[Mr-Biggles]

Hi all,

I apologize if this has already been dealt with but I can’t find anything.

I recently replaced the battery in my 2009 328. During the change there was a loud humming noise. After the changed battery the subwoofers made this terrible crackling noise. I tried changing the battery back and no change - still crackling. Thinking it might be an issue with the amp I ordered a new one with no change. Then today I noticed that if I balance it to the right suddenly the subwoofers start to work and the cracklings disapears and it sounds great - from the right channel only. This is regardless of source (radio,aux)

Please help! I’ve already spent $60 on an amp that apparently wasn’t the issue and I’d rather not spend $300 on a new headunit - especially if that’s not even the issue.

[Mr-Biggles]

So i decided to play with the subs directly - seeing as they were making the noise. I started with the passenger and disconnected it. So no more crackle. No bass but no crackle. No driver side bass either. So thinking that the passenger side worked great when faded right I thought maybe it’s the driver side? So I pulled the plug on the driver side. I also noted that there were fewer wires - I think maybe they are wired in sequence passenger to driver? Maybe be that’s why when I pulled the passenger line no bass at all? Anyway pulled the driver left the passenger plugged in and... SUCCESS! BASS (obviously nit on the drivers side) and no static or crackle!

Anyone have any thoughts why? I’m pretty happy as now it doesn’t sound half bad. Anyone think a new subwoofer would do the trick? I’m stumped as to why they would both crap out if one is bad but???

[ctuna]

Since you only spent 60 bucks on an OEM amp an you have an 09
I would assume you have the Hi Fi system. For anybody to make
some comments we would have to know which system you have .

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.bmwmotorsports.org/pdf/e7...%20Systems.pdf
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/showthread.php?t=641323
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...4&d=1278871872

The weakest link in the Hi Fi system is the amp but the speakers aren't that far behind it.

You could swap them left to right to isolate the problem or do a resistance check at the amp connector as a first pass test.

You didn't say what you plugged that speaker into either the stock amp is weak with the under seats to start with.
Could be the Head unit as well.

[Mr-Biggles]

Thanks ctuna right on the money it’s the hifi system.

I just completely unplugged the driver side and left it dangling.

Could you elaborate on a resistance check? I did think about swapping the subs but it’s a PIA to even get to them

[ctuna]

Not as bad as you might think once you have done it.
The speakers should measure about 2 ohms.
The seat is held down my 4 T50 Torx bolts and can be tilted
back. There are a lot of grill fastners. The speaker pod is held
in by two nuts.
Since you said you disconnected one of the speakers you must
have gotten most of the way there.
To get the carpet loose you must pull up the door seal.

http://www.e90post.com/forums/attach...3&d=1329017429