Bill
My unit is a little older than yours but apparently has a different mount. Not near mine right now, but as I remember mine appear to be partially recessed into the cailing, on an angle, on a round mounting plate. My guess would be about 1/3 recessed. They must have changed, or possibly use different speakers in the Bighorn. I would like to upgrade mine to a better system, but the 6 inch or so round mounting plate will definitely present a problem. I have replaced the subwoofer with a much better one and it is behind the recliners, made a BIG difference. If the five surround speakers are built anything like the subwoofer, and they sound like they are, they need to go too. Exactly how are yours mounted? Most speakers are designed to be wall mounted, so finding one that can be ceiling mounted will take some searching, and luck. I have some JBL speakers in my home that mount on a 15 degree V hook that appears could be rigged for a ceiling mount. It would be necessary to drill and tap for a set screw on both the wall side of the hook and speaker side (both sides on these can turn). JB Weld works great too, tends to be permanent though! I could mount these on the wall of the MR, almost touching the ceiling, and could conceal the wires that way, but the big mounting holes are my problem.