I recently installed Windows 7 Pro and noticed a problem when playing media files with a stereo audio source (e.g. mp3's, radio, movies) through my 5.1 surround sound speakers (Logitech X-540). I have an onboard Realtek sound device (ALC883).
The problem I have is this: when I play stereo files, Win7, unlike XP, plays my them in 2.1 (meaning that my rear speakers emit no sound). When I play 5.1 content all plays perfectly well, as I have my system configured correctly through Realtek Audio HD Manager (or Win7 Sound setting). I use the green, pink and blue jacks for input (no SPDIF).
Now, I know there's a function called 'Speaker Fill', which supposedly allows you to distribute stereo sound accros your surround sound system. Unfortunately the speaker fill option fails in making the rear speakers produce adequate sound. The sound produced through the rear speakers comes out distorted and incomplete. I realize that this was an attempt at upmixing stereo source to 5.1 by distributing differen frequencies of some sorts to simulate a 5.1 source. And allthough the feature manages to separate voices from background music pretty well, the output from the rear speakers is as I metioned before unacceptable and often not what I want from a stereo source (because if I'm anywhere other than at my desk, say a little closer to the rear speakers, I can't listen to the music properly because the rear speakers play just the background sounds).
What I would like to be able to accomplish is being able to distribute the complete stereo audio content accross all my speakers or at least mirror the stereo to the rear speakers. Basically what speakerfill would do, only without editing and distorting the sound output to the rear and center speakers.
Of course I could manually set all speakers to 'front' but that would force me to reconfigure manually every time I want to listen to true 5.1 content. I tried different programs like Realtek 3D Soundback or SRS HAL, I read about people having a varying degree of succes with installing older drivers. I installed the most recent drivers from Realtek. All of this to no succes. I even tried different plug-ins for programs like winamp. The only thing that I found to sort of be doing what I want is Foobar2000 when setting it to distribute stereo to 4 speakers, but then again failing at playing true 5.1 content properly and ofcourse since it's an audio player it doesn't resolve my problems for video's or streaming content.
I also read that the problem lies within Microsoft's dicision of removing DirectShow from Windows since Vista. I would very much appreciate if someone could help me find a way to configure my system so that it plays stereo sound across all my speakers evenly and plays my 5.1 source files adequately, without having to reconfigure it manually, just the way it was with XP where everything worked as it should. I like Windows 7 alot appart from this one little thing, but I don't want to have to revert to XP over this.
Something I found to be working much better with my Logitech X-540 set is using the 'matrix' button on my control unit, which basically does the same thing as 'speaker fill' only without the distortion only then I completely lose the abillity to play true 5.1 adequately which is weird: I would expect for the button to either mirror the stereo to the back or do a speaker fill like the software option, rather than doing a sort of "absolute" speaker fill with no 5.1 recognition all.
I hope to get a real solution for this problem here, since this a forum of Microsoft.