I hadn't seen his thread but that's close to my plan. It's not really hard to make a door and it's hundreds of times cheaper than buying a sound proof door. My intent is to make it not look like a door, I'll explain more later.
I have the same receiver, the 4520, if you look on the back there's rca connections for he heights and wides. So I just have the red and white Rca cable going to my other receivers "cd" input, or anyone you want. Then pick two speaker terminals to connect to your heights, like the left and right on the receiver. It's not different that hooking up any input, just happens to be to add extra speakers to your theater.
The old receiver isn't anywhere near as powerful so I ended up keeping it at like 75 percent max volume when I did my speaker levels. At first it was at 50 and I had to set he level to plus 10 decibels so just for Ocd purposes I turned up the volume then the receiver adjustment was much less.
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