2009 Audi TTS Coupe (Bose) - Subwoofer Upgrade

[MaXius]

If you ordered the Bose in your TT, and were disappointed, you're not alone.

Especially the subwoofer, I mean, really... a 13cm sub?
So I decided to replace it.

I'm keeping the standard head unit, Bose Amp, speakers, and just replacing the subwoofer (driven by a new amp).

Specs

Memphis 15-SC12D4 500w Shallow Subwoofer
Alpine PDX 1.600 Monoblock 600w Amplifier
MTX Re-Q5 (Head unit doesn't have sub pre outs, just 4 speaker channels)
Custom made sealed sub box.

Installation

Everything's on order, so in the meantime i'll create the box for the sub.

First step... dynamat the whole boot area.



Then cut out a decent space from where the spare tyre would go (if you didn't have runflats), and mask it all up with tape.



Then put your mold release layer of foil (or glad wrap) on top of that.



Next step, fiberglassing! Start off by putting a couple of layers on, and let it harden overnight.
I made up my resin in 500ml lots. (1% MEKP, 5ml to 500ml resin) Make any bigger quantity, and you'll have to work really fast.



It was a real pain in the butt to get out, my release layer didn't exactly work. So I filled the box up with ice/water, (for shrinkage) and got a good grasp and PULLLLLL. It came away in one piece.

Trim up the edges, and use some 80 grit sandpaper to rough it up for the next session.



Clean up all the masking tape etc until your boot looks spotless again.



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That's as far as i've gotten so far, waiting for all the bits to turn up, but will do some more fiberglass layers in the meantime. Stay tuned!

[thormxkid]

lookin very good

[SSCustoms]

Interested to hear how you like the Memphis sub.

[jorgegarcia]

This is relevant to my interests

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How are you planning to attach the sub baffle to the fiberglass tub?

[MaXius]

Once I finish the layering, I have some dowel i'll glue in there to keep the MDF at the right height, then i'll insert the MDF, then fiberglass over the outside edge, then milkshake around the inside.

[kota_sounds]

red glass?

[MaXius]

Originally Posted by kota_sounds

red glass?

Looks better than 'natural' brown. The resin shop has it in little tubs.

[MaXius]

Ok, well I did a bit more fiberglassing;

Added another layer over top of my rope reinforcement.



And then another layer. How many layers is enough? I can do this now...



Oh and guess what turned up on Xmas Eve... yay! Thanks Santa!

[kh971]

I am interested in the sub's performance also.

[rollininstyle2004]

Looks great so far!

[MaXius]

Today, I did the final layer of fiberglassing; I thought.. what's one more? :P

While waiting for that to dry, I started on the MDF.

I marked it out where I should cut, then went the hack with my router.



Because I indented the sub 8mm, I wanted to reinforce behind it, so I made a 6mm spacer and glued that on.



After that dried, I marked out my drill holes for the sub.



Then I drilled them, then put some T Nut cabinet fittings on the inside so it's easy to bolt the sub in (without stripping the MDF).



Then for a quick look-see, I whacked the sub in with a couple of screws. Yeah babyyy..

[yellowcard]

Very nice!

[orangelss]

That ReQ is a nice piece. Have used a couple and sold one on here a little while back.

[MaXius]

Ok well I made the most of my Xmas holidays, (all 3 of em) by cutting down the fiberglass enclosure to the proper height I needed, then hours of fiddly sanding to get the MDF to insert properly into the shape of the box.



Then I cut some dowel to size and glued them into the box, so the MDF will rest on those (as well as the rage/resin seal i'll put around the inside edge and the layer of fiberglass over top when I go to seal it up).



Now i'm waiting for the postie to deliver the rest of the crap I ordered so I can continue...!

[Dave Holmes]

Excellent work so far. I'm very interested in the end result of adding a sub to a Bose system. Mine doesn't even have one, and the wife's has a little 8 inch one. I'd like a little more, yet not go overboard on a huge box in the trunk....

[FLYONWALL9]

Really nice work! The only thing I would worry about
would be that 5min epoxy and those dowels. I wonder
if its too brittle with not enough flex for this application.
Something like 3m 5200 is way strong enough with lots
of flex. But hey, only one way to find out.

I REALLY do like your glass work though sir! Some of
the best I've seen on this forum.

[MaXius]

Thanks for the kind words, the 5 min epoxy will be fine, when I put the lid on i'll be liquid nails-ing it to the lid, not trusting the epoxy by itself.

[MaXius]

Seeing as I can't really do much more with the sub box, I decided to pull the crap subwoofer out, to see if my amp can fit in its place.

OH MY GOD, it's PLASTIC! Also, the speaker mount for the rear (and probably all) speakers is PLASTIC too! That really gives me the sh1ts... nasty stuff.



ANYWAY, out it goes! I took note of the mounting points, and cut out a piece of MDF so i'll have something to screw the amp into. The amp JUST fits when you put the trim back on, luckily I didn't get the JL I was contemplating.. lol.

I'll have to make up a couple of joining sleeves because the screws are mounted in the body, and they're not long enough. So i'll get some rod and bore it out, then tap a thread through it.. that should work.



At this point I noticed a pretty sturdy looking lug where the sub was mounted into the frame. GROUNDING POINT!



So I filed the paint off, ready. My ground wire is going to be all of about 6 inches.. lol!




Then it was on to the wiring. Bose systems are normally pretty weird.
I managed to get a wiring diagram, and from that, traced which wires were coming from the head units, and what they were for.



It was actually quite straightforward, surprisingly. Previous versions of the Bose system in Audis' have been quite the PITA.







This version doesn't even look as if it's got common line-out ground! (another quirk they usually have)



So now I need to wait for the stuff from the postie, then I can do a whole lot more.

[Topdown]

lookin good... love the red glass

[MaXius]

Tonight I made a little bracket so I can mount the ReQ5 onto the wheel arch, inside the rear quarter cavity (where the Bose amp lives).



The fun part was working out how to do the wheel arch curve. I bent some strips of metal around to make a bracket, which I mounted a couple of squares of MDF in the middle of to suit the standard ReQ mounting points.



I could have used MDF to fabricate a whole bracket and blah blah blah, but no one will see this anyway. And it'll work just as well, if not better (suspension, vs rigid)



I'll glue a couple of strips of velcro to the underside and to the wheel arch rubber/dampener, and it'll hold in fine.

[danteg]

Nice build !!! I can't wait to hear you comments about the memphis sub !

[CJtech323]

Wow looks nice!

[94VG30DE]

Looks great! So are you putting RCAs on the end of those outputs from the Bose head to go into your amp? As I understood it (and in my experience), that Bose head unit is not sending a normal speaker-level signal.

[MaXius]

Originally Posted by 94VG30DE

Looks great! So are you putting RCAs on the end of those outputs from the Bose head to go into your amp? As I understood it (and in my experience), that Bose head unit is not sending a normal speaker-level signal.

You mean line level signal?


Nope, re-Q - Take control of your factory stereo!

It has flyleads on the input which i'll splice directly into the wires in the pic up further.

I'm mainly doing it to get sub-out rca's, as i'm not replacing the speakers.. yet.

From the ReQ it goes to the amp.

[gitmobass]

I'm loving the red glass! I'm going to try that on my next box if possible.