Sound Deaden the subwoofers and surrounding rear trim panel

fmorelli

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[This is a rescue thread from the UK z4-forum. Much like the Photobucket debacle, postimage.org made a change that killed all the links to its repository. After repeated requests by several z4-forum members to get this fixed, the author nor anyone else seem to address it. Thankfully I had the information and have recreated the thread here, to protect availability of the content. It was originally created by billy_beemer, who as of this posting, had not logged in to the z4-forum for two years.]
 

fmorelli

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Aug 11, 2017
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E89 Z4 35i, F10 535d
I have the 11 speaker setup, to start with I thought one of the subs was blown, but mainly the farting noise of the stock subs comes from the surrounding trim (at least on my car it did)...

As I couldn't really find any concrete documents on the wattage and resistance of the subs (which I know at least are 2 ohm and probably 30-40watts RMS) I felt it best just to have a go at applying some good old Dynamat to try and resolve the problem..... and it seems to have worked quite well, more punch to the subs and less farty noise.... almost no farty noise in fact..... not bad for an afternoons work... as I couldn't find a guide, here's how:

Wind deflector off, prise off the little caps to reveal some screws, pop those out...
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Prise apart the rollbar cover...
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Unscrew.....
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Pull out the weather trim...
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Pull up to remove the kick plate guard, you'll need to remove the rivets and slide them back in to put it back on later...
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You need to unscrew and remove the speaker before doing this part, and make sure you have a small precision flat head to remove the wire connections for the rear courtesy light and the speaker - remember extra care must be taken when using screw drivers near speakers...
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Wasn't 100% sure whether these rivets should be removed but I wiggled this around until it came free
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Remove cheeky bolt (you need to remove the trim nearer to the front of the car to reveal this)
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Pop this off...
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Take a tea break and ponder on whether this is worth while..... of course it is - you're a man, man up....
My pondering took me to a time when I owned an MX-5 and I thought.. the BOSE on the cheap mazda didn't rattle......
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Open the roof half way, remove cheeky rivets - there's one hidden at each end too.
\
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Now the panel can slide free to reveal some bolts, pop those out...
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Cheeky bolts hidden behind the little plastic cover that just kinda wiggles free
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Remove remaining top bolts and you'll find the whole trim panel starts to wiggle free - its held in around the centre console and removing this was a faff, you have to peel back the side covers slightly and work it free - a 2nd pair of hands or even a 3rd would have been a bonus but I managed to do it - you have to be weary as the plastic going into the centre console is dead sharp and will mark the soft leather arm rest...


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Subs! Unbolt, unclip and take inside.....
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4 screws hold in the sub, once removed it took a fair bit of prising to get it out but with care and force (forceful care?) out it will come.
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Now go to town with the Dynamat, I coated the inside of the box, the back of the box, inside the metal enclosure on the car and parts of the bulkhead trim before slinging it all back together.
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Now play some dance music with the BASS up and hope you haven't caused any new rattles in doing all this.

I lost a couple of rivets putting it back together so some spares would come in handy........
 
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fmorelli

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E89 Z4 35i, F10 535d
On my car, exactly. 0.7 lbs per sq ft - I used Noico 80 mil sound deadening. My car has about 10 lbs of that material. It's extensively deadened. I made the decision to do this in part moving to a complete ball joint and spherical bearing suspension, motor and trans mounts, and exhaust, and already being a two seat convertible (not quiet to begin with). My goal is to get to a 600whp track capable car that I can still take a 90 minute drive with my wife and have her not hate it. So had to lower NVH.

Filippo
 
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doublespaces

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Oct 18, 2016
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I absolutely understand this approach. I may consider something like this at some point.
 
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Lurcher

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Apr 6, 2018
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Dallas, TX but soon to be Cocoa Beach FL
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2012 z4
While I understand the deadening of the outside of the enclosure and the car itself - placing any dampening inside the sub chamber just takes away required airspace and adjust the perceived "Q" of the sub (adjusting performance and frequency levels). If anything - some poly batting inside the enclosure "may" help the sub think there is more airspace and counter any standing waves, but as these subs were built for this small of an environment, I'd doubt it.

Of course - this is all theory. Anyone doing this and have a RTA handy? I'm still not convinced this car can be adequately sealed to make a noticeable difference with the top up. This is just adjusting the resonate frequency of the tin can to a different point :grin:

With the top down - who cares....
 
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