Question Yamaha RX-V667 optical input question / problem


Novice Member
Hi all, I have a Yamaha RX-V667 receiver and am struggling with the Optical setup. I have a LG OLED65BX6LB TV and feed HDMI input from my various devices to the TV and then feed the audio from the TV via an optical cable to the RX-V667. (I don't used the TV speakers at all and have selected Optical out on the TV).

When I do a test using one of the YouTube 5.1 or 7.1 audio videos (on the TV), the back LH and back RH audio comes out of the front LH and RH speakers with only faint audio coming out of the back speakers.

I have setup the Yamaha for 7.1 with 7 speakers and a sub woofer and when performing the audio test on the Yamaha amp all is working as it should so the amp is working.

I can only assume that I have missed something on the amp setup for optical input using either 5.1 or 7.1. Has anyone else experienced this sort of problem or can anyone suggest what I'm doing wrong.

Thanks in advance for any feedback.


Distinguished Member
YouTRube doesn't carry multichannel audio and anything you access via the YouTube service will be encoded with stereo 2 channel audio. Ignore what those who've upmloarded their videos to YouTube have labelled them with. Those users are unaware that YouTube doesn't carry more than 2 channel audio and that YouTube downmix anything uploaded with more than just 2 channels to 2 channel PCM.

Also note that S/PDIF optical will be limited to no more than just 5.1 channels. Optical cannot convey 7.1 channel audio and will be limited to SD lossy 5.1 formatted audio. Optical cannot carry 7.1 audio or HD formats such as Dolby TrueHD or DTS-HD Master Audio. You'd also be limied to no more than just 2 channels of PCM audio data and you'd be unable to convey Dolby Digital Plus (DD+) via optical.
Last edited:


Novice Member
Thanks for the information. I was not aware that all the 5.1 YouTube audio test sound videos would only be producing 2 channel output. I'll do some more tests using the DVD player with confirmed 5.1 sound tracks.

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