Up until a few days ago my sytem has performed flawlessly. But now i have no 5.1 suround. I have gone thru the MCE setup.

testing DTS and Dolby Digital via the sound controls in win7 works just fine. I am outputing via SPdif to a sony AVR and only getting 2.1 no matter what i try.

I dont run any filters or special codecs (I have never needed to) for the life of me i can not figure out what happened. I miss my little blue light on my receiver.

Anyone got any ideas? The only thing i have installed latley is the new "Remote Potato" for online scheduling.

Windows update has been turned off.

Edit: This is only happening in Media Center for Live TV and Recorded TV. Media Player sends out 5.1 just fine

 Did you happen to turn on the Volume Leveling option in Media Center under audio?  I had done that and it forces it to come out as 2.1.  The option is in the Media Center settings and then go to video - audio I think and you can select/unselect the volume leveling option.

 Since media center just passes the dolby digital over the SPDIF to your receiver, it has no way to level the volume without decoding it, which media center can't do unless it just uses the non 5.1 audio feed.

 This drove me crazy when I first did it without realizing. it.

Thanks for the reply!

I checked that setting and it is off. What i did see in that screen is the mode that is selected. It is set to night might mode and there is no active way to change it. I don't know what night mode means either.

 Never seen night mode.

 I did have an issue with 7MC with 5.1 audio via SPDIF. It was only on MKVs I had made and a download of FFDSHOW fixed that. As far as inside of MC, it was a simple fix for me:

1. Drop to desktop.

2. Check the settings via taskbard.

3. Reenter 7MC and rerun audio setup.

4. Try it. (it worked for me at that point).

I don't have any problems with MKV's or AVI's in MediaBrowser all DTS and DD tracks work fine there.

I can even play recorded tv with media player and get DD 5.1. I have disabled and enabled settings in the sound manager. switch to hdmi and back to Sp/dif and gone thru the MCE setup to no avail 

What i did just find was that PLAYON installed some virtual 5.1 driver I am now wondering if that has something to do with it. I just unistalled it via device manager. I will test when i get home from work.

I don't recall when this happened and it may have been this way for a while. I rarely touch this rig it just runs

This night mode thing could well be it. It's a form of volume leveling, to prevent explosions or other suddenly loud sounds from rising above the routine sound levels. In other words, it helps keep from waking people up with startlingly loud sounds.

 Frankly I've never found any of these to work well so I never  use them (on the AVR or in software). But if yours is stuck on, I have sadly no idea how to turn it off. Probably someone here can figure it out.

Marc