Payment made for the answer

Matthew230 · 11-03-2004, 08:45 AM

Good afternoon,

I have fitted everything to my car, and it is almost perfect. Though I have noise on the speakers that I can't get rid of.

I have tried everything, grounding the case, motherboard, all to the same point, to different points, internal sound cards, external sound cards.

I get noise when the audio lead is plugged into the PC and the PC has any source of power going through it. It changes when the ignition is switched and with engine pitch. Also get noise that is possibly related to hard drive, and occasionally touch screen noise.

I have the audio lead from the PC tapped into the CD changer audio lines, though I don't think there are any problems here, because if I try another device such as a portable CD player, or the CD changer itself, then it works fine.

So I will make a payapl payment to anyone who comes up with an answer that works, or if you are based near Birmingham in the UK, pay someone to come over and fix it. I am at the end of all other things I can think of trying.

hijinks21 · 11-03-2004, 08:48 AM

tell use what you have in your setup.. HU/amps/inverter etc

Matthew230 · 11-03-2004, 08:59 AM

Quote: Originally Posted by hijinks21

tell use what you have in your setup.. HU/amps/inverter etc

Yes sorry,

Opus 150w, 2.4 celeron, 3.5 hd, 5.25 DVD rom, microAtx Intel board, all in a proper mAtx metal case. I have the option of onboard sound, a creative internal or external sound card. I get the same result with all.

Connected to an indash xenarc touchscreen with only USB device being a GPS mouse.

For audio: I have a CD changer in the back, I have found the audio lines for this and cut them and put on female RCA pugs and then plugged in the PC to there. Like I said, I have tried other devices with that setup and it is fine.

matty_g · 11-03-2004, 09:01 AM

Which external sound card is it? As i had those issues on a similar setup, and went for a audigy 2nx all went away and is perfect.

Matthew230 · 11-03-2004, 09:21 AM

Quote: Originally Posted by matty_g

Which external sound card is it? As i had those issues on a similar setup, and went for a audigy 2nx all went away and is perfect.

This one-

http://www.shentech.com/crusbsoblmpe.html

BiohazrD · 11-03-2004, 09:33 AM

Yeah, I think it is probably because your power wire is running alongside the Y-Cable. That or your soundcard. Try a soundcard with a RCA output.

Dark Angel · 11-03-2004, 09:38 AM

Am no expert on carputers. Yet

But I do know that when I was installing my audiosystem in my bmw, I had to install a ground loop isolator, for cancelling engine noise coming true my amps into my speakers.

Hope this helps.
That'll be 5$

Matthew230 · 11-03-2004, 09:40 AM

Quote: Originally Posted by BiohazrD

Yeah, I think it is probably because your power wire is running alongside the Y-Cable. That or your soundcard. Try a soundcard with a RCA output.

What is a Y cable ?

I have tried a couple of different cards, and the external one has RCA outputs.

Matthew230 · 11-03-2004, 09:42 AM

Quote: Originally Posted by Dark Angel

Am no expert on carputers. Yet

But I do know that when I was installing my audiosystem in my bmw, I had to install a ground loop isolator, for cancelling engine noise coming true my amps into my speakers.

Hope this helps.
That'll be 5$

Tried an isolator, it was rubbish it just isolated everything, including the music.

Matthew230 · 11-03-2004, 01:22 PM

ttt

ApoloV · 11-03-2004, 01:57 PM

Ok well I had HD noise, alt. whine (changin pitch w/ engine RPMs) even noise as I used my touchscreen...

I got rid of most of it by making sure my soundcard (SB Live) was grounded to my HD and motherboard.
I got the rest of it out by using a ground loop isolator like this one
http://www.davidnavone.com/detail.asp?PRODUCT_ID=N-25
or
http://www.radioshack.com/product.as...t%5Fid=270-054

a few things to check out.. make sure your power lines are not crossnig your audio lines, try to have them at least 12" apart. Ideally you want your grounds to be as short as possible.
(Might consider checking your factory ground, some people will replace the stock 4awg ground w/ a 0awg ground, or just supplement with an additional grounding point from your batt. to alt, and batt. to stock ground and cyl head to batt.)

something else to check is if you run a temp power line directly from the Batt to your PC does the sound go away? This could show that your not getting a good enough ground. ?

Those are my thoughts.... Let me know if any of it helps

Apolo

antimatter · 11-03-2004, 02:13 PM

It could be your battery or your alternator.

Explain the noise and how it sounds

dragonBTV · 11-03-2004, 02:59 PM

OK,let everything to the end!

do'nt complain your sound card, they are fine

the noice come from your POWER of PC

sollution:

1.never think about DC to AC converter to normal PC power mode
2.use DC to DC power for PC, there are a few choice on mp3car store
3.do NOT use single ground methord on car wireing, it is for AC FCC control
4.instead trist every pair of your 12V line each pair anythere and ANY inch
5.the length of the wire in each pair should be exzactly same
6.dim of the 12v wire should larger than 0.1mmx10

dragonBTV · 11-03-2004, 03:03 PM

a picture or photo of your installing would show us more information on solving it.

Matthew230 · 11-03-2004, 03:11 PM

Quote: Originally Posted by dragonBTV

OK,let everything to the end!

do'nt complain your sound card, they are fine

the noice come from your POWER of PC

sollution:

1.never think about DC to AC converter to normal PC power mode
2.use DC to DC power for PC, there are a few choice on mp3car store
3.do NOT use single ground methord on car wireing, it is for AC FCC control
4.instead trist every pair of your 12V line each pair anythere and ANY inch
5.the length of the wire in each pair should be exzactly same
6.dim of the 12v wire should larger than 0.1mmx10

Ok - I have an Opus 150w. I have tried using an external power supply, but I get the same result

I don't really understand points 3 to 6

The noise is definitely related to the engine, but I also hear a constant high pitched tone when just the ignition is on, and you can also hear mouse and HDD noise.

How can I test if my gorund is good with a multimeter ??

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