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General => Car audio => Topic started by: nosaj26 on 02 May 2006, 20:59

Title: engine sounds through speakers
Post by: nosaj26 on 02 May 2006, 20:59
i have just wired up my lovely new 600 wat 4 chanel amp, its currently only powering my rear parcel shelf speakers, and it sounds great, however - as soon as i start the engine you get a high pitched sound through the rear speakers and as you drive down the road it plays back my acceleration and engine sounds through the speakers!!!! it sounds like a high pitched distortion and its driving me mad! any advice on how to cure this or what i have done wrong?. ps the speakers on the back parcel desk are 6 x 9 3 ways if this makes any difference, please help
Title: Re: engine sounds through speakers
Post by: Dizzie on 02 May 2006, 21:04
it's down to a poor earth somewhere. the signal tries to 'go home' using another path if the earth isn't good enough. usually down the RCA cables burning out the earth track on them.

what make is the amp?
Title: Re: engine sounds through speakers
Post by: nosaj26 on 02 May 2006, 21:15
some german make off ebay, i know that sounds dodge but it really did sound the nuts till i started the engine!!!! il check the earthing, many thanx
Title: Re: engine sounds through speakers
Post by: rwalker on 02 May 2006, 21:39
Things to try: Shorten earth cable.  Bare metal contact for the earth.
That should work, if not there are other things you can do... I just cant remember off the top of my head  :wink:

- Ross
Title: Re: engine sounds through speakers
Post by: Dizzie on 02 May 2006, 21:41
could be down to cheap components...

mine did it to a £800 kenwood headunit  :angry:
Title: Re: engine sounds through speakers
Post by: nosaj26 on 02 May 2006, 21:45
did what to it dizzie?
Title: Re: engine sounds through speakers
Post by: GazB on 03 May 2006, 14:07
Or it could be the rca cables running too close to the power lead :undecided:
Title: Re: engine sounds through speakers
Post by: nosaj26 on 03 May 2006, 15:35
cars in garage at mo, il have a go tommorrow see what happens, cheers people
Title: Re: engine sounds through speakers
Post by: nosaj26 on 08 May 2006, 20:36
still no success!!! anybody recomend a good point to earth the amp to, its currently connected under the rear seat, any advice will be good
Title: Re: engine sounds through speakers
Post by: HARDCOR3 on 08 May 2006, 20:39
buy a surpressor from motor spares, stick it in the live, job done...... :wink:
Title: Re: engine sounds through speakers
Post by: Bazzer on 08 May 2006, 21:17
sounds like the alternator might be whining, check the suppressor on the body of the alternator is in good nick.... :smiley:

(and yeah, do everything everyone else says too...
Title: Re: engine sounds through speakers
Post by: nosaj26 on 08 May 2006, 21:20
plenty to try, cheers people
Title: Re: engine sounds through speakers
Post by: nosaj26 on 10 May 2006, 20:36
tried earthing in different places - no joy
tried moving rca cables away from power - no joy
The only thing i havent done is the power and the rca still meet under the dash, is this enough to cause interference?
my next plan is to remove stereo and wire rca's down right of car and power to the left - il try tomorrow, but if anybody has any other ideas please speak up, thanx
Title: Re: engine sounds through speakers
Post by: Bazzer on 11 May 2006, 07:59
Quote from: Bazzer on 08 May 2006, 21:17
sounds like the alternator might be whining, check the suppressor on the body of the alternator is in good nick.... :smiley:
:rolleyes:
Title: Re: engine sounds through speakers
Post by: nosaj26 on 11 May 2006, 10:02
sorry bazzer not ignoring you, il give that a check over tonight, if the alternatoe case is in poor condition what do you advise?
Title: Re: engine sounds through speakers
Post by: Bazzer on 11 May 2006, 10:59
wire brush mate.. you may have to take it off to do a proper job though... And you can get the supressor from Halfrauds too, only a couple quid max...
Title: Re: engine sounds through speakers
Post by: shaggyjh on 11 May 2006, 12:51
I had the same problem and tried all the earthing and wire tricks with no joy.  I admit i didn't try the alternator. 

What i did do is buy a ground loop isolator from Maplin for about £9 and plugged the RCA cables from my stereo into the isolator then into my amp and it stopped all the interference noise. 
It might not help you, but it certainly helped me  :wink:
Title: Re: engine sounds through speakers
Post by: nosaj26 on 13 May 2006, 22:27
bought and fitted ground loop isolator, cost me 8.50 from ebay and works a treat! no interference, job done, many thanks everyone