Originally Posted by Alex F.
Instead of going into the Yamaha's menu, which can be annoying if done often, you could use the back-channel preamp outputs and connect them to an inexpensive power amp, integrated amp, or receiver (or one sitting in a closet, if available). If I correctly understand the Yamaha's 5.1 and 7.1 modes, then you need only power on and off the outboard unit as needed and keep the Yamaha permanently on 7.1 for music. Much less costly than buying another top-end AVR.
Edit: It occurred to me that you could use simply an outboard speaker switchbox to turn on/off the back channels.
That would be a very simple solution if it wasn't for the upmixing. To quote Yamaha's technical support; ""the receiver is generating it's own audio signal from the source that it thinks should be routed to those (back) speakers." In other words, turning off the audio to back speakers while playing a 5.1 audio source will not provide all the audio signals to the surrounds. I've heard it myself...while playing 5.1 content, there are sounds that are matrixed (for a lack of a better term) that takes some signals from the surrounds and directs them to the rears. One time I heard an electric guitar playing in the back speakers while other sounds were coming from the surrounds...and again that was with 5.1 content.
It's like if and when (very rarely) when I take a stereo (two channel source) and select one of the surround modes. In that case, certain audio signals such as the vocals usually gets directed to the center channel.
The technical support team at Yamaha does have their own work around which would be easier. Here's what they suggest...
"One work around that would be a bit easier is to use the Scene button.
You'll first want to create a Setting pattern that has the Surr Back speakers set to none. Once you have that saved you'll go ahead and select your input and dsp you want then do the following.
1. Press the On Screen button
2. Arrow down and hit enter on scene
3. Hit enter on Load
4. Then arrow down and make sure Speaker Setup is checked, you can check the other settings at your own discretion
5. Press the return button
6. Hit enter on Save
Now whenever you want to recall those settings you just press the Scene button you saved them under."
Of course I could do all that, but it just seems easier to me to go into the menu and select "x2 small back speakers" when I know I'm listening to 7.1 audio sources...and then turn it back off for the rest of my audio listening.
Thankfully, the receiver does not up-mix regular stereo signals to 5.1 or 7.1 just because I happen to have a 7.1 speaker setup.