Author Topic: The (semi) non-destructive rear speaker installation  (Read 638 times)

ptashek

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The (semi) non-destructive rear speaker installation
« on: 06 September 2017, 06:56 PM »
I've finally gotten around to installing the rear speakers I got for Goldie about a year ago. Below is a short description of how I have installed a pair of Infiniti 5002ix 13cm speakers, without cutting or drilling any holes in the chassis. The only element that was modified was the parcel shelf, but in a way that - at least for me - looks great, and as if it were this way all along.

The first problem I've come across was the shape and size of the speakers, which immediately made the OEM chassis openings to small. These are made for 10cm speakers.
The second problem was the mounting hole pattern, which, in true Mercedes-Benz fashion, is entirely different from what everyone else used - three holes in a triangular arrangement, as opposed to four in a cross arrangement.

Since my parcel shelf is already custom made - cut from 3mm MDF and covered with high-pile fine velours carpet - I have decided to modify it in a way that would let me install the 13cm speakers, while using the original 10cm openings. To that end, I've laser cut adapter rings from 3mm plywood, with 158mm/122mm OD/ID, and them made a test fitting to figure out how many I'd need per speaker. The optimal result was five, for 15mm total adapter height. Adding to that 3mm for the MDF and 8mm for sound proofing matt under the parcel rack, the total distance to chassis was 26mm. That raised the speakers enough for the widest parts to clear the chassis opening with room to spare.

Next, I've glued five rings per adapter with PVA glue, and - when dry - cut the carpet around them so that they'd rest against the parcel shelf MDF. I've chamfered the lower edge, so that the ring would fit in a slightly smaller diameter hole, making the carpet fit snug around it when installed. That worked really well, so I've glued the adapter rings to the MDF, then trimmed the 10mm openings pre-cut by my restorer to fit the internal diameter of the adapter ring. Basically, now my parcel shelf has built-in speaker pods :)

After re-installing everything, the entire setup looks and works really well, albeit I don't fancy removing that at some point (hopefully not in the next 40 years! :)), as there's very little space to work with any tools there. I've left the adapter rings unpainted, just sanded them down and waxed with pure bees wax, mixed with turpentine and linseed oil. That gave the plywood a nice, subtle sheen and made the texture pop. Thanks to how the laser beam seared the cut edge, it looks quite close to the original zebrano trim, which is an added bonus.

Here's some pics :)

Raw adapter rings after cutting


Parcel shelf carpet pre-cut to original chassis dimensions


Adapter rings glued together and getting finished


Finished adapter ring in-situ, glued into the parcel shelf


Test fitting of speaker, to mark where mounting holes need to be pre-drilled


Finished look


...and a short video showing the whole thing, before final assembly, in action: https://youtu.be/C6JpbDmlCAg
« Last Edit: 06 September 2017, 07:03 PM by ptashek »
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floyd111

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Re: The (semi) non-destructive rear speaker installation
« Reply #1 on: 06 September 2017, 07:26 PM »
wonder about shakes in the first-aid compartment. Any?

I would also like to see other forum member's hifi setup. There may be more ideas there.

ptashek

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Re: The (semi) non-destructive rear speaker installation
« Reply #2 on: 06 September 2017, 07:39 PM »
wonder about shakes in the first-aid compartment. Any?

None, thanks to the sound deadening matt under the shelf.
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Squiggle Dog

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Re: The (semi) non-destructive rear speaker installation
« Reply #3 on: 06 September 2017, 08:26 PM »
Very nice idea! I think I have seen people mount a subwoofer in place of the first aid box, too.
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Diesel 617

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Re: The (semi) non-destructive rear speaker installation
« Reply #4 on: 12 September 2017, 09:06 AM »
That is an awesome idea! Way better than cutting the metal (talk about a pain). I was thinking of doing something to fit 6X9 speakers back there, I like the idea of raising it like that. It looks clean and professional, very nicely done, bravo!
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