[ghost_1on]

Hi all,

So I've been battling this issue for about 3 months now but only recently had the courage to actually start replacing parts since my BMW 535i 2011 is now out of warranty.

About 3 months ago all the bass in my car cut out but the speakers remained functional. I checked with the balance/fader and all the speakers(front and back) were outputting sound.

This had happened before but usually within 15 to 30 minutes the bass would return but this time it was out for several days. One day it came back and stayed functional for about a week.

So I read through the forums and found that the issue was most likely my amplifier. I ordered a donor amplifier of the same model off ebay and 2 days before it arrived the bass returned in my car.

I went ahead and changed the amplifier successfully and the bass remained functional for about 2 weeks until yesterday - while playing my music fairly loudly it cut out again and has not yet returned. So maybe the amplifier wasn't the issue? Is there a chance this donor amplifier also gave out or had issues?

Another important point is I noticed while testing my sound prior to the install of the new amp - that my driver said subwoofer was not working at all. The bass was only coming from the passenger side. I read in the forums this could possibly cause a short to the amplifier and also could be a reason the bass is cutting out - but woud all the bass cut out even on the working subwoofer?

Really would like to fix this issue myself as this car has already been through quite a bit in terms of repairs which were luckily covered by a third party warranty.

All and any help is appreciated!

[ghost_1on]

Any feedback would be appreciated - currently stuck

[lsturbointeg]

i'm stumped as i thought i would be your amplifier. the fact that it's doing it again tho is weird. maybe a short somewhere on one your speakers grounding out the system? i don't know. i would say if you have the budget upgrade your system with a complete overhaul of your speakers and the factory amp

[TZ]

Base on your description, I would suggest to check all the harnesses and connector for loosing pin.

[ghost_1on]

Thanks for the replies guys.

@TZ nice to see you again!

You think it might be one of my speakers causing a short? Could one loose connection or broken speaker cause all the bass or the amp to not function correctly?

I know my driverside underseat sub is not working and I believe one of my other speakers is blown (scratchy rubbing sound when playing loud music).

Any chance the donor amp is broken also or should I stop buying amps lol

[Hoa]

If you swapped the amp and still have same issue, I'm leaning towards the head unit or loose connection between amp and head unit. A bad midrange or tweeter will not short out the bass on your subwoofer especially if it still output audio and nothing is coming from the subwoofer.

A bad subwoofer could be the problem but it's rare that it would be intermittent. A bad voice coil is like a bad incandescent light bulb, it just won't work anymore because it's blown. Unplug the subwoofer that you know is bad just to rule out that it is not shorting out your amp. I doubt it is the issue though. You can reset the amp by unplugging it for 1 minute and plug it back in. If it still have the same issue, I suspect it is your head unit or connection between the head unit and your amp.

[TZ]

Originally Posted by ghost_1on

Thanks for the replies guys.

@TZ nice to see you again!

You think it might be one of my speakers causing a short? Could one loose connection or broken speaker cause all the bass or the amp to not function correctly?

I know my driverside underseat sub is not working and I believe one of my other speakers is blown (scratchy rubbing sound when playing loud music).

Any chance the donor amp is broken also or should I stop buying amps lol

Agreed with Hoa. If you swapped the AMP and have the same issue. Most likely is not the AMP problem.

Attached is the audio diagram for H-Fi system that I believe your car has it. The HU passes multi channel analog signals to AMP. Since the HU works for the front, door and back speakers. It is less likely the HU is bad. So I would suspect the connection between HU and AMP first.

A speaker can be simply checked with a multimeter.

[ghost_1on]

Hi all,

Thanks for the feedback so here is what I'm going to try:
1. Disconnecting the bad subwoofer and seeing if that helps
2. Disconnecting the amp for 1 minute and seeing if that helps

Assuming this does not fix the issue and the connection is indeed bad between the HU and AMP - what is my course of action? validating the wire all along the car from the headunit to the amp? I'm still pretty new at this - would it be better to bring to an audio shop to check that out?

Any idea what the cost might be to get that checked/fixed? My assumption with this car is nothing under 1000.00 :@

[TZ]

Before seeing a professional, I would get to the HU, unplug the connectors to exam any blend or extracted pin, loose wire cramp... Then plug the connectors back and try it.

[ghost_1on]

Thank You TZ - I will give this a try.

[ghost_1on]

Just wanted to post back - the issue wasn't the amplifier or headunit, it seems that my other subwoofer under the passenger seat blew as well. Must of been cutting in and out and finally gave up.

I replaced both with donor parts from Ebay for a fraction of the cost and all is working well now.

So if anyone faces a similar issue I would first start with your amp which is an easy fix/change and then check both subwoofers (they provide the majority of the quality of sound!)

Thanks everyone