Working on an install in a new-to-me 2009 A3 8PA. No previous modifications have been done to the car. The factory receiver is the Audi Concert with Blaupunkt component speakers. There's a tiny subwoofer in the trunk with an enclosed amp.

Is this a Concert III or a II+? Also, I'm not sure if this is a Bose system, but it seems like it is. How do I tell? Photo of similar deck is attached.

From what I gathered so far, it seems like the deck powers the front high and midrange. Then there is a line level output to the amp in the subwoofer enclosure. The amp powers the subwoofer and the rear speakers. Is this true? My shot at a diagram attached.

The main goals for my project are a) great sound at a budget price and b) as little visible modification to the car as possible. I have a bunch of older components which will help keep new investments to a minimum. But am starting to worry I'm on the wrong path.

So far, the High-Level Plan: Keep the Audi Concert head unit. Install a 4 channel amp in the trunk to power 2 sets of component speakers. Hang an additional 2 channel amp off of first amp to power a small sealed sub. I'm not an expert by any means, but I have installed a few stereos before.

Foreseen Challenges: 1) Mounting tweeters in the front column factory location looks to be messy. I don't have a lot of tools for custom pods. Suggestions here are much appreciated. 2) Have read that there's no turn on lead to the Concert receiver, and that the best alternative is using the one that leads to the subwoofer. Great if true, but not yet verified. 3) Want to mount the second amp in the factory subwoofer location. Will be interesting to see if and how it fits behind the carpeting.

Detailed Plan: Use the Schoche SLC4 high-level line converter at the receiver to allow a 4 channel RCA (Monster MPC I404 4C-5M Extreme Low Noise) to connect a US Acoustics 4085 (480 x 2) amplifier. The amp will be mounted on the back of the right rear passenger seat and will power two sets of components. In the front, Infinity Kappa 60.9cs. In the rear, Infinity Kappa 60.2cs. Use a 2 channel RCA (Monster MPC I402 2C-2M Extreme Low Noise) to connect an Alphasonik 2075 (150 x 2) amplifier. The Alphasonik will be mounted on the left wall of the trunk space, behind the carpet mat (hopefully - otherwise, above the US Acoustics on the seat back). In bridge mode, it will power a single JBL GT Series Power 8" subwoofer in a sealed enclosure. The box will sit (velcro) on the floor of the trunk for easy removal when hauling stuff.

A diagram of what I think this will look like is attached.

 

After reading more, this rear amp seems to be challenge to work around. Do I need to use it to get proper speaker level output? What is the difference between Bose mode and non-Bose mode and how do I control that? Do I need to control it? Should my setup look more like the attached diagram?

Thanks for any and all assistance.

 

Seems like this is a Concert II+, because it is 2 DIN.

After looking at the pinouts (attached), I see that I have line level output to the rear AND front. I also see 4 N.C. marked pins near the speaker level front connectors. Are these speaker level connectors for the rear?

If I use these, perhaps my first diagram, with the 4 channel speaker level to RCA converter at the receiver, will work. And skip the factory rear amp completely.

Thoughts?

 

Even better, maybe the line level outputs will provide a better signal? In this case, I'll use the line level outputs to the scosche adapter.

 

To answer some of the questions in my previous posts.

This is a non-Bose Concert II+.
The deck powers the front component and center speakers.
There is a separate amplifier for the rear speakers and subwoofer.

There is a turn on lead that goes from the Concert head unit to the rear amplifier, but the head unit itself uses the CANbus to turn on and off. The turn on is the white wire on pin 9 of the connector. See picture.

New diagram attached.

Mounting tweeters in the A pillars was easy, once I removed the seat from the factory tweeter. The seat, nicely snaps into the factory speaker baffles. I used epoxy to fasten the 1" tweeter to the seat, then snapped it into the baffle.

Mounting an amp in the factory sub location was easy. Since I'm not using the sub or the amp, I just pulled it out and fit my new amp in its place. There is plenty of space for my two channel Alphasonik.

The line out converter is out of the equation. I was mistaken to think it could be connected to line level wires.

Instead, I got a little creative with an old set of RCA cables. Since the goal is factory look in the cabin at a budget price, I created a set of line/screen wire to RCA converters. See pictures.

Mounting the rear tweeters was the biggest kluge. The construction around the Infinity Kappa 10.9t is huge. Anyway, I pressed the speakers into the factory tweeter locations. The snap locks put some friction on them but not nearly enough. I added a few epoxy spots where the snap locks touch the tweeter. I also created a rip-stop fabric triangle, which I attached using the hidden trim screws. It covers the rear of the tweeter and holds it into the door.

Tomorrow I'll connect everything but the front door speakers, which still need custom MDF boots like I made for the rear doors, and which you can see all over Audi forums.

Some helpful links:
http://www.audi-sport.net/vb/car-ent...w-audi-a3.html
http://freepdfhosting.com/37841f9301.pdf
http://homepage.ntlworld.com/h5djr/elsawin/
http://forums.fourtitude.com/showthr...?2134080/page1
http://forums.fourtitude.com/showthread.php?4028334
http://forums.vwvortex.com/showthrea...ll-information...

Many thanks to Andy Mac for his installation guide and experience.

 

Hey, thanks for the write up and being diligent to follow up with your findings. I'm doing the same to my A3 and this is going to be really helpful.