Sound from Onkyo SR607 not correct

[ThunderSpook]

Please help, I'm struggling here.

I have the following setup

LG OLED55B7v connected to Onkyo TX-SR607 via optical cable. Optical cable is connected to optical input 2 (CD).

TV is set to audio out via HDMI/Optical.

Amp is connected to a Bose Acoustimass 10 speaker system which is all wired correctly (surrounds to surround, not rear surround etc).

I am using the Plex app on the TV to play movies and the media says it is AC3-5.1

In theory (according to the manual and all the Internet pages) I should have the amp set to either Direct or Pure Audio, but if I do this then I get no sound from the rear (surround) speakers or the centre speaker.

I have gone into the setup on the amp and confirmed that all speakers are outputting correctly.

I've also just loaded up a blu-ray into my Xbox One which is connected to the TV via HDMI, and I get the same.

Help please

[GravelBen]

'Pure Audio' setting on my NR609 (and old SR304 IIRC) is stereo only, I don't think it even uses the sub. The idea is that it turns off most of the processing gubbins for the least interference with the amp circuits.

Not sure about Direct mode, maybe check the SR607 manual?

[ThunderSpook]

I love how spending over an hour trying to fix something garners no results, until you get to the point where you finally put up a forum post, and then 5 minutes later you find the answer

So apparently on the LG TV’s if you have the digital sound output set to PCM instead of Auto then it downmixes the sounds to 2 channels.

Pure Audio should provide the purest sound output from the original source, including 5.1

All working now

[GravelBen]

Glad you got it sorted!

Maybe I've only used pure audio with stereo sources.