Poor sound with CarPC straight to amps

Locus27 · 07-24-2008, 10:16 AM

Okay guys, here's the layout. I'm running a carputer with a Via Epia M1000, 512 of ram, 300GB hdd, and SB Live! 24bit USB. I've got a lite install of Windows XP with both Media Center and TVedia, as well as winamp, and all the appropriate drivers and codecs installed. Audio out from either the onboard sound or the SB is run via 6' 3.5mm shielded phono cable to a 3.5mm -> RCA splitter. From there it runs into a Kenwood KAC-7204 to power the rears and a Kenwood KAC-6202 for the fronts. Rear speakers are Infinity Reference 9613i 6x9's, fronts are Infinity Kappa 63.9i 6.5" in the doors. Subs (yet to be added) will be Infinity Perfect 12DVQ running on Kenwood 9102d's.

Now that that's out of the way, I seem to be having a great deal of trouble getting good sound out of the carputer. The sound is tinny with no bass, and often distorts. The problem seems limited to the carputer, cause when i run a line from the pre-amp out on the pioneer head unit in my other car, the audio's fine, deep, and strong. So, suggestions on what to look for? Here's some things I've come up with so far:

Just plain crappy audio processing: it sounds bad with both the SB live and the on-board audio, but the SB live sounds fine when it's hooked up to my laptop and an SB 5.1 setup, so it could be an issue with the carputer.

Bad phono cable: i've tried several and not gotten any better sound

ground loop issues: this seems to be a common theme on the forums. I'll have to look at getting some isolators

Ideas, suggestions, comments?

robhur · 07-24-2008, 12:10 PM

As stated before, check for ground loops they cause alot of problems. Then check your sound card, sometimes the little amps on those go out and the card needs replaced. Check your comps sound levels too, you mite have it down or maybe mixed wrong. If all else fails put a pre-amp on the line and see if that makes a difference, the sound card mite not have a weak signal for some reason or another.

scott_fx · 07-24-2008, 12:35 PM

Quote: Originally Posted by robhur

As stated before, check for ground loops they cause alot of problems. Then check your sound card, sometimes the little amps on those go out and the card needs replaced. Check your comps sound levels too, you mite have it down or maybe mixed wrong. If all else fails put a pre-amp on the line and see if that makes a difference, the sound card mite not have a weak signal for some reason or another.

a ground loop wouldn't cause the issues that he's having and he said the soundcard works fine when hooked up to his laptop, so it's not that either. I do agree that it could be a levels or mixing issue.

just to be clear:

alt audio source hooked up to the amps = good
alt computer hooked up to the usb soundcard then to the amps = good
car computer via the usb soundcard to the amps = bad
car computer via onboard sound to the amp = bad

if all of those are true it is most likely software related. i'd check your mixer first

robhur · 07-24-2008, 12:58 PM

I actualy have mine hooked up through an onboard and it sounds amazing. Now that I think about it ur right ground loop wouldn't do that, it would just buzz/ static.

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