This 1.5Mb/s DTS 48/24 4.0 channel sample is not decoded properly by
mplayer, or by dcadec built from the svn r82 of libdca.  The right sound
seems to be there, but the main thing you hear is a buzz, like the sound was
chopped at 1kHz or something.  A good description in words isn't coming to
mind very easily, so just listen to the sample.

 My logitech Z-5500 speakers play back the sample just fine over S/PDIF, and
recognize it as a DTS 48kHz/24bit stream with 3 front and 1 rear channel.

This ~1min sample was cut from the DTS core of the DTS-HD track on the
Edward Scissorhands BluRay.
http://bluray.highdefdigest.com/606/edwardscissorhands.html
Uploaded with (58MB) and without (14MB) 720p x264 video.