How does one get 4 channel (LF, RF, LR, RR) sound ?

elmerfud · 10-23-2009, 12:05 PM

What device does everyone use to get 4 channels of sound like a car has ie left front, right front, left rear and right rear from a computer ?

I know that some devices have Dolby 6.1 and 7.1 sound outputs. Can they be made to operate as a 4 channel system ?

Thanks

soundman98 · 10-23-2009, 03:44 PM

this might get overwhelming quick--

computer audio can support 4,4.1,5.1,6.1,7.1, but all are surround effects--meaning that if the original source audio doesn't have any surround effects programmed, the other channels are not going to be used. in a 4 channel computer setup, the rear speakers will only work when the source tells the computer to send a signal to them.

car audio systems with 4 speakers send the same signal to the front and the rear speakers-- left front, and left rear will always be playing the exact same thing-- as will the right front and right rear.

to my knowledge, there is no onboard computer audio driver that automatically will take a 2 channel source, like music and make it play on 4 speakers.

but, there are programs that you can add to the computer to make audio play on 4 speakers, or you can go the easier route, and use a Y-Adapter to split the signal to the front and back speakers.

bratnetwork · 10-23-2009, 04:31 PM

On my Intel DG45FC i use it in 4.1 mode and it plays on all four speakers plus subs without any 3rd party software... it just worked. With the newer drivers i installed it created a virtual effect in the sound and the rear speaker volume lessened so i had to turn the gain up a little more on the rear channel to make it even...

Does anyone know if the Sound Blaster Live! 24-Bit External can do this or if music will only play on the front channel?

elmerfud · 10-23-2009, 07:38 PM

The problem with the Y adapter is that you can't adjust the front/rear balance, otherwise known as Fade.

It makes sense that soundcards should be able to do a simulated sound field with 4.1 because how else would they replay a non 4.1 source, ie a stereo CD for example.

I love the idea of using 4.1 because one can route all the bass to a sub. Makes the selection of the other speakers much less critical, ie they are just mids, they don't need to handle bass.

I wasn't even going to put a sub in my truck before you explained this. Thanks.

popi79 · 10-23-2009, 08:23 PM

The audigy and xfi family sound cards have a cmss mode that will reproduce a surround effect from a stereo signal.
I have this enabled in my system and found it to work pretty good, now remember that sound quality is a very subjective issue; what it sounds good to me might not sound good to you and viceversa.

In that same page let me add that a dedicated sound processor in most cases will render better results than a on board

audio solution.

read more:

http://www.tomshardware.com/reviews/...x,1101-14.html

elmerfud · 10-23-2009, 08:27 PM

Let me complicate this a bit more by saying that I am doing to use a laptop that only has a simple stereo output and thus I will probably be relying on USB sound devices. What are my options now ?

Maheriano · 10-23-2009, 09:49 PM

Most motherboards have 3 audio jacks on them.
1. Line out (stereo playback)
2. Line in (stereo input)
3. microphone input (can also be LFE)

The drivers for the motherboard should allow you to go into the options and retask the line in jack to be a second line out jack. This gives you 2 stereo outputs so you have 4 channels. Then the microphone input can also be retasked as a stereo output for center channel (now making 5 channel output) and also LFE (subwoofer). So right there you have 5.1 sound out of a motherboard which normally only has stereo output.

But it doesn't matter because all songs are recorded in 2 channel so it'll only downmix your 4 channel to 2 channel when playing music anyway.

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