[Biturbos4] Fosgate OmniFi for MP3s...

Russ Romano audi at lvahs.com
Sun Jun 12 23:00:39 EDT 2005

About a month ago woot.com had the rockford fosgate OmniFi systems on sale for a ridiculous price... so I got one for each car.  Our Subaru already had an aftermarket headunit and it happened to have "aux" inputs.  Dash had an extra DIN location... System was installed in no time.

The Audi's install was less than easy... but it is done, and very cleanly integrated.  Special thanks to Ti Kan for his help with the headunit pin-outs (I found after pulling it out that the pinout was printed on the top in great detail!  Odd that Audi puts so much information out there, and then creates problems like the following to "hurdles").

Hurdle #1: CD Changer ("aux") input locked.  Needs complex pulse stream to unlock it.  Fortunately K9SPUD, LLC has done a lot of work in this arena and had code for a pic-micro that would do the job.  Program a pic micro, build a little circuit board, and voila, the headunit will change to the "CD Changer input".

Hurdle #2: Audi's OEM CD changers put out double the signal level as conventional audio equipment.  This means that when you connect anything other than an Audi changer to the headunit, it plays at half volume compared to everything else and distorts badly at higher volume because you have to nearly max-out the headunit's volume.  Solution:  Build up a small circuit board with a basic op-amp circuit (x2) to double the output level coming from my generic audio equipment.

After messing with that stuff, the rest was very straight forward...

There is virtually nowhere to put a single DIN faceplate without disturbing the stock dashboard.  I settled on removing the ashtray and placing the faceplate (only 1" deep) in front of that, tilting upward.  It looks pretty good... but if I get ambitious I may make a fiberglass insert for this region, cover it in matching black vinyl and embed the faceplate in that...

If anyone is attempting anything similar and needs a hand with the "signal doubler", etc... just drop me a note.


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