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A3 8L Wiring speakers directly to headunit

Discussion in 'In-Car Entertainment' started by DaveA3, Jul 15, 2011.

  1. DaveA3
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    DaveA3 Audi A-Trizzle!

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    [Jul 15, 2011]
    Wiring speakers to the head unit. Sounds simple but how do i do it? At the moment theyre connect via the bose amp (was fully bose before i changed it) i have an alpine head unit and wanna take advantage of it. The bose amp is ****. Is it possible to buy a more powerful 4 channel amp and straight swap it? if not, whats the best way to wire up the speakers? ive not done anything that drastic but have fitted subs etc in the past on other cars and changed the speakers and headunit on this one. Cheers in advance
    Last edited: Jul 15, 2011
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  3. Speedy Steve
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    Speedy Steve Active Member

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    [Jul 15, 2011]
    Its simple either run new wires from the headunit to the door speakers or from the new amp to the speakers. There is no nasty connectors on the door to worry about just a nice rubber tube to pull them through
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  4. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 15, 2011]
    Don't whatever you do wire the Bose speakers to the HU, they will fry the Alpine's internal amp as they are very low impedance (1.5ohm). You need to replace the speakers before wiring them to the HU, or install a proper 4channel amp that is 2 ohm stable.
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  5. DaveA3
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    DaveA3 Audi A-Trizzle!

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    [Jul 15, 2011]
    cheers lads.

    I have some new speakers in there atm, theyre the Edge ones. I have components and rear coaxials.

    Can i simply swap the Bose amp (using existing wiring) for a decent 4 channel amp? or is it a case of stripping it all out and starting fresh?
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  6. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 15, 2011]
    No you can't use the existing power cable, as it is a feeble 5amp feed. You will need to run a 30-40amp power cable (depending on the amp), and I wouldn't use any of the Audi/Bose wiring as it is shockingly bad, I'd run new RCA's front to back. You can pick up the feeds to the speakers from the existing wiring though, but as you have aftermarket speakers then you can run them directly off the HU as suggested above.
    All you need is an ISO speaker harness and 4 lengths of speaker cable:
    Car Hifi Extension Cable : Wiring Accessories : Maplin
    You only actually need the female end, then join the speaker cable to this connector and run the cable to either the speakers directly (need to remove door cards and rear speaker panels) or the Bose amp and pick up the feeds to the speakers from there.
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  7. DaveA3
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    DaveA3 Audi A-Trizzle!

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    [Jul 18, 2011]
    ok cool that sounds alot easier. So grab one of those. plug it into the headunit then run 4 cables to the speakers (females only). Its gonna be easier i think to just run them from the speaker feeds by the amp so i only have to remove one panel instead of 4.

    if i do this i can then just unplug the old crappy amp an get another sub and amp and run the normal way i.e cables to the boot etc.
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  8. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jul 18, 2011]
    I meant you only need the female part of the ISO harness in the maplin link
    So yes you cut the wiring on the adapter (or buy just the female part) and connect all 4 speaker cables to the corresponding cables on the plug (+ve to +ve, -ve to -ve). this plugs into the Alpine then run all 4 cables to the boot and pick up the speaker feeds to the cabin speakers from the Bose harness. I couldn't find any pinouts to the harness on line, so you may need to use an AA battery across the various connections to locate the right wiring for each speaker (each one will pop very slightly when you have a pair). You then won't know which is +ve or -ve without removing the door cards to see if the cones are moving in or out so I would strongly advise trying to find the pinouts on the Bose connector before starting the job as it may be easier rewiring straight to the doors.
    Adding an amp & sub is just a case of running an RCA cable and power in the normal way. Essentially you've bypassed all the Bose stuff so it's all straightforward from there.
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  9. DaveA3
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    DaveA3 Audi A-Trizzle!

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    [Jul 19, 2011]
    excellent once again full of help, cheers mate!

    now i just need to find those pinouts on the bose connector. Any clues anyone?

    Many Thanks!
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