A4 Avant (B6) Stealth sub install

AndyMac

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After such success with my A3/S3 stealth subs I thought I'd give it a go in the Avant (that has now replaced the A3T).
Although the sound in the Avant is not has horrendously bad as the A3 standard "sound system", no doubt assisted by 6.5" speakers all round and this time they have actually bolted them to the doors rather than loosely screwing them to the hardboard door cards, it is still in need of a lot of attention.
After upgrading the HU to a DAB radio (Blaupunkt Woodstock) and rewiring the rears to the HU rather than through the feeble amp, I thought it was time to AndyMac the sub.
Knowing how long it took me to do the A3 I wasn't looking forward to it, however it turned out to be much easier. There's absolutely loads of room behind both the left & right boot trim, and no need for any fancy curves like the A3.
Also you don't have to remove half the interior to get the trim out.
After removing the feeble plastic sub and amp I decided to mount the amp on the right, and the sub in the unused space on the left. There is quite a bit more room on the left (no fuel tank) and just enough space on the right for a decent sized amp. Plus the wiring is there already as at this point I didn't want the hassle of running seperate RCA's.
Running power is relatively easy via the ECU down into the footwell and tucked under the door trim & into the boot.
The sub enclosure was really straightforward, just a 17" high, 7" deep 18mm MDF box with one side angled from 8" at the bottom to 12.5" at the top. Lined with speaker wadding and front loaded with the incredible 6.5" JL Audio sub.
The enclosure just drops straight in and there's even a spare bolt hole in exactly the right position to secure it in place.
One painful decision was to have to cut away the back of the cubbyhole, but I did it in such a way that it could be hotglued back on at resale time.
The transformation is extreme, probably better than the A3 version as the enclosure is a lot bigger. I was gonna try an 8" driver as there's plenty of space for it but I really think there's no need.
Anyway here's the all important pics:
AvantRHSSpace.jpg

AvantLHSSpace.jpg

AvantAmp.jpg

AvantSubbench.jpg

AvantSubinstalled.jpg

AvantSubinstalledtrim.jpg

AvantOEMSubbench.jpg


I also discovered that the Avant has had a rear end prang at some point (wondered why the rear no. plate was from Listers bodyshop).
The enclosure shown is just the rough version to prove the concept, I'll get round to sanding and painting it at some point.
 
Great bit of info.. i'd just looked at the photos of the original stealth sub and thought damn its for the A3 and then this appeared! Been lurking and reading for a month or so, just bought a 52 reg a4 avant 130 so very relevant.
did you run speaker caable to each rear door from the HU and if so is it straightforward?

would you drive with the door down on the sub? does it rattle with the sub on?
 
No I cheated and ran it to the original sub and picked up the rear speakers from the rear amp.
Surprisingly the rear cubbyhole door doesn't rattle. I was thinking I'd have to cut a hole in the door or have the door open but I guess because it's such a loose fit theres nothing much to rattle. I did have to make one modification as originally the sub would actually make contact with the door with the volume jacked up (the cone was extending so much it would vibrate on the door), so I just used a router to sink the sub into the front of the enclosure by about 8mm. Ideally I should have made the enclosure slightly less deep so it isn't as close to the boot trim. I've also ordered some dark grey carpet which I'll glue to the enclosure so that it fills out the hole behind the door as it does look untidy with the door off.
 
Also I fitted some Alpine components to the front doors at the weekend and what a difference that makes!
The OEM speakers sounded really harsh at higher volumes, but the Alpines sound sweeet.
They were a doddle to fit as well. I just made 2 adapter rings from 18mm MDF, and a fitting ring from 6mm MDF, glued and screwed the whole lot together to give the required depth needed for the mid woofers. The tweeters just slotted straight in with a bit of double sided foam wrapped round them.
All that's left to do is install a 4ch amp in the boot (rather than the current 2ch sub amp) and I'll run RCA's from the HU and have 2ch's bridged for the sub and the other 2 running the fronts.
 
Installed the 4ch amp today and wow what a difference! Combined with the sub and the new front components the sound is drastically transformed.
No interference either which was a major concern as the Woodstock DAB54 uses the ridiculous Audiesque mini ISO plug for the pre-outs (not fully screened).
I had to reposition the Audi alarm/horn in order to fit the bigger Alpine V12 F400 in the right cubbyhole, but everything else was straightforward.
 
Fantastic work Andy - You've answered my question from a few weeks back Here.


As soon as I get my new garage built (start this week) I'll be on the case!

BUB /ubbthreads/images/graemlins/beerchug.gif
 
Just disconnected the centre speaker speaker in the dash and wow what a difference, it seems to have been chosen purely to provide all the harsh treble, middle & distortion in the car. It actually runs bridged across the 2 front speaker connections, so was comparatively louder than the front components.
all sorted now. Here's the 4ch amp squeezed into the right cubbyhole, you've got about 11 inches of width here so pretty accomodating of most amps (need to tidy up the wiring though):
AvantAmp4ch.jpg
 
Wow, thats cool.... I have just purchased a Audi a4 B6 avant tdi130, I was wondering do you do these installs for anyone thats interested? Thanks
 
Okay, Im interested, how much? oh and what part of the county are you from? Cheers
 
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Very interested in this as well

After a sub/amp boot combo