91 300D Radio Question
 

My 91 300D has the typical door and parcel shelf speakers along with a set in the front doors all driven by the factory Becker unit. This thing has never sounded good (since I own it) but recently the door speakers sound like they are torn / cracked.

Looking to do an overhaul (of just the speakers) I popped open the covers (front & rear) to find out that an unemployed butcher had already replaced the rear speakers. Thankfully he hadn't touched the fronts and I haven't opened the doors just yet.

Question #1: When I disconnect the amp (?) in the trunk the door speakers go quiet and the other 4 keep working. Is this the way the system should work?

Question #2: What size are the speakers in the doors?

Question #3: The foam in the rear speaker grills is deteriorated and falling out. Any suggestions for replacing this?

Thanks in advance for any help.

MB speakers have strong paper cone surrounds, making for long life but lowering the bass response a bit perhaps.
I would find some aftermarket speakers that fit or consider replacing them with OE speakers (cheap at a U-Pull-it)
As for the amp, it probably has that unusual habit of not driving one speaker if the other is disconnected, I can't say for sure what is going on but I would have bypassed the amplifier with an aftermarket amp with active crossovers feeding all speakers individually and NOT going through the fader on the console!
I also suggest you install bass blocking caps in the front speakers and door speakers when you get to replacing them, that will help the cones last a bit longer if you tend to crank the volume up.
DDH

Thanks for the tips. I've ordered these for the dash and these for the rear deck. As for the doors I need to pull one apart and see if these will fit (diameter and depth).

Looking at the wiring diagram in this thread eliminating the factory fader should be very easy. However with the factory radio that means there won't be any way to balance the system.

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