Adding CarPC to existing audio system. Is true surround sound a viable option?

**mattress** · 05-29-2006, 01:01 AM

Hey guys, I'm looking for advice here. I don't know if it'd be worth-while to add surround sound to the system I already have setup. I haven't added my carPC to the car yet.

Here's a diagram of my current system (before I add the PC)

I know, it's a crappy/rough example. I have 4 RCA cables running from the headunit to the 4 channel amp, and 2 RCA's from the headunit to the subwoofer's amp.

What I'm adding with the actual computer itself, is a 5" sony psone LCD modded to VGA, and using a remote control to control the computer.

The headunit has a stereo AUX-input, and I've already ran the cables to the trunk. Originally I was going to hook the PC up to this, and get stereo from the PC, and control the volume via the headunit ...... but then I got to thinking. if I'm going to have a thousand-watt stereo system with a dvd player, etc... what's the point of the DVD's, if they aren't going to be in surround sound?

So I was beating around the idea in my head, and came up with a couple of solutions:

A) Purchase a cheap 5.1 card (HDA Mystique/Xplosion/Xraider ...)
then, use it's dedicated channel outputs to feed 3.5mm->RCA splitters, so I get channel separation

B) Buy some kind of sound processor that can receive digital input from PC (SPDIF, optical / coax), decode the signal, and output it to the amps.

I guess (A) Would be the most logical solution. Just get a soundcard to do the processing, and output it to the amps with RCA splitters. If I go this route, I will have the 5.1 decoding, but only a 4.1 system in the car. Will this still work? Can I tell the PC to send the center channel to the fronts?

Now comes the tricky part -- Wiring.
I guess I would have to attach RCA splitters to the amps' inputs? and just make sure that only 1 device was outputting at a time? My headunit has 8v outputs, would this effect the PC since they'd be directly connected along with the amp?

Is there some kind of switcher I could get, to just switch between the headunit and the PC?

and I won't be able to control the volume via the headunit volume knob anymore

bummer
Thanks for reading!

**DarquePervert** · 05-29-2006, 08:17 AM

You're correct on how to pull off the 5.1.

Remember that the only thing that will output 5.1 sound are DVDs and some video files. For that reason, 5.1 in the car is pointless to me.
I think the external DAC is the better way to go for true 5.1 surround. You're not the first to want it or attempt it, and you won't be the first to pull it off.
Check out the Show Off Your Project forum and see what others have done.

**mattress** · 05-30-2006, 08:14 PM

I understand that the only things that will be played in true 5.1 are DVD's or AC3 audio, etc, that are digital encoded... I'm not too worried about this, because most sound cards/devices have an option to "upmix" stereo signals, or have an "All channel stereo" setting.

This is the biggest problem I've come across, and can't seem to figure out what to do at this point:

Now comes the tricky part -- Wiring.
I guess I would have to attach RCA splitters to the amps' inputs? and just make sure that only 1 device was outputting at a time? My headunit has 8v outputs, would this effect the PC since they'd be directly connected along with the amp?

Is there some kind of switcher I could get, to just switch between the headunit and the PC?

**jnorion** · 06-02-2006, 09:39 PM

What if you ran an RCA output from the HU into the PC sound card, through your software, and then to the amp? That way you have the option of using either the computer or the HU but it won't do both at once.