Rear Speakers/Amp not working after new HU
#1
03-08-2011, 02:20 PM
Rear Speakers/Amp not working after new HU
So I recently purchased a new head unit and front speakers for my B5. The rear speakers will not work because of the amp. It's the 4 speaker system without the Bose. I'm looking for how to fix this problem.
1)The audi radio used two speaker signals to power all four speakers, I believe, so im concerned that if I bypass the amp I will lose 100 watts of power to the two un-used speaker signals in my new head unit.
2) I could put power to the amp somehow.... but then there would be two amps in the system? I also heard someone blew a fuse doing it this way.
What is the correct solution for hooking up the rear speakers?
FYI for anyone buying front speakers- I cut the mounting bracket off the old speakers and put them around a pair of 4" speakers. It saves some money on buying brackets.
1)The audi radio used two speaker signals to power all four speakers, I believe, so im concerned that if I bypass the amp I will lose 100 watts of power to the two un-used speaker signals in my new head unit.
2) I could put power to the amp somehow.... but then there would be two amps in the system? I also heard someone blew a fuse doing it this way.
What is the correct solution for hooking up the rear speakers?
FYI for anyone buying front speakers- I cut the mounting bracket off the old speakers and put them around a pair of 4" speakers. It saves some money on buying brackets.
#2
03-08-2011, 07:46 PM
Have a read through this thread from a couple days ago and post up any specific questions. Did you buy a wiring harness or did you cut the OEM connector and hard wire it when you installed your new deck?
https://www.audiforums.com/forum/sho...d.php?t=165558
Doug
https://www.audiforums.com/forum/sho...d.php?t=165558
Doug
Last edited by Cybersombosis; 03-08-2011 at 09:13 PM.
#4
03-08-2011, 08:46 PM
LOL okay, so here's for the hunnerth time...
The factory non-Bose system uses a seperate amplifier for the rear speakers; it is mounted on the side of the driver-side rear speaker. While it does appear from looking at the head unit harness that there are four sets of speaker-level wires headed out, in fact two of them do not do anything because the rear speakers are run by a set of line-level wires which go to the rear amp. So, if you just take the harness adapter and plug in your aftermarket head unit, there will not actually be any signal sent to the rear speakers.
In my car, I had replaced all four speakers rather than just the fronts, and rather than screw around with trying to use the factory wiring (which if memory serves involves a common ground - anyone can feel free to correct me on that, I'm not 100%), what I did was to just run a new set of wires back from my head unit to the rear deck. It was easy enough; just tuck 'em up under the passenger side of the dash, then under the kick panel and then the door sills all the way back to the rear seat (you'll want to remove the rear seat bottom cushion and side bolsters - if you don't know how, there is [or was back in the day] a bunch of DIY's on AudiWorld on how to take apart various parts of the interior). I would suggest running both sets of rear speaker wires down the passenger side, since if you ever add a subwoofer you'll want to run the power line down the driver side since the fuse box is under the driver side of the dash.
Once you've run the lines, should be easy enough to hook them up by bypassing the amp or just install new rear speakers as well - up to you.
Good luck!
BTW; good idea re-using the brackets for the front speakers - I had Jerry-rigged brackets using bits of perforated steel straps and some screws and washers
The factory non-Bose system uses a seperate amplifier for the rear speakers; it is mounted on the side of the driver-side rear speaker. While it does appear from looking at the head unit harness that there are four sets of speaker-level wires headed out, in fact two of them do not do anything because the rear speakers are run by a set of line-level wires which go to the rear amp. So, if you just take the harness adapter and plug in your aftermarket head unit, there will not actually be any signal sent to the rear speakers.
In my car, I had replaced all four speakers rather than just the fronts, and rather than screw around with trying to use the factory wiring (which if memory serves involves a common ground - anyone can feel free to correct me on that, I'm not 100%), what I did was to just run a new set of wires back from my head unit to the rear deck. It was easy enough; just tuck 'em up under the passenger side of the dash, then under the kick panel and then the door sills all the way back to the rear seat (you'll want to remove the rear seat bottom cushion and side bolsters - if you don't know how, there is [or was back in the day] a bunch of DIY's on AudiWorld on how to take apart various parts of the interior). I would suggest running both sets of rear speaker wires down the passenger side, since if you ever add a subwoofer you'll want to run the power line down the driver side since the fuse box is under the driver side of the dash.
Once you've run the lines, should be easy enough to hook them up by bypassing the amp or just install new rear speakers as well - up to you.
Good luck!
BTW; good idea re-using the brackets for the front speakers - I had Jerry-rigged brackets using bits of perforated steel straps and some screws and washers
Last edited by MrFlippant; 03-08-2011 at 08:53 PM.
#5
03-08-2011, 09:14 PM
Hahaha. My apprentice NHolzschuh can help you out now. Seriously though, there's no need to run new wire as the old wire will suffice. If you are using a wiring harness then it's very simple. Your wiring harness "should" come with 2 sets of RCA inputs. Hook up the RCA rear out of your deck to the RCA rear in of your new wiring harness. Make sure to attach the blue remote wire from your new deck to the remote wire on the wiring harness. On the OEM side, this is the white wire. This alone should get you sound assuming your deck is wired correctly. If you snipped your OEM wiring harness then it's a little more complicated. You essentially need to rewire the low level inputs of your amp with a pair of RCA plugs by stripping the ends off and wiring them up to the corresponding wires from your new harness and then plugging them into the output of your new deck. Let me know if you snipped your OEM wiring harness or used an aftermarket one. If aftermarket, which brand? Can you post a picture of it or provide a link. Good luck.
Doug
Doug
Last edited by Cybersombosis; 03-08-2011 at 09:30 PM.
#6
03-08-2011, 09:30 PM
browny lets start with basic information
1) what headunit did you buy
2)did you buy an aftermarket wiring harness? if so wich one?(please link it form the place you bought it if possible)
i just finished this project with a huge thread about this very same problem, cyber was my teacher.
1) what headunit did you buy
2)did you buy an aftermarket wiring harness? if so wich one?(please link it form the place you bought it if possible)
i just finished this project with a huge thread about this very same problem, cyber was my teacher.
#7
03-09-2011, 06:38 PM
So here's the ebay wire harness I bought. http://cgi.ebay.com/ebaymotors/ws/eB...ht_1646wt_1008
Seems easy enough to repower the amp, but is this recommended? I don't mind running the wires either. Head unit is a Sony CDX-GT250MP. I'll put some pics up too.
Seems easy enough to repower the amp, but is this recommended? I don't mind running the wires either. Head unit is a Sony CDX-GT250MP. I'll put some pics up too.
#8
03-09-2011, 07:14 PM
Well its relatively strait forward then, I assumed you matched all the wires on the harness to the coordinating colors?
Plugged it in as well as ran the blue wire (remote on to the all the other remote on wires)?
Now my problems, and idk why, basically consisted of me wiring the rear front speakers first. I found that if you wire everything but the rear speakers, plug in your wire harness and THEN wire the front speakers(I did this with my stereo on, I kno not the best idea but it helped) it made my rear speakers indefinately work.
Plugged it in as well as ran the blue wire (remote on to the all the other remote on wires)?
Now my problems, and idk why, basically consisted of me wiring the rear front speakers first. I found that if you wire everything but the rear speakers, plug in your wire harness and THEN wire the front speakers(I did this with my stereo on, I kno not the best idea but it helped) it made my rear speakers indefinately work.
#9
03-09-2011, 07:25 PM
Sorry I'm on my fone so I can't edit my last post.
What I meant to say is;
Wire everything BUT your front speakers and plug in your rear speakers. THEN wire your front speakers.
What I meant to say is;
Wire everything BUT your front speakers and plug in your rear speakers. THEN wire your front speakers.
#10
03-09-2011, 07:26 PM
Sorry I'm on my fone so I can't edit my last post.
What I meant to say is;
Wire everything BUT your front speakers and plug in your rear speakers. THEN wire your front speakers.
No this SHOULDN'T matter but its what fixed my problem after a week of fiddling.
What I meant to say is;
Wire everything BUT your front speakers and plug in your rear speakers. THEN wire your front speakers.
No this SHOULDN'T matter but its what fixed my problem after a week of fiddling.