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No sound from rear speakers after new HU

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Bramley, Mar 2, 2013.

  1. Bramley
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    Bramley Member

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    Just fitted a new head unit but now I have no sound from the rears.

    Any ideas?
    #1
  2. dany2k
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    dany2k Member

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    You'll need an adapter which can be bought from pretty much any car audio store... had the same issue with my long-gone A3 8L years ago.
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  3. TDI140
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    TDI140 Well-Known Member

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    I was told by an auto electrician that fitting a new head unit to an audi a3 isnt as simple as straight swap over due to the rear built in sub and the rear speakers best option is take it to someone who knows what they are doing, i decided to stick to standard for the time being because i cant find a second hand double din unit to buy and RNSE unit and fit it in
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  4. Sidhu88
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    Sidhu88 Active Member

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    What year is ur car?
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  5. Rom
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    Rom Member

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    As said, need an adaptor.

    Fitting the headunit is easy....as long as you dont want to use original speakers lol.
    #5
  6. nige.m
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    nige.m New Member

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    hi. I used a canbus adapter on to the quadlock and use the live feed that powers the aerial on to the sub feed cant remember everything at this time. my post may be in the aufio section.
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  7. Digzz
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    Digzz "Started From The Bottom"

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    You will need to Re-wire the rears to the front as the oem Sub + Amp powers the rear speakers.
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  8. NHN
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    NHN Modmetractor

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    Well 1st question I'd ask is what head unit is it, you need to provide as much info for help as possible, saying I just fitted some wheels, but they dont turn doesnt help, you need to say they're 18 inch, ofset etc, width etc, if you get the analogy :)
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  9. nige.m
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    nige.m New Member

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    Try posting in the audio forum. You dont need to rewire anything. It will work from the geed you just need to balance the sound ss the rear may be quite.
    #9
  10. Bramley
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    Bramley Member

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    I have got a canbus adapter on the quadlock adapter.

    It is a 54 Reg.
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  11. Sidhu88
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    Sidhu88 Active Member

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    U need to wire the remote to an ignition and not the power antenna. The power antenna will only work whilst the radios on, every other non radio function wont put any audio out cos the power antenna wont be on.
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  12. Bramley
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    Bramley Member

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    Is this ignition wire going to be on the HU or Harness?? or do I need to track one down??
    Sorry not that clued up on this.
    #12
  13. ScottD3
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    ScottD3 I want your faulty electronics

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    Still no idea what stereo it is that you are fitting to your car.
    With or with out Bose?

    I know the cars are slightly different but people said all the above about fitting a new stereo to the B5 but it was all balls in the end, you can still get music from the rears while using the normal speakers and amp. Just a little bit of wiring behind the stereo.
    Blue remote cable went to power the amp up and the amp line in feeds went to the speakers out from the stereo, sorted.
    But this depends on the stereo you are fitting.
    If its a Audi unit, then it should be pretty simple depending on bose or not.
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  14. Bramley
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    Bramley Member

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    It is an Xtrons Audi A3 unit. Non bose
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  15. ScottD3
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    ScottD3 I want your faulty electronics

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  16. Bramley
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    Bramley Member

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    Thats the one
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  17. Sidhu88
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    Sidhu88 Active Member

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    Can u take a pic of ur wiring harness? Both bits, the adaptor and the harness that came with the stereo? If you haven't got the connects2 lead u may need to wire urself an ignition source (i've put a guide up for it on here just search for it).
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  18. Bramley
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    Bramley Member

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    The HU itself does come on with the ignition, so how come the amp doesnt? is this because it is a loose wire and not connected to anything???
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  19. ScottD3
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    ScottD3 I want your faulty electronics

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    The amp I powered on by the head unit.
    If you keep the ignition on and turn the stereo off, you can sometimes hear a click of the amp turning off (On the B5 any way).

    The stereo normally sends a remote signal to the amp to turn on.
    If the stereo is not sending that signal, it wont turn on.

    If you find the remote feed to the amp from the original wiring and wiring in the remote live from the stereo to the original remote wire, it should turn on but you still might not have rear speakers are they are feed to the amp from OEM's Line out feed and not normal speaker feed.
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  20. Sidhu88
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    Sidhu88 Active Member

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    As scottb5 said the amp comes on with the remote and uve got ur remote connected to the power antenna rather than an ignition source. Connect to ignition source and this should overcome ur issues, if it doesnt then u may have the wrong harness adaptor
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  21. Bramley
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    Bramley Member

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    K brill, ill have a go and let you know.

    My radio reception is **** aswell, any ideas how to overcome this??

    As you can see in the picture, this is the adapter it came with

    [​IMG]
    #21
  22. Sidhu88
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    Sidhu88 Active Member

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    So u kno the blue cable thats loose on the aerial part, is that what u connected the amp wire to? I can see a "p. ant" wire on the main loom, u need to attach that to the aerial adaptor, this gives the signal booster thats built into that adaptor its power which will give u the signal strength u need for good reception. The original stereo has one built into the unit, every aftermarket unit i've installed has needed adaptors.

    As for the issue with the amp, if this is the exact lead u got with ur stereo as pictured then it has no connections for the amplifier built in. If u look at the original block there will be two slots at the top with one or two blocks slotted in. e.g. the blue and green pictured here
    [​IMG]
    These are where the connections need to be made for the amp. This lead basically bypasses the need for a harness adaptor. Normally u got from quadlock to iso to manufacturer loom. This goes straight from quadlock to manufacturer so u can't adapt it in the same way.

    All is not lost however, i'd defo advise u get someone to do this for u, but u could buy a high to low level RCA convertor and convert all ur high level rear speaker outputs (green, green/black, purple, purple/black) to low level rca outputs, create a new remote for the amp, and u shud be able to do it that way. Saying that, i installed a similar unit to this a few weeks back in an x5, and one not long ago in a focus and both had an adaptor with the RCA inputs that could be plugged in if needed. U could use that instead if u have it
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  23. Bramley
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    Bramley Member

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    Yep thats right, the blue nd green slots at the top go into nothing.

    Ok I am not to clued up on all this so I will have to do some research
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  24. Bramley
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    Bramley Member

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    I did get RCA connectors I think - The things that look like AV Cables??

    by saying the aerial adaptor do you just mean the standard aerial plug that goes into the back of the factory stereo?
    Last edited: Mar 7, 2013
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  25. Sidhu88
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    Sidhu88 Active Member

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    Ill show u in more detail when im home. In the meantime have u tried contacting the company u got it from to see if they have other options on the leads? If not, in all honesty i reckon ud be better off gettin a refund.
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  26. Bramley
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    Bramley Member

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    Ye I have and they were no help whatsoever - chinese! they suggested I take all the connectors off and just wire them together.......

    Refund not an option.

    So what would I need to do if I got aftermarket sub nd amp?? how you go about re wiring the rear speakers in?
    #26
  27. Sidhu88
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    Sidhu88 Active Member

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    Y isnt refund an option? they've given u a product that doesnt work as its described to. Being shaped to fit an a3 it shud be sold with the correct lead to make it work in an a3.

    Ok if u want to go about getting this sorted anyway u have two options. Stick with the original equipment and adapt the wiring to allow it all to work. Or buy aftermarket equipment. I think adapting the original will be easier. I didnt realise before hand but u wouldn't need an rca convertor for OEM equipment, only for aftermarket (sorry about that, i was pretty tired and not thinking straight)

    Anyhow, adapting oem would be as follows:

    Audio input -

    Locate the green, green/black, purple, and purple/black wires on ur stereo loom. Ud have to cut these and connect to some extra wiring thats long enough to go through the car and into the nearside section in the boot (about 5m is usually enough). I recommend using bullet connectors for all the necessary connections. U'll need to remove all the panels necessary to gain access to the sub in the boot. U'll then need to locate the connection plug for the amp (should be blue, use andymac's guide for identifying wires) and then cut and attach ur new wires to the necessary inputs on the plug (again using bullet connectors). This provides ur audio input to the amp which will then be amplified and sent back out to the speakers.

    Remote -
    U'll need to find an ignition source which will turn the amp on and off. Preferably with one connected to the stereo, which will be the red cable on the loom. Again, attach to the stereo wiring harness, run a length of cable to the rear (preferably blue, thats the normal colour for the remote) and then attach that to the remote input on the amp. This is unless there is already a remote output on the stereo harness but i can't see one.

    Potential problems with this are that the inputs for the amp may not use seperate positives and negatives for each channel but instead one left positive one right positive one ground as opposed to a left positive and negative and a right positive and negative. If this is the case u'll have to run both negatives to the single negative on the amp input. Another problem is that the ignition switch u need for the remote may be too high a power output to run through the remote input (not sure what the original is, but on most aftermarket looms the remote output is 0.3amps). This may cause poor grounding issues which will result in a whining sound through the amplified speakers.

    If you go non OEM -

    U'll need to buy an amp that will allow u to power the sub and rear speakers. U'll need to wire in all the necessary wiring to go with, connect the RCA's to the rear channel output and sub outputs. U'd be better off going with an aftermarket sub, again it might be worth checking andymac's guide for replacing the original sub with one of the ones he suggests. or u can take up bootspace with a sub/box combo. The difficult bit will be running new wiring to the rear speakers. I'm not too sure what gauge the original cables are but they'd probably be too thin to cope with the power of the new amp. I dont think the OEM one is all that powerful, and most aftermarket ones are. U could just connect to the speaker outputs from the amp plug but u may be risking burning the wiring out.

    Pretty sure that should cover it, although it is 1.36am atm. If ive forgotten anythin i'll reply tomoro
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  28. Bramley
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    Bramley Member

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    You know your stuff dont you Sidhu! Thanks alot, I think I'll stick with OEM, although I really like AndyMac's stealth sub.

    Surely it'd be easy enough to wire rear speakers to HU and then have the aftermarket AMP power it all??

    Thanks for all your help tho!
    Last edited: Mar 8, 2013
    #28

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