Yamaha RX-V677 silent back speakers

[giantscotsman]

I recently upgraded my stereo amplifier to the Yamaha RX-V677, I am new to setting up home cinema. I have a 7.1 set up. The surround back speakers are about 1ft behind my sofa, 3ft to the side, ceiling height. My surround speakers are at the side of the room, at about 45degrees, 12ft. I have watched two films via my xbox 360 and a few shows on netflix via chromecast, both that claim to have 5.1 surround sound. I hav also watched the below youtube video, which sounds amazing on the front speakers but again no sound at the back.

I used the 'straight' set up on the receiver and relied on the automatic YPAO set up. In both cases the back speakers have made no contribution to the audio. I have repeated the setup and every time the back speakers make a sound, they also work on '7.1 stereo' set up. In options I habe YPAO volume on, Adaptive DRC off, Enhancer on, Cinema DSP 3D Mode auto, Pure direct off.

My questions are:
> Should I have my back speakers in the surround plug, not back surround, if I am watching 5.1?
> Am I using the correct options?
I am very excited to get this set up properly and a bit disappointed at the result so far. Any help is much appreciated.

Youtube video: Transformer FX Helicopter 7.1 (not allowed to post link, sorry)

 

[americanaudiophile]

The back speaker should be connected to the surround backs in a 7.1 set up. Your receiver will indicate on the front display the number of channels that the source you are playing has encoded in it.
The options you mention seem OK but you don't mention what surround mode you are using.
When the source is 5.1 (most are) the receiver should derive 7.1 if you have it in the right surround mode. There are perhaps too many on the Yamaha. You can check the owners manual which will describe what each one does or you can just try them until you are happy.
With the pure surround modes don't expect constant output out of any of the surround channels. The only speaker that will always have output is the center. The fronts are also on a lot. The surrounds will only produce sound when the director wanted them to. Turning them up will increase the volume when there is sound but not when there isn't any.
Other surround modes will make more output more of the time but not be accurate to the film soundtrack.