Out, Out, damn sound!
December 11, 2009 4:17 PM   Subscribe

Why can't I get Digital Out (5.1) from my PC to work with my Sony receiver?

I have an Alienware Aurora 5500 "shuttle" PC I inherited from the previous owner, and am attempting to hook it up to my Sony STR-DA4300DS receiver. The receiver works fine for other sources, like a PS3, Apple TV, and HD TV from our Verizon FiOS box. When we attempt to connect the Alienware (running WinXP), we get sound only from the R & L speakers, and nothing from the Center, or the rear two speakers, even when we configure everything for 5.1 sound. (The sound tests indicate it should be playing to those speakers, by the silence they produce matching the visual cues on the screen, and we can hear them when the visual cue is for the R&L speakers.)

At first, we tried a TOSlink fiber cable to connect the on-board system to the receiver, with the above results. We then tried a Digital Coaxial cable, also from the on-board sound card, with the same results. I then dropped in a spare Sound Blaster Audigy 2 ZS, and used the Digital Out on it (3.5mm to Coaxial), but am STILL getting the same results, even with the new sound card.

The receiver is indicating it is only picking up 2 channels. If we force the player (VLC, in this case) to use 5.1 or direct SPDIF / Digital throughput, the receiver then shows 5.1 speakers, and stutters horribly as if it cannot decode the audio (This receiver has all the fixin's, including THX, Dolby, DTS, True HD, etc.).

I'm not sure at this point if it's the PC (OS?), or the Receiver, that is the issue - any advice, or something simple I'm missing? Googling hasn't been able to turn up the results I am looking for.
posted by GJSchaller to Technology (11 answers total)
Set up SPDIF passthrough to yes, and tell the speaker setup in windows to two speakers.
posted by gjc at 4:38 PM on December 11, 2009

No Dice - SPDIF passthrough still produces the stuttering. Setting VLC to 5.1 gives only 2 speakers on the display on the receiver.

FWIW, WinXP is fully updated (SP3), and all drivers are the latest (Creative and Realtek). The fact that we're having a hard time getting the receiver to acknowledge anything other than 2 speakers on the display is interesting...
posted by GJSchaller at 5:12 PM on December 11, 2009

As a control, do you have another device (other than the Sony) you can plug into this arrangement into? That might more conclusively point to the source of the problem.
posted by Blazecock Pileon at 5:54 PM on December 11, 2009

Not offhand, but the thought had crossed my mind - I'll have to check if a friend has a laptop with SPDIF out of some sort.
posted by GJSchaller at 7:13 PM on December 11, 2009

You say the audio stutters, but is it the right audio from all the right speakers? I would blame VLC in that case. I love VLC, but it is kinda horseshit.

Try Media Player Classic, possibly with ac3decoder.
posted by gjc at 7:36 PM on December 11, 2009

Surely you don't want ac3decoder because you're using pass-through and having the receiver doing the decode? But yeah, set pass-through and try some different software.
posted by polyglot at 7:48 PM on December 11, 2009

Or just use the analog outs (if you have them)? DACs on a good card from 2006 shouldn't be horrible.
posted by Monday, stony Monday at 11:53 PM on December 11, 2009

You should be using S/PDIF passthrough output for VLC. Personally, I've had trouble getting VLC's S/PDIF output to work properly in the past (same issue you have). As a test, try using Media Player Classic (with S/PDIF output enabled).

Be aware that you can't transmit "live" surround sound (like games) directly over a S/PDIF connection -- it's only meant for stereo or compressed surround sound. Some higher-end sound cards (and current-generation game consoles) can encode surround to Dolby Digital or DTS in realtime, but it's unlikely yours does, which is why the speaker tests, etc. in Windows aren't working. You should have your speakers set to stereo in that case.
posted by neckro23 at 4:36 AM on December 12, 2009

The source has to be surround so you can only test it with say a dvd and dvd playing software that outputs 5.1

Playing mp3s really wont output 5.1
posted by majortom1981 at 5:48 AM on December 12, 2009

We've been testing off a DVD with 5.1, and also an H264 MKV file that is in 5.1 as well. I'll try Media Player Classic, if it can support the file types.

The media PC is meant mostly for viewing files (as opposed to gaming), but the warning is noted, thank you.

We're also looking at finding a way to connect the internal SPDIF to the HDMI on the video card, allowing it to use the HDMI cable for ease of use, although in light of the above, that may not work.
posted by GJSchaller at 8:15 AM on December 12, 2009

The reason I said ac3filter is that it has a fairly reliable (once you get it figured out) spdif passthrough. I have had trouble getting some players' audio processing to pass it through unmolested. But switching to ac3filter as the audio stream processor, and then turning off all the processing did work for me.

Two other things: for spdif to work properly, you usually have to set [something, somewhere] to allow the media player to have exclusive access to the sound stream. The Windows mixer can mess with passing spdif audio.

And there is something else with checking to make sure it is passing the stream in the correct format. I think it needs to be raw pcm, but don't quote me.

Also check the sound driver and make sure the driver software is set to spdif passthrough as well as the playback software. And make sure the windows speaker setup is still at stereo. And turn off any processing the sound driver might be trying to do (echo, noise reduction, dynamic compression and whatnot).
posted by gjc at 9:55 AM on December 12, 2009

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