Can someone clarify? (AC3 SPDIF question from FAQ), sound too quiet

[homerpez]

I'm referring to this statement from the "Audio FAQ":

Any C-Media 8738 based sound card has given great results whether it’s built-in to the motherboard or a PCI card. These cards are low budget but perfect for an inexpensive SPDIF setup. They also pass both DTS and DD without issue.

I have the problem many people are having with encoded AC3, it sounds too quiet under "typical" conditions (out from speakers) on their sound card.

However, when manually switched to SPDIF-only output (as in PowerDVD or WinDVD), the audio suddenly gets loud on the receiver, as it should be.

Where I'm at myself, I have a Diamond 7.1 channel card, which uses the C-Media 8738+ chipset. The drivers I'm using (homebrew, since there are no "official" drivers for Vista anywhere) Seem to allow for either:

Stereo Output (both analog and SPDIF)

5.1 Output (both analog and SPDIF)

SPDIF Only (only addressable by a DVD program...?)

It's the last two that baffle me. I can set it to "5.1 speakers", and then select "SPDIF Device" as the default. What I get is proper 5.1 Sound, but very very VERY quiet. It easily gets 2-3 times quieter when playing AC3 as it is playing stereo, and it effects everything, even my receiver.

When I play movies in either PowerDVD or WinDVD, the result is the same, unless I manually select "USE SPDIF" in the audio menu. Then, suddenly, my analog speakers shut off, and I get full-volume 5.1 from SPDIF on my reciever (which is what I want).

What I would like to have happen, is for Windows to output correct 5.1 at full volume every time, NOT JUST within a DVD player program! Windows seems to only allow me to select "SPDIF Device" as a default, but it does not translate into the same loud output I get from the DVD progams "USE SPDIF" mode. It's still quiet, and shared with the analog speakers.

Does anyone know a way to accomplish this in Vista and using a C-Media 8738+ based sound card?

If it's any help, I'm using the drivers found HERE (http://cmediadrivers.googlepages.com/home), since I haven't found better ones yet for Vista - official ones do not exist. However, if there are better ones out there, I'm all ears. :)

I can't be alone here... thanks for any and all help... :thanks:

[homerpez]

BAH... "Murphy's Law" strikes again, but this time in a good way.

Of course, I make yet another lengthy post, and 2 seconds later, I find the answer. And in the driver's FAQ yet.

People with similar playback issues may want to take note... AC3 filter seems to fix this problem, if you have it set correctly (your sound card may or may not be similar):

How do I enable DTS/AC3 passthrough in WinDVD / PowerDVD / Media Player Classic / AC3Filter?
WinDVD: Start WinDVD, right-click somewhere in the video window and select 'Setup...'. Then go to the audio tab and select "Digital S/PDIF Out to External Processor".
PowerDVD: Start PowerDVD, right-click somewhere in the video window and select 'Configuration...'. Then go to the audio tab and select the "Use SPDIF" entry from the 'Speaker Environment' box.
Media Player Classic: Open Media Player Classic and open the 'Options' window ('View' -> 'Options' or just press the O key). Select the 'Internal Filters' node from the tree on the left and double click the 'AC3' entry in the 'Transform Filters' list. Choose "SPDIF" in the window and click "OK".
AC3Filter: Click Start, Programs, AC3Filter and then "AC3Filter Config". Check the "Use SPDIF" box.

On the drivers I'm using, it basically makes it so any time ac3 audio is present, it will default to SPDIF only. When it is stereo, it will still be shared. But... it got me the strong SPDIF 5.1 audio in ANY player program, and that's what I wanted.

Hope this helps at least 1 other person out there, then my embarassment will be worth it. :p

[niknik]

It helped.
:)