Speaker Interference

[TimH]

Hello all, first post but I have visited this site regularly both before and after getting my recent car. This site actually helped me in making my decision of what to go for and what extras I should/shouldn’t have, I eventually went for the 2.0TDI S Line (170) in Ice Silver with the 20 spoke rims along with various other extras to suit my needs. From taking delivery at the beginning of Feb I have been more than impressed and have had no problems or issues with the one exception, although the problem is not actually the fault of the car itself.

I had a car kit installed through my company and I was given the option to have the sound come through the BOSE speaker system or have a speaker fitted in the passenger foot well, a no brainer really and went for the first option. Everything was fine and worked as it should with the exception of a whistling sound which seams to come from the front speaker when I accelerate. Turn the stereo off completely and there is no interferance which indicated to me that it was likely the car kit at fault and I got Audi to check this, which they did and as thought confirmed the problem was in relation to the kit installed. If the sound is up loud you can't hear it but with the volume low to medium the noise is there and very irritating.

I have had the Phone engineers back out twice and also had something else fitted at the back of the stereo but there is no difference. They are now telling me that there is nothing they can do about this with the current set up and the only option is to fit the speaker in the passenger foot well, something which I don't really want to do for a number of reasons. I think they are just fobbing me off and I can't really believe that this could not be rectified.

Has anybody else had this same problem with a phone kit retro-fitted with BOSE and if so how was it sorted out? And also I'm sure there are many of you with a car kit fitted with BOSE with no problems but just wanted confirmation of this before I go back and kick off with them.

All comments/advice Welcome, thanks in advance.

 

[Boydie]

Check around your phone kit where the wires are for the bose

RCA leads give out spike signals which can be picked up my speakers for example so try relocating the phone kit or moving the wires

Thats all i can think of so its worth a try

 

[warren_S5]

Whistling through the stereo can be a sign of a bad earth. I fitted an amp in my boot a good many years ago, bolted it down and connected it up. Now I had followed the instructions of earthing it to a decent bolt on the chassis. However I got an awful whining noise when the stereo was on, and it was affected in some part by acceleration as the sound changed slightly. I took it to an audio shop, and they checked it out. They ended up having to re-earth the terminal by scraping some paint (ouch) off the floorpan around the earthing bolt (used a rear seat belt bolt). Screwed it back down and job was a good un.

Actually, that said I had a Sony Ericsson car kit from work and the install guys (I used to work at Vodafone) would not install it as I had external amplification. They said it was too dangerous as it could cause clipping of the speakers as the calls cut in and out. I was running a 5 channel Alpine V12 amp, so NOT the Bose system. Installations of systems are all outsourced these days so its up to the engineer as to whether they go ahead and do it. It must be able to be done as the OE system can come with integrated car kit from factory. Maybe they use inline suppressors to stop any noise.

However you can get intereference from other devices in the car. Is it mounted driver side or passenger side? There must be a fair amount of electrics around the driver side (fuse box / relays etc..) I'd go to a proper audio installations company if your phone company are out of ideas.

Sorry, appreciate this is more waffle than use.

 

[cooni]

yep, whistling noises that correlate with engine RPM is caused by "ground loop interference"... different ground levels causing audio feedback from the alternator... as above, get your car kit grounded better or closer to the amp/headunit's ground point.
that said, i was never able to resolve ground loop interference in my odl car from my ipod when plugged into a car charger (was fine when charger was disconnected)

you can also buy seperate ground loop isolators to hook up to the audio pins on the car kit that are meant to reduce/remove the noise. i haven't tried them before

 

[AndyMac]

You can't link the phone kit to the Bose system. The Bose system is completely amped, and the speakers are 2ohm impedance. The car kit normally links into one of the front speakers, with the mute line cutting the HU signal to the cabin speakers. With the Bose system they would have to link into one of the input feeds to the Bose amp, this will cause alternator whine as most phone kits aren't suitably grounded or electrically insulated. Introducing an aftermarket source into the Bose amp will be prone to electrical interference, amplified by the amp. You need to go for the seperate speaker option.

 

[consilio]

Why not ditch the aftermarket system and retro fit the Audi phone prep?