Fix for speaker issues

[Bao1303]

So, not going into Burmester vs Bose discussion, but chose burmester based on demo car listening. however, not been happy with it. Too much rattles and resonances at elevated volumes, which I thought was due to insufficient s stiffening /deadening of the panels. However after some investigation and frequency sweeps using it the fader to locate issues it was clear that the right side was way worse than the left. Took it in, and they swapped the front and back right midrange units. Didnt help. Long story short(ish); they had another go - didn't help. Got tired and removed rear right doorpanel myself (super easy - kudos to porshe) and found that there is a plate in front of the speaker! This is some kind of production thing, that plate has to be snapped off. But even then there a are remains from the moldings and wrong tolerances which leads to the actual membrane support touching the panel when extended. Added a few washers under the driver as a quick fix which resolved the issue.

This is a combination of design and production flaw, and I will dismantle the other doors as well and have a look. Not sure about the Bose, but if the midrange unit is using the same fixation as the Burm. It may have the same issues. When dismantled, it is very easy to check if there is any interference with a calliper

If anyones interested Ill post pics. When doing the other doors

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[f1eng]

If anyones interested Ill post pics. When doing the other doors

I'm interested!
I have a 60 year long interest in speaker driver design and one of my best friends designs drivers for several manufacturers.
Always interested in what people are using.

 

[Bao1303]

Its not the speaker itself but the internal FRP door insert acting as support and"front baffle" that is the problem. Suspect they must have changed supplier during covid or something, and not checked tolerancees as it is really a silly error

 

[Bao1303]

Top pic shows how its supposed to be, bottom how it was... Thick plate in front of speaker. When smapping it off, there are still small remains of plastic from the "cross" remaining, interfering with the woofer suspension, distorting the sound. Put washers under the woofer to increase distance which fixed it. But then it might not seal perfectly against the "baffle". Should get a gasket instead. However not sure how much it matters with slight bleeding between baffle and driver as this isnt really a closed cabinet anyhow

 

[Bao1303]

Gasket and/or washers may not be necessary if the remaining plastic notchses ar grinded down flush will try that first

 

[ciaranob]

I get why you are doing this yourself, I'd be very much like-minded, however given the cost of this system, would you not make the dealership fix the blatant production/delivery mistake - once you go DIY they will have their out re warranty repairs!

That said, I totally empathize not having to deal with techs at the dealership though and who knows who (in respect experience) you'd get assigned to remedy the mistake.

Go slow with the grinder !!

 

[Bao1303]

I get why you are doing this yourself, I'd be very much like-minded, however given the cost of this system, would you not make the dealership fix the blatant production/delivery mistake - once you go DIY they will have their out re warranty repairs!

That said, I totally empathize not having to deal with techs at the dealership though and who knows who (in respect experience) you'd get assigned to remedy the mistake.

Go slow with the grinder !!

Agree in principle. If theyd change the inserts to proper ones ok, but Iam convinced they will just grind themselves and given they didnt even figure out the main issue after 2 attempts I dont feel too confident. Btw my grinding gear is a little heavy duty but my wife has some nice little thingies for nails and stuff - will give that a go

 

[ciaranob]

Agree in principle. If theyd change the inserts to proper ones ok, but Iam convinced they will just grind themselves and given they didnt even figure out the main issue after 2 attempts I dont feel too confident. Btw my grinding gear is a little heavy duty but my wife has some nice little thingies for nails and stuff - will give that a go

Hear you - I use a Dremel tool for that type of mod (recent ashtray conversion to mag charger) and works like a charm.

 

[Bao1303]

My Dremel equivalent is broken hence the nail thing. ?

 

[Bao1303]

Main reason for posting this is due to the observed design. Had a look inside left door as well and same issue, however the remaining plastic bits seems a bit lower so the membrane just clears it with aprox. 1mm. Given the small clearance and relatively rough molding, I am pretty sure others will have the same issue but maybe confuse it with panel resonances.

 

[Cowtownhusker]

Is the piece of plastic solid or acoustically transparent/fibrous?

 

[Vercingetorix]

Is the piece of plastic solid or acoustically transparent/fibrous?

I wonder if they can have acoustically transparent, yet water resistant material all in one.

 

[Bao1303]

Is the piece of plastic solid or acoustically transparent/fibrous?

If you refer to the lower picture, the "disc" is solid, and squeeze against the membrane creating terrible distortion (although muffled as the disc is not transparent). The upper pic is how it should be, as confirmed by my left door. I dont know why that snap - off disc is there at all - maybe for other configurations than the burmester system

 

[Bao1303]

So, finally did all 4 doors as issue was present on all of them. Grinded down all protrusions - and voila massive improvements. Not sure if I have a "monday car" but suspect lots have the same issue. Not sure if Bose has the speaker in same location but if they do they may have same problem. Still the door panels are not damped enough but for "normal" volumes its quite good now

 

[Propofoln]

Did this take care of the rattling with the bass from the Burmester? Got my Taycan a week ago and the Bass rattling is driving me nuts

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