Soundbar can't play LCPCM 5.1?

[AndrewFM]

Hi there,

After many years my 5.1 unit packed in totally so I upgraded to a Sony soundbar with rear speakers. This means my current set up is a Sony Bravia TV, Sony soundbar and a Sony blu-ray player.

I set it up and tested it yesterday. Dolby Digital/DTS/DTS-MA plays as true 5.1 perfectly but certain 5.1 tracks (like Dark Night of the Scarecrow, and quite a few of the Arrow Video tracks (like Tremors) which are labelled as DTS-MA 5.1 but my unit swears are LPCM) can only come out as stereo, from the front speakers.

I've tried with both Optical cables and with HDMI Arc. No difference is made. I've heard optical cables can only do LPCM stereo, and if I'm reading the booklet correctly (which of course I only did after struggling a lot) the unit itself may only be able to play LPCM as stereo, no matter how many channels the track has.

Is there a way to get around this? My TV and Blu-ray player give the options of audio output as AUTO or PCM, so I can't force it to send or interpret it as DD. Thanks.

TV: SONY BRAVIA KDL 40NX703
SOUNDBAR: SONY HT-S40R
BLU-RAY PLAYER: SONY BDP-S1700