I was trying to read the original WD TV post, but it is an incredible 173 pages long, and i-m just at page 25.

Anyway, i have my WD TV connected to a Philips LCD by HDMI.

Problem is that the 6ch-ac3 would not play sound, only 2ch-ac3s.

Here is info on some files that NO play (6ch), and YES play (2ch) sound over my TV.

UPDATE: my SOUND was setup to DIGITAL, not to STEREO.

***** NO ***** 0

Overall bit rate : 3 707 Kbps
Writing application : mkvmerge v2.2.0 ('Turn It On Again') built on Mar 4 2008 12:58:26
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 42mn 28s
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz
Language : English

***** YES ***** 1

Overall bit rate : 4 395 Kbps
Writing application : mkvmerge v2.4.0 ('Fumbling Towards Ecstasy') built on Oct 11 2008 20:13:15
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 41mn 50s
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Channel positions : L R
Sampling rate : 48.0 KHz

***** NO ***** 2

Overall bit rate : 3 844 Kbps
Writing application : mkvmerge v2.4.1 ('Use Me') built on Dec 5 2008 18:30:05
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 40mn 41s
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz

***** NO ***** 3

Overall bit rate : 3 746 Kbps
Writing application : mkvmerge v2.3.0 ('Freak U') built on Oct 7 2008 20:39:59
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Audio
ID : 1
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 41mn 45s
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz

***** YES ***** 6

Overall bit rate : 4 496 Kbps
Writing application : mkvmerge v2.4.2 ('Oh My God') built on Jan 18 2009 17:30:28
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 41mn 55s
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Channel positions : L R
Sampling rate : 48.0 KHz

Any ideas why? According to posts, it should play 6ch AC3s just fine.

If i mkextract/downmix to 2 ch/remux, it plays fine.

I would say, that your Phillips LCD just don't decode 6ch AC3 stream. Have you tried the "Stereo" selection for "Audio output" in WDTV Settings and/or using analog signal for audio instead of HDMI?

You need a audio receiver.