Greetings,

Perhaps this belongs in the install section, as there has been discussion related to noise there, but here goes anyway.

I have just completed an install on my '99 Subaru Outback Sport. The installers and I came up with: Rockford Fosgate 6-1/2" mid/tweeters for front speakers, JL Audio 4" co-axials for rear speakers, JL Audio 8" Mini-Subwoofer in back. All powered by a PPI 50Wx4 amp, with two channels driving the front and rear speakers, and two channels bridged for the mini-sub.

This all works pretty well, but I have two problems: 1) Alternator Whine, which has been amply (pun intended) discussed in the install section, and which I am having the installers look at tomorrow morning, and 2) Background noise.

Does anybody else hear this noise? It's a 'static' kind of noise which occurs whether the empeg is on or off, being more pronounced when on. I have attempted to reproduce this static noise in three situations:

1) In the Subie: It's noticeable with the music at low volume, when there isn't much engine noise or road noise, and especially with 'quiet' music such as classical piano. When I'm cranking XTC, it's not much of an issue, but it's otherwise pretty annoying. The noise seems to attenuate with the volume levels.

2) Hooked up to my Cambridge Sound Works subwoofer/satellite PC speakers via 1/8" stereo jack. The situation is much the same as in the Subaru. Quiet music, you hear it, rock'n'roll, no big deal. Again, noise seems to attenuate with the volume controls.

3) My home stereo system: I can barely hear this noise when the empeg is plugged into my home stereo receiver (a trusty old Rotel). In the Rotel case, I have to pause the music and turn the volume on the Rotel way up in order to hear the noise. For all practical purposes the noise with the Rotel is nonexistent. I don't know if this is correct usage, but it's as though the signal to noise ratio is very high in the Rotel situation.

Can anyone shed light on what might help in the Subaru case? I think the amplifier is a good one - correct me if I'm wrong car stereo experts. Will the steps taken to deal with the alternator whine perhaps handle my noise issue as well?

I'm terribly under-educated when it comes to all this, so I will be appreciative of any edification thrown my way : )

Greg Durrett

Serial 00098 - Queue #1108
6G Blue

I have an 99 Subaru Imprezza and also get alternator whine.
After the thrid visit back to the fitter they came to the
conclusion that the problem is with the alternator itself.

If you actually listen to the alternator you can hear it.
And if you remove the connector to that alternator that
recharges the battery(?) the whine goes.

I've still got to talk to my Subaru dealer about the possibility of getting this replaced under warranty.

Then again it may only be a line the fitter made up to get me rid of me! I'd be intrested if this may be Subaru releated.

As to the background noise I do get this to, certainly in the car, but only when the engine is running - when the engine is off and the empeg is running purely from battery its pretty quiet. But then again the gain on my amp is currently (no pun either!) turned right down to reduce the whine!

Regards

Paul

The quad in-car outputs are much better quality than the stereo home outputs, as they have a differential pre-amp stage. Therefore if you are experiencing more "background" noise in the car than at home I would suspect that it is an artifact of the installation - be it cabling, amplifiers, supression, etc.

Rob

Paul,

What amp(s) did you end up with?

I'd seriously question the assertion that it's entirely down to the alternator. The Imprezza's certainly not a problem car in terms of interference - Japanese cars in general tend to be pretty well supressed and very rarely give us any problems. As for disconnecting the alternator plug to see if the noise goes away, all I can say is, don't do it! The chances of blowing the rectifier diodes in the alternator are quite good, to say the very least......

I've done another Empeg install again this afternoon, on a Rover 620, and initially had some noise on the system. In the end, I managed to cut it down to the point where it was no longer an issue. To give you some ideas, what I did in the end was:-

Move the Empeg's power filter a good 12" away from *all* the Empegs other cabling.
Run a very heavy earth cable from the Empeg ground connector down to the amp earth.
Install a 1uf cap onto the alternator output.

That cut the noise to the point where you had to have the headlights on full beam, the heated rear screen on, the Empeg on full volume, and playback paused to even hear a trace of noise. Moving the Empeg RCA ground leads from the main amp earth to another point in the vehicle then cut the noise further, and disconnecting them entirely completely eliminated it. Having spoken to Hugo on a good few occasions about these, I decided not to leave them disconnected, and instead gave the customer an easy means by which to remove them at leisure if he wished.

The Subaru, if anything, should be even less prone to noise than the Rover, although thanks to Honda's influence, they're pretty similar cars electrically. Personally, I'd go back and give the fitter a hard time (we love it really ;-) Yes, the alternator might be the source of the problem, but it's *their* job to find a way around it.

If you don't have any joy, and can't get the noise to a point where you can live with it, let me know, and I'll see if I can come up with a solution.
Dominic

Cambridge Car Audio
http://www.cambscaraudio.co.uk

All,

An update to my initial post about noise.

I took the Subaru back to the installer and had them listen to the noise and whine. They kept it for the day, and when I picked it up in the evening, the noise was....

GONE!!!

What did they do? The guy who originally worked on it hadn't properly grounded the thing! The manager noticed that the empeg-supplied ground leads were left - unused - in the glove box after our first go-round. Sheesh. So they put a set of ground leads on and voila, no more noise.

So the problem hasn't necessarily to do with the Imprez(z)a per se. Whew!

Good luck Paul, and thanks to Cambscar for his frequent help on this board.

Greg Durrett



Serial 00098 - Queue #1108
6G Blue