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Fitting set-up from an Audi A4 (B5) into an A3 (8L facelift)

sparx Feb 23, 2009

  1. sparx

    sparx Member


    I recently replaced my Audi A4 1998 B5 chassis with an A3 8L 2001 5 door facelift model.

    OK, so the A4 had a Concert head unit, components speakers in the front doors and powered 6x9s in the rear parcel shelf, all factory standard.

    I replaced the front speakers with the Infinity component speakers (as listed below). The powered rear speakers I left alone as they sounded OK. I then added the Infinity sub and a JVC 12 disc CD changer in the boot and changed the Concert head unit for a JVC one (all listed below), that was about it. I had to buy an adapter for the aftermarket stereo as the rears would no longer work without it. Pretty simple really, minimum effort for fairly decent results.

    So... I now need to put all of this into the A3 (again with minimum effort), which has exactly the same Concert head unit, but has the powered sub in the boot and rear speakers in the rear doors running off that - again all factory standard.

    (Also a quick question regarding the number of speakers in the A3, I can see that there are component speakers in the front doors the same as the A4, but then there are rear coaxial speakers in the rear doors (rather than in the parcel shelf as on the A4) and the A3 has a sub in the boot whereas the A4 did not. There are also some grille type enclosures either side of the parcel shelf, but I can't quite work out if there are any speakers there or not - are there?)

    The equipment I have is as follows:

    Front speakers: Infinity: Kappa 50.7cs component speakers
    Rear Speakers: Infinity Kappa 682.7cf coaxial speakers (6x8")
    Subwoofer: Infinity BassLink Active Subwoofer
    JVC KD-AVX1 head unit
    JVC CH-X1500 12 disc CD changer

    I have also purchased these adapters:

    Autoleads PC9-404 (to run the rears and sub with the JVC head unit)
    Autoleads SAK-1103 speaker adaptor kit (for the larger front speakers) - Yes I know they're ****, but I will make them fit with sealant etc.
    Autoleads PC5-52 (aerial amplifier for the loss in signal from removing the powered antenna feed)

    I think I have just about everything I need to do the job.

    A few questions first:

    I have controls on the steering wheel which at the moment run the Concert head unit - Is there an adapter kit that will make these work with the JVC head unit, or will it just work anyway?

    Do I need adaptors for the rear speakers in the rear doors? As the replacements are 6x8" so I'm not sure if they are a different size. Also bear in mind that this is a 5 door car, so it may be different to the 3 door.

    Both the Infinity speakers are 2 Ohms, does this mean that they may be pulling too much power from the amp? Is another amp needed?

    The JVC CD changer, can that use the existing connections which are running the Audi CD changer?

    The Infinity Subwoofer - again can that use the existing connections which are running the Audi sub?

    I can't think of anything else right now. Basically I just want to take what's in there out and put this lot in. Not interested in building enclosures etc. etc.

    I just need to know that what I have is going to work. I don't want to get half way through and realise I need some other adaptor or extra lead.

    Many thanks in advance, any advice is greatly appreciated.

  2. AndyMac

    AndyMac Moderator Moderator

    The grilles in the parcel shelf are purely for ventilation.
    With what you're installing why on earth are you still thinking of using the puny Audi amp for the rears?
    Wire the rears directly to the HU as the Audi rear amp is 2 x 20w and is shyte.
    You can't use 2ohm speakers running directly off the HU or via the Audi amp (front or rear), it will fry the amp. If you still want to use them then you need to install a 4ch amp that is 2 ohm stable.
    You can't use any other changer with the stock changer cable.
    You wouldn't want to use the Audi sub connection as this runs off the rear pre-outs and you need to run a dedicated RCA off the sub preout on the new HU to give you independent control of the sub.
    You also don't need the PC9-404 adapter. If you still want to use the tiny Audi amp to run the rears which will eventually burn out, the power difference between the fronts running 50w+ and the rears with a puny 2 x 20w will mean you need to fade almost totally to the rear and will compromise the sound completely.
    If you stick with those 2 ohm speakers then you need to run 3 pairs of RCA's, a 4 channel amp and then speaker wiring back to the new speakers. You'll need to run power from the battery anyway for the active sub, so you can piggyback the power for the additional amp. Easiest route through the bulkhead is via the spare rubber grommet near the pollen filter under the passenger side wiper scuttle. This drops down behind the glovebox (which you need to remove).
    Not sure what speakers are in the rear doors, but you will need adapters as all Audi speakers are on non standard mountings. No way will you be able to fit 6 x 8" coaxials in the doors. Apart from the size they will also be way too deep.
  3. sparx

    sparx Member

    Hi AndyMac,

    Firstly thank you very much for the detailed response, it is just what I am looking for. I had a feeling it would be more complicated than the A4 install I put in, which was very easy to do (I am more of a whiz with home cinema than in-car systems).

    In response to some of your points:

    Do you have any suggestions for suitable replacement speakers which I can run off the 50W JVC head unit for both front and back without an additional amp?

    Hopefully of a similar spec to the Infinity Kappa ones (I'll get rid of those on eBay). I presume that 4 Ohm would be better?

    So this is only needed if you are replacing the Audi head unit and just running all the standard speakers as they are now?

    This means then, that I can simply replace the Audi head unit with the JVC one and not worry about any kind of adaptor as long as I am going to wire the rears directly to the JVC HU?

    OK, so the speakers in the rear doors I presume are still going to be coaxial ones as I can't see any grilles for the tweeters in the rear doors.

    Also the grilles in the rear doors are wider than in the front so this would suggest they are not going to be the same as the 4" speakers in the front.

    Anyone know what size the rear speakers are?

    If I have time at the weekend I may take the rear door panel off and have a look, but if someone knows and can save me from dismantling my doors it would be greatly appreciated.

    Finally, from what I understand in your reply, this isn't going to be as simple as slapping in a new head unit, replacing the front, rear, and subwoofer speakers and CD changer then away we go?

    Whatever happens I need to re-wire the rear speakers directly to the head unit at the front. Take out the Audi sub and eBay it, run power from the battery and put the powered sub in the boot, put new wiring in for the CD changer (taking out the old), run everything off the JVC HU and then I should have a fairly decent sound?

    Once again, thanks in advance for any replies.

  4. AndyMac

    AndyMac Moderator Moderator

    Yes 4 ohm is standard. Depends on your budget but I wouldn't spend a fortune as the quality you'll get from the front doors is severely restricted by the flimsy door card they are mounted to and the tiny space they occupy. You just need 5.25" slim components (no greater than about 54mm depth). Rainbow 230slx's work well, as do the DLS RS5 slimline, but a bit pricey.
    The rears can be anything you like, most coaxials are 4 ohm.
    I'd leave the sub in place and the changer cable, as you can then easily go back to stock when selling the car. they're worth very little and the sub is a pain to remove.
    You don't need any wiring adapters (apart from the aerial amp) as long as you rewire the rears directly to the HU.
  5. sparx

    sparx Member

    Excellent, thanks for that!

    Only one last question, which may be a bit more tricky. The controls on the steering wheel for the stereo - Will they still work, is there another adaptor needed or am I just going to lose them?

    I have seen that the upgrade to the JVC head unit I have, the JVC KD-AVX33 has a feature which means it can be compatible with steering wheel controls. Maybe worth upgrading if I can keep this feature?


  6. sparx

    sparx Member

    Quick update, I've managed to answer my own question. It appears that the JVC unit I have also supports steering wheel controls when used with a JVC adaptor which costs about £5, so problem solved.

    Thanks again AndyMac for your advice.


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