Audio Setup Issue: 5.1 Sound

JackKieser · April 2012

Ok, so I have a kind of strange situation, and need some help. Here it goes:

I have a set of Logitech 5.1 gaming speakers, which I want all of my audio routed through. All of the devices I want attached to it are:

* PC
* Xbox 360
* Wii
* TV

As of now, I have my PC, Wii, and 360 audio all going to my TV's audio inputs separately (one for each TV channel, since I have separate TV input channels for each device's AV signals), and my TV connected directly to the speakers via RCA connections. Now, my Wii and 360's surround sound work just fine. It's my PC that's giving me trouble.

The problem is that my TV's VGA input only has a single 3.5 mm jack for PC audio, which means that I can't connect my side / sub channels directly to my TV. My question is:

Is there any way to make my PC force all 5.1 channels to go through that single 3.5 mm jack? Is there any way to trick it, or to encode the audio to make it work? Keep in mind: my Logitech speakers are capable of Matrix decoding, if that helps any.

Anyway... I know it's a weird setup. Any suggestions / help?

flammiebc · April 2012

I don't think I've seen a way to force dolby prologic output from my sound card (onboard, in my case), so it might be on a by-driver basis. On the logitech z-680s I use, I just route PC optical out or coax digital out directly to the speaker console. You'd have to take an extra step to switch the speaker input switching to the PC with this method, though you'd have the option for non-matrixed 5.1 by doing so. Which Logitech model do you have?

JackKieser · April 2012

The model of speakers I have are these X-540's. I don't think optical would work because my TV doesn't have an optical-in port, and I know the speakers don't.

I used to route all of the game consoles to the TV, and then route the TV to my PC, and then route the PC to my speakers using standard Green / Black / Orange 3.5mm connections, but whereas my PC had 5.1, my games lost 5.1 (I'm pretty sure), and even then, when I had my TV running through my PC, whenever I'd play something, my PC sounds would also play, which was situationally annoying.

I suppose I could try that setup again, but I'd prefer not to, if I could help it.

baudattitude · April 2012

Your Wii can't output 5.1 channel sound at all, and neither will the 360 if it's hooked up via RCA cables (red & white).

At best, you're getting Dolby Prologic, which is left and right channels with a center and single surround channel. Call it 4.0 audio.

If that is good enough for you on the game systems, then see if your sound card can output Dolby Prologic and hook up the computer using only a single cable.

If you want actual 5.1 audio, you need a receiver with optical or HDMI inputs for the 360 and discrete channel inputs for the PC.

JackKieser · April 2012

Yeah, my 360 is connected to my TV through HDMI. So, are you saying that there's no way to get 5.1 audio from my PC without the 3 3.5mm cables? There's no program or driver that will allow me to encode all 5.1 channels to one output cable or anything (that's not an optical output)?

baudattitude · April 2012

Technically, and I hate myself for mentioning this because it's just going to confuse the issue, TECHNICALLY you can put 5.1 sound over a single wire. Look up "Coaxial AC-3" if you want to know more. Some motherboards even have a coaxial output for this purpose, and if you have an audio card as opposed to onboard audio, it may be able to output it.

However, it's a pretty rare input to see on a TV.

Also, even if your audio output CAN put out a coaxial digital out, the most common use of it is just to pass a bitstream from a DVD. Real-time encoding of the discrete channels of audio that a PC puts out into a 5.1 channel stream is also pretty uncommon.

Post the make and model of your TV and the make of your motherboard or sound card.

mcdermott · April 2012

baudattitude wrote: »

Your Wii can't output 5.1 channel sound at all, and neither will the 360 if it's hooked up via RCA cables (red & white).

At best, you're getting Dolby Prologic, which is left and right channels with a center and single surround channel. Call it 4.0 audio.

If that is good enough for you on the game systems, then see if your sound card can output Dolby Prologic and hook up the computer using only a single cable.

If you want actual 5.1 audio, you need a receiver with optical or HDMI inputs for the 360 and discrete channel inputs for the PC.

DPL2 (which the Wii supports) is 5.0, not 4.0. Just a nitpick, though DPL2 is quite a bit better than old DPL if your equipment supports it.

Also, even if your audio output CAN put out a coaxial digital out, the most common use of it is just to pass a bitstream from a DVD. Real-time encoding of the discrete channels of audio that a PC puts out into a 5.1 channel stream is also pretty uncommon.

On motherboards it's uncommon. On soundcards it's much less uncommon. The bulk of Creative sound cards from the last couple generations can do it, at least those with SPDIF connectors...some just require extra software (available from Creative for a nominal fee).

For movies this is pretty easy...you can use AC3Filter to downmix any 5.1 sources to Dolby Pro Logic (or DPL2 if your speakers support it) in real time. This will cover most media players. For games? I've heard there are ways to route game audio through AC3Filter, but never bothered myself (I just picked up a DDL-capable sound card, since I wanted full Dolby Digital and not Dolby Pro Logic, the money was worth avoiding the hassle...but AC3Filter will do DPL).

So maybe google around to see if this is a feature that has been added to AC3Filter (routing from games), or if there is a workaround that will work for you?

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