WCC10 for future reference. The Pre-out/in is rarely seen on systems today, but it has a use few people understand. 1)The receiver may be used as a power amplifier should you desire a new audiophile preamp. 2) The pre-out allows you to disconnect from your amp and use the receiver as a preamplifier should you need say 250watts/channel, and there are many quality power amps out there. I hope this explains this setup better.
I read constantly the stereo buyers want to know why the sub-out is not controlled by the receiver with cutoff settings. Please understand that was created for AV-surround world. When you have $2000 speakers with multiple woofers, you don't want to loose that. This allows you to set you subwoofer to fill in the bottom end of your speakers (and few can output below 40 Hz. When you play music you hear the richness of the sound without realizing there is a sub sitting somewhere in the room. All of the sound seems to emit from the main speakers. I hope this helps to understand why Yamaha and numerous others use this output for the subwoofer.
I read constantly the stereo buyers want to know why the sub-out is not controlled by the receiver with cutoff settings. Please understand that was created for AV-surround world. When you have $2000 speakers with multiple woofers, you don't want to loose that. This allows you to set you subwoofer to fill in the bottom end of your speakers (and few can output below 40 Hz. When you play music you hear the richness of the sound without realizing there is a sub sitting somewhere in the room. All of the sound seems to emit from the main speakers. I hope this helps to understand why Yamaha and numerous others use this output for the subwoofer.