happens and seems to be random.

[toddcc1]

Originally Posted by Z K

Anyone know anything about this? Still happens and seems to be random.

I'm not a mechanic, but "low battery" sounds like bs. Are one of your other speakers blown?

I don't know if the enhanced premium sound subs are powered via independent amplifiers, I don't believe they are; but if you have a blown speaker somewhere else, it will alter the impedance of the amplifier. Often times, the result is the amplifier heating up, cutting out, then cutting back on.

[toddcc1]

Originally Posted by toddcc1

I'm not a mechanic, but "low battery" sounds like bs. Are one of your other speakers blown?

I don't know if the enhanced premium sound subs are powered via independent amplifiers, I don't believe they are; but if you have a blown speaker somewhere else, it will alter the impedance of the amplifier. Often times, the result is the amplifier heating up, cutting out, then cutting back on.

Don't know if you saw/read this...

http://www.m3post.com/forums/showthr...highlight=bass

[djseto]

Anything come out of this? Same thing started happening to me (I replied to a different thread). Just found this one using the Search button...

[Z K]

Originally Posted by toddcc1

I'm not a mechanic, but "low battery" sounds like bs. Are one of your other speakers blown?

I don't know if the enhanced premium sound subs are powered via independent amplifiers, I don't believe they are; but if you have a blown speaker somewhere else, it will alter the impedance of the amplifier. Often times, the result is the amplifier heating up, cutting out, then cutting back on.

This amplifier heating up thing sounds interesting... but the subwoofer will not come on sometimes when coming from a completely cold start. The amplifier should be cold at this point.

[djseto]

Mine happened like 2 min after I got into my car from the gym so I also agree that overheating probably wasn't an issue in my case.

What did your dealer end up doing? You started this thread last year.

[Z K]

Originally Posted by djseto

Mine happened like 2 min after I got into my car from the gym so I also agree that overheating probably wasn't an issue in my case.

What did your dealer end up doing? You started this thread last year.

Dealer couldn't reproduce the problem so they couldn't do anything. I brought it in twice and twice they couldn't do anything.

They mentioned my KW EDC modules in the trunk might be causing electrical interference. Seemed like BS as I don't see how a self contained module attached to the suspension can affect the audio system.

[djseto]

does it still happen?

[Z K]

Originally Posted by djseto

does it still happen?

It happens on occasion but I would say 80% of the time it is fine. Every now and then I can hear lack of bass from the subwoofers. I should mention on the KW EDC modules, I had the subwoofer issue way before I had those installed.

[IrishCoffee]

Originally Posted by Z K

It happens on occasion but I would say 80% of the time it is fine. Every now and then I can hear lack of bass from the subwoofers. I should mention on the KW EDC modules, I had the subwoofer issue way before I had those installed.

Try this... next time you turn your car on and the bass seems to be working, move your balance from right to left. If there is bass on only one side then it could be a loose lead on the speaker that is working, while the other is completely broken.

I could see that if the speakers were defective like mine were that one of them could come in and out. I didn't notice that one of mine was busted until both of them went out. Bass is not very directional so it's hard to tell if both are working.

If you can isolate the problem to one speaker that is intermittent, then pull the other one out from under the seat and look at it and see if you have the same issue as me (in the thread link posted above).

Now, if you pan left to right and both underseat woofers are working then it is very unlikely that it is the speakers. I can't imagine both failing and both coming back intermittently. The problem at that point is more than likely hardware (amp) related.

The KW EDC module excuse is complete BS. Interference? Is that a joke? That would cause more sound/noise than less.

[THE TECH]

If the speakers themselves have never been touched, my first guess is that it's the amp. Speakers either work or don't.

[IrishCoffee]

Originally Posted by THE TECH

If the speakers themselves have never been touched, my first guess is that it's the amp. Speakers either work or don't.

I would tend to agree with this, but it seems in most cases I've read on here (including my own) the problems are with the woofers themselves. That's why I suggested the quick troubleshooting above. If it's intermittent and both woofers are working (when there is bass) then I'd say it's the amp.

I have seen cases of speakers that have loose leads connecting to the voice coil work intermittently, but it is very very rare.

[Z K]

Originally Posted by IrishCoffee

I would tend to agree with this, but it seems in most cases I've read on here (including my own) the problems are with the woofers themselves. That's why I suggested the quick troubleshooting above. If it's intermittent and both woofers are working (when there is bass) then I'd say it's the amp.

I have seen cases of speakers that have loose leads connecting to the voice coil work intermittently, but it is very very rare.

Well, in my case, the subwoofer is either on or off when driving, it never switches on and off while operating the car. You'd figure with loose ends it would intermittently switch on and off while driving. With me, it either has bass when I start the car or there's no bass and that doesn't change during the drive.

[IrishCoffee]

Originally Posted by Z K

Well, in my case, the subwoofer is either on or off when driving, it never switches on and off while operating the car. You'd figure with loose ends it would intermittently switch on and off while driving. With me, it either has bass when I start the car or there's no bass and that doesn't change during the drive.

Ah, OK then it's definitely not the speakers. I misunderstood the problem.

I would imagine it would be the amp or the processor inside the amp unit then. Not sure what else it could really be.

[Z K]

Originally Posted by IrishCoffee

Ah, OK then it's definitely not the speakers. I misunderstood the problem.

I would imagine it would be the amp or the processor inside the amp unit then. Not sure what else it could really be.

Well, it does look like that. The signal going to the amp is always the same right? So it is something inside the amp that splits the signal and sends it out the audio channels including the subwoofer. And I did notice that the subwoofer will come and go occasionally while driving. A faulty amp?

I don't mind buying a new amp to fix the issue if that is the problem but that's an expensive mistake if I buy it and that isn't the problem... Any way to make sure it is the amp?

[Krockit1]

I had this issue with my 2010. In fact no bass in the right bank at all. I complained to the dealer, they set an appointment and found enough sound coming through all the right side speaks that they declared it was operating. Days later, on an extended drive, the right side crackled, boomed and came to life. EPS wasn't bad after all! When I fired the car up to head home 3 days later... bass was gone again and never came back. Relayed this to the dealer and long story short, after one more appointment they ended up installing a new amp. ($1800 if you had to buy it outright, damn!). And the stereo has been worth listening to ever since. Not world class, not worth the $1900 option price, but very good.

[Z K]

Originally Posted by Krockit1

I had this issue with my 2010. In fact no bass in the right bank at all. I complained to the dealer, they set an appointment and found enough sound coming through all the right side speaks that they declared it was operating. Days later, on an extended drive, the right side crackled, boomed and came to life. EPS wasn't bad after all! When I fired the car up to head home 3 days later... bass was gone again and never came back. Relayed this to the dealer and long story short, after one more appointment they ended up installing a new amp. ($1800 if you had to buy it outright, damn!). And the stereo has been worth listening to ever since. Not world class, not worth the $1900 option price, but very good.

Wow, did it actually crackle and boom back? I never really notice the transition from subwoofer working to no subwoofer. I just notice it when the audio sounds strange and I realize there's no bass. Otherwise I notice it when I start the car, I pay attention to see if the subs are on or not.

There are 2 subs under the seats, right? From my experience, both work or don't work. I've never had bass from one side and not the other.

The dealer was no help. They kept saying it can be a battery issue and every time I'm there, the sub is working.

[Krockit1]

Yep, it was freaky but that's what happened. There is a sub under each seat, correct. And it's tight down there, so much so that you can't mount a sub with enough room to travel the speaker cone to develop really good, big and full bass. The right bank was never right in this car. And Yeah- I was insistent with my dealer. I actually think if my service manager wasn't a musician himself, I wouldn't have gotten the same break.

[Z K]

Just to update this thread. The dealer could not diagnose the problem because it was intermittent. Every time I went, they could not reproduce the problem.

I tried replacing the subwoofers with upgraded ghost subs... which did not solve my problem. My stock subwoofers looked fine. No broken speaker cables like some people have seen.

What I ended up doing was replacing the amplifier and that solved the problem. Somehow all channels worked except the subwoofer channels. Also, there's many different models of EPS (Individual Audio) amplifiers so I went through a few used amps before I found one that worked without re-wiring or coding. The newer EPS amps would work, but you need to re-pin the plugs and add new connectors to make it work. I ordered a new amp from the dealer but they were not able to give me the wiring diagram and a step by step on how to re-wire the harness and code the amp. They could do it for me and it was not cheap.

Since the amps are out of production, I had to rely on eBay and I'd pick up an amp when one showed up every few years. Real OEM helped as it had a list of which parts were directly compatible.

Anyway, happy my subwoofers finally work after 8 years of it not working.

Going on 12 years of happy ownership and still enjoying the M3!