Servantguy

Hi folks,

Could I seek some expertise to verify my logic against please?

Logic 7 system on this 2012 E550, bass is lacking, and sub is not vibrating at all. Surround is off, and when I move the balance around Front to Rear, Left to Right, L front tweet is ok, but R front tweet does not output sound. Surround on/off, same. When I raise volume up, R front tweet comes to life and continues to output even as I reduce my volume. Then it stops outputting once I turn off the car and try again. Other door speakers, front and back, are fine.

Meanwhile, in all this, the rear deck does not appear to output any bass sound, only mid/high, regardless of sound level.

So - to isolate, I attached OEM replacement amps (main + subwoofer), both of them, and reset the audio system. Same behavior. No change.

Fuses 67 + 69 are fine (100% continuity when tested via Fluke MM).

A full set of OEM replacement speakers are on the way so I can test/replace speakers as needed for my next step, but while they travel, is there any other component I should test/replace in the chain while I wait, that could cause the behaviors above? C5 scan module is on the way, so unable to check for DTCs just yet.

My objective is to get the OEM system fully functional so I can hear and gauge for myself whether an aftermarket sub upgrade is needed.

p.s.
Subjectively, my reference of "good" is a 2006 E90 BMW with a Logic 7 system, and the stock setup with 2 underseat subwoofers are satisfactory for me. I really would just like to hear for myself how close the W212 OEM Logic 7 system can get to that.

Thank you folks! Just want to make sure I am not missing anything.

-sg-

konigstiger

"Attached"? Re-attached. "Reset"? Using MB diagnostics, and if so, were all fault codes cleared. Awaiting your reply, my "suggestion" replace amp (search part # 2129007108) any problems thereafter, if amp is purchased used clear all codes, transfer data from original to replacement amp, and confirm software is current using MB diagnostics.

Servantguy

Thank you! I'll let you know what the scan reveals. To clarify "attached", I meant I replaced parts 212 900 71 08 and 211 870 51 89 with used ones, and unplugged fuses 67 and 69 to "reset" the audio system.

Servantguy

Closing the loop here: it turned out to be a bad sub:


nasty



dead


replacement

Good as new.

drdantheman1

I have the same problem with my LF speakers. No sound at times unless I raise the volume. Was your issue solved with replacing those speakers as well? I'm already on my third amp but my issue keeps occurring sporadically, haven't replaced the speakers or wiring yet.

DFWdude

It's disappointing to see where this subwoofer failed. Given the decades upon decades of speaker development, one might think that these weak areas were perfected long ago. Bad design, me thinks.

Servantguy

Hi - this is the intermittent bit. Right now the original RF tweeter is behaving properly after visually inspecting it and reseating its triangular mount upon the door. I hope it continues, but I did get a full replacement L7 speaker set so am able to replace the rest as they/if they go. It made sense $ wise when I was shopping for a sub - the speaker set was not much more.

One note: I reverted back to the old amps - both of them.

Servantguy

I have thoughts along those lines as well - I was expecting some dramatic evidence of user error or physical trauma on the sub (e.g. puncture marks, cuts or rips, etc) but no.

Then again, I'm sure on some level some compromise needed to be made between durability vs the ability to fit that custom sub in there and make use of "cutting edge materials" when these came out in 2012.

But - so glad I actually hear low end now! I don't need much, but there is a significant difference with vs without the sub.

Next up: getting that 10.25 in screen plus head unit upgrade in. Gotta keep busy!