::.. Speaker Ground from/to Headunit

[Qube]

When wiring the headunit, does it technically matter which grounds the speakers are connected to?

Like can reverse the front/rear or 'technically' tie them together eh?

Case in point, the stock radio wiring on my 88 build doesn't have 'independant' rear speaker ground wires. I'm playing around with several headunits (heh), and forgot what I did with them before.

(purple/stripe, green/stripe)


EDIT: Research:

http://home.insightbb.com/~todd.kenyon/stereo.htm


Note that old radio only has a single left and right (+) output (blue and yellow wires) with no speaker (-) wires. Front and rear is split at fader. The system therefore uses a common ground. This means you only have to attach the new radio's (+) speaker wires, leave the (-) speaker outputs unattached. DO NOT twist them together. Simply cap them off, DO NOT ATTACH THE NEGATIVE SPEAKER OUTPUTS TO ANYTHING. That is the "secret" here.

Hmmm... so is that telling me to ground the front speakers but just leave the rears as is? Course that quote applied to the e28 with the console fader control... :|

In a nutshell, I have the rear speaker grounds left over from the aftermartket radio harness...

[pingu]

It might do.

It's likely that on lower power head units, the +ve signal (OK, there are two +ve signals but I'm going to pretend for convenience that things are mono) is connected to the amplifier and the -ve is connected to ground.

On higher power head units, it's quite possible/likely that the +ve signal is connected to an amplifier and that the -ve is connected to another amplifer that provides an "upside down" version of what the +ve amplifier is doing. This might an odd arrangement but it allows you to drive more power into the loudspeakers as, in effect, it doubles the available supply voltage from 12V to 24V. 12V is limited to about 18 watts RMS per speaker.

Do you feel lucky?

[Qube]

Haha. I have no idea what you're talking about. I love that. Lots of info but I'm clueless :)

1. I found some peculiar wiring. Supposedly Blue/Red and Yellow/Red is the + for front speakers... so what's up with this?

2. Also, what's this wonderful blue connector?

3. Now when I 'fade' to rear, I can still hear the front, but barely... and the front crackles when faded all the way back :|

NB: yeah I'm lazy now. I'll switch to spade connectors once I get a harness

.

[Felixdacat]

You can tie all of the speaker grounds together. You will only need to be concerned with your positives.

[Ausmpower]

You can tie all of the speaker grounds together. You will only need to be concerned with your positives.


Only if you want 'fries with that!'

Modern head unit use floating grounds as outlaid by pingu.

Just cap the rear earth leads out of the head unit.

[Qube]

Only if you want 'fries with that!'

Modern head unit use floating grounds as outlaid by pingu.

Just cap the rear earth leads out of the head unit.

Mmmmm... so basically speaker positives only, cap all four grounds from the HU... ok... I'll try that. On that note, I also cap the two grounds coming from the car then.

Any answers for the other questions, perhaps? :) Thanks!

[Ausmpower]

With mine I have the fronts wired with both positive and negative.

The rear I am using only the positive leads with both the HU earths capped seperately.

I'm running a Pioneer DEH-P6850MP HU.
Front stage: Mb Quart mids in the kick pannels factory tweeters (all on factory wiring).
Rear: JBL mids (factory wiring)
Sub: 2 x 12 isobaric's, 400w soundstream mono block.

[Qube]

Hmmmm ok... I wonder if there is a singular answer to this :)

[Ausmpower]

I've got to pull my head unit to add my mp3 stacker next week. I'll write down the colour codes of the wires I've used (what goes where) and post them up here.

[chris_e34]

I definitely wouldn’t recommend tying all grounds together. The static from the fronts when you fade to the back is most likely interference. Separate the grounds and you will get a cleaner sound altogether, and it will eliminate the interference. I would also check the polarity on all of your speakers. Verify the negative and positive leads for each channel are wired to the correct negative and positive on the corresponding speaker. Having a speaker switched i.e. Left rear wired to left front on the head unit. This has given me static when I fade countless times.

[Felixdacat]

Have done this many times in autos and trucks, and have never had any feedback, or distortion when fading to front to rear, or left to right and right to left. If you connect the postitive to the corresponding positive, you will not have any problems. Ie: front left of hu to front left speaker, and so on.