Options for wiring speakers??: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

June 21, 2008 9:58 p.m. Hocrest New Reader

I just installed a newer head unit (cheap, nothing special) into an older Subie. The subie is wired with common terminals for the front and rear speakers.

When I installed the HU, I just spliced the front (-)'s and rear (-)'s. At first it worked fine, but after a few hours it sounds like I blew out the speakers?? I really haven't checked it out much tonight yet...

Options for doing this right? 1 - Run new wires, I know this is the right way to do it, but I really don't feel like doing this. I'm not looking for real high quality, just a decent sound. 2 - In another old Subie I had, it looked like a stereo shop did the install. They used the old central ground wires but had it wired odd, If I recall correctly, there were two unused channels from the HU, but all four speakers worked in the car. 3 - Are there any cheap converters to use an 8 wire HU with a central ground speaker wiring?

Thanks for the help...
June 22, 2008 2:09 a.m. fiat22turbo SuperDork

So the HU you bought doesn't have a separate ground for each speaker? Weird...
June 22, 2008 8:46 a.m. Hocrest New Reader

Yeah, the HU has 8 wires for the speakers. The car is wired with combined (-) for the front and combined (-) for the rear.
June 22, 2008 11:06 a.m. porksboy HalfDork

Try fiddling with the balance and fader controls. I seem to remember a similar problem in a car once and that was the problem. When you wire with a common ground like I think you have then you loose the fader or balance depending on what you did. Of course I could be completely wrong.
June 22, 2008 1:28 p.m. Hocrest New Reader

When I first hooked it up, the fader and balance worked fine.

Maybe it's just a coincidence and the speakers just all died??
June 22, 2008 5:04 p.m. Opus New Reader

You may have cooked the head unit. When I had a car wired like that, I took a few minutes and ran wires to each speaker. Took a while, but made it so the head unit did not implode.

If you bought a really cheap radio that had a common ground, then you would be OK though.
June 23, 2008 8:41 a.m. scooterfrog New Reader

Opus wrote: You may have cooked the head unit. When I had a car wired like that, I took a few minutes and ran wires to each speaker. Took a while, but made it so the head unit did not implode.

If you bought a really cheap radio that had a common ground, then you would be OK though.

ooh oooh oooh car stereo something I know. opus got it right. unless its a really cheap headunit and is rated for like 6 watts per channel it has boththe positive and the negative sides of each speaker driven. (like a larger amp that is bridged)

there are a few options. 1) best run new wires. 2) run the postive wires to the speakers and see waht happnes when you ground the common speaker wires thte car or case of the radio. ( tape off the negative wires form teh hes unit. do not ground them. this is effectivyl like running the amp 'single ended' the amp

I would try the second, its easy and can be doen only be removing the head unit.

based upon what you discribe it possible that the car had an (factory) amp. if so you may have over driven it from the head units speaker level outputs. that migght be the problem. if you can find it you can jump around it or answer 2 is the correct answer if the amp is not damaged