ac3 vs ac3 digital on Logitech z5500

I have the WD HDTV Live video connected via HDMI, and to a Logitech z5500 system  via optical.  When the audio source from a video is identified as AC3 [digital],  I hear all the background sounds but no dialog.  If the [digital] tag isn’t on the file, the dialog plays fine.  Since some files don’t seem to have the non-[digital] sound files, I’m toast there.

I never noticed this problem until after the 1.01.17 firmware upgrade, but that may just have been chance.  Anyone else with the problem, any suggestions?

Do you have the same problem if you play it with stereo, rather than optical? 

No, stereo seems fine.  It’s only when I try to use surround sound…  An only when the surround sound says  (digital).  It’s messed up on a dolby digital as well.  All the background sound, but no dialog.  That’s not entirely true, it’s in there, but extremely low volume and muddled.

All my mkv’s played ok via my amp, sent my amp away for firmware upgrade.

Now playing via hdmi direct to tv, ac3 plays ok, all ac3 digital gives motorboating.

I assume the tv cannot process the signal.

The difference between AC3 and AC3(digital) is not a tag, and both are digital ofc, otherwise they wouldn’t be in a digital file to begin with. The only difference is the number of channels in the track, the codec is exactly the same. When you see AC3 it’s just a stereo track (2.0), while AC3(digital) is for a 5.1 track: tbh it would be nice if WD would change it to AC3 (2.0) for stereo and AC3 (5.1) or AC3 (5.1 EX) for surround mixes, it would clear things up a bit.

If the dialogs sound muddied it’s because in a surround track the only channel that contains the dialog in a inteligible form is the center channel ©. The front channels (L/R) only have the reverberations on the walls etc… of the dialogs to give more ambience, so if you are only hearing this it means that you are only listening to the (L/R) channels of the 5.1 mix.

The problem could be that the decoder in your speakers set is applying some postprocessing mode when it shouldn’t.

Check if there is any sound coming out of the center speaker (not just static), if there is some sound, even if it is a bit low and distorted, it could well be that the speakers are forcing an upmix mode or something. It should also clearly say something like 5.1 or 3/2.1 when you play those AC3(digital) compared to the track that say AC3, that should display as 2.0 (or stereo) on that little display. Again, make sure the speakers are not set as prologic, matrix, upmix or anything of the sort when you play a 5.1 track.

In order to troubleshoot both ends it would be nice if you could plug in the WDTV in an A/V receiver or plug a different audio source with optical output in the Z5500, if any of them are set wrong it would show with other devices as well.

I am having the exact same problem.

WD Tv live conected to tv  via HDMI  also have optical connection from wd to Denon receiver and optical from from tv to reveiver.

The sound from the TV  is fine (regardless if I send digital or stereo from the WD).

If I send stereo to Receiver the sound is fine  - shows up as stereo.

If I send digital to the Receiver then the center channel is very very low (almost none) but the other channels are

fine. If however  I change my receiver’s mode to play streo the voice is fine (but of course streo). - ie my receiver is converting the ac3 to streo fine.

My receiver plays other digtital audio fine (ie center channel is fine) if it from a dvd player or from the the TV.