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A4 Avant (2002, B6) audio questions

firestorm May 30, 2006

  1. firestorm

    firestorm Member

    I have a B6 A4 Avant with the OE Symphony HU 6 disk changer, radio + tape double DIN I believe.

    The sound quality is rubbish. I have just upgraded the front speakers this WE, but it doesn't seem to be enough. I put in a pair of KEF KAR 6.5 woofers with Infinity Ref tweeters, the original KEF tweeters got destroyed in storage :-(

    I had to make some spacer rings from ply, as the original noise maker had a integrated mount.

    I am after a sensible upgrade plan, but I'm not sure where the major problems are.I did the front speakers first as they were cutting out occasionally, due to poor connection probably and I had the speakers from my old golf.

    I'd like to keep the original HU, it looks good in the interior and works with the DIS.
    Is it a major limiting factor ?
    Is it the internal amp that is poor?
    I've read it does have preouts ? Is that 5 preouts? (F,R & sub)

    Is it worth replacing the rear door speakers?

    There is a tiny sub and amp behind the driver side rear quarter panel.

    I assume it is worth replacing that ?
    am I right in assuming I can take the signal feed from the input of that ?

    I have a minimal budget, as I have kids and wifey. I like the idea of AndyMac's stealth sub as a big sub box or even a small bass box in the boot, as it will get in the way of the babies stuff.

  2. AndyMac

    AndyMac Moderator Staff Member Moderator

    As you've already found, just replacing the front speakers will have minimal impact on the sound quality as these are driven off the internal HU amp which is only 2 x 20w.
    The biggest improvement is to replace the rear sub and amp.
    You can fit quite a decent sized MDF box in the lefthand cubbyhole if you don't mind losing the use of the cubbyhole itself. This can house the amazing JL Audio 6.5" sub, or even an 8 incher, which there seems to be more choice on models.
    You'll then need a 4 channel amp in the righthand side (where the OEM sub was) pick up the rear pre-outs & remote on from the original connector and feed 2 channels to the rears (using the OEM wiring) and 2 channels bridged for the sub.
    The rear speakers aren't worth upgrading unless you have very fussy passengers.
    I can't stress enough the difference you'll get just by adding a sub, even a small one, as it takes the strain off the HU. I used a JL sub with an Alpine V12 F400 amp sourced off ebay for £70.
    As well as the above the other limiting factor is the HU itself, I replaced mine with a Blaupunkt DAB54 as I wanted DAB & MP3 playback, but this made a big difference in quality of the source & Bass EQ and meant I could use the 4 ch amp for the fronts and the sub rather than the rears, ensuring plenty of power where it is needed. Also allowed me to replace all the useless Audi pre-out wiring.
    The OEM HU only has front & rear pre-outs (the sub runs off the rears)
    Click here for a full write up:
    B6 Avant Stealth Sub Install
  3. firestorm

    firestorm Member

    Hi Andy
    thanks for the reply.

    have you put a high pass filter on the front speakers so that they have less bass going to them?

    do you have a good source for the jl audio 6.5" subs ?

    do you think it would work well with a smaller enclosure, so that I could keep the cubby hole for the oil n stuff ?

    in summary the bottleneck areas are :

    useless "sub" - replace with jl audio 6.5" sub in box

    next would be the head unit.

    Andy, how do I go about disconnecting the centre channel ?

    Also how do I extract the symphony unit ?

    I assume there is a double din to single din frame and fascia ?

  4. AndyMac

    AndyMac Moderator Staff Member Moderator

    Yes the F400 is hi passed at 120Hz for the fronts, it has 2 built in Crossovers.
    caraudiodirect.co.uk for the JL Audio subs.
    No the cubbyhole has to go, it takes up the entire depth of the big cavity behind the trim, oil can go inside the spare wheel.
    The centre channel speaker is awful (sorry forgot to mention that), you just cut the thin wires on the front speaker ISO connector going to the HU, they are bridged across the left & right channels.
    You need 2 sets of Audi removal keys to get the HU out (Halfords or caraudiodirect)
    I don't think there is an aftermarket standard double DIN to single DIN fascia available, so it's either scrapyard or order the OEM part from Audi dealer as you'll need the whole centre fascia panel. My B6 only had single DIN to start with.
  5. firestorm

    firestorm Member

    Thanks for the help Andy.

    I'll try to get hold of a JL 6W0, the place you mention doesn't seem to stock them any more.

    Just for a laugh, I put in a pair of cheapo Monitor Audio bookshelf speakers in the car. Wrong impedance and all that ... but it sounded much better :-(

    Must be the enclosure I think.

    I'm in two minds about messing with the HU, for 3 reasons

    double DIN to single DIN
    Looks of a non OE HU
    Cost and complication

    I've looked on a couple of other forums and noticed a few people wanting to go the other way - single to double DIN, so that they can use the Audi Navigation. I might see if I can so a swap with someone to retain the OE dash look.

    As far as the HU is concerned, I haven't seen any that look the part and have the functions that I'm after so that I can justify it to the BOSS.

    Becker units seem closest so far.

    I'd like to be able to

    1) play mp3 from a USB memory stick or even better USB HD.
    2) Have a decent radio with good reception and good interference rejection (I have fitted 3rd party HID high and low beam)
    3) Bluetooth handsfree
    4) Have decent preouts, 4 channels +sub
    5) Have adjustable high pass filter so that I can use the internal amp to power the rear speakers, but cut the mid and low bass.
    6) Ipod connectivity (I haven't got one yet, but can replace option 1)

    Not too much to ask for ? It doesn't even need to play CDs!
  6. AndyMac

    AndyMac Moderator Staff Member Moderator

    I'd stick with what you've got and buy a Phatnoise for MP3 hard drive playback then upgrade the sub.
    You don't really want a USB stick sticking out of the front of the HU, not that anyone supports USB on a HU anyway as far as I know.
    My DAB HU supports mp3 playback from SD memory card, but you're limited to 1GB at the moment, but that's still around 30 CD's which is more than enough for me

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