I am on the market for a new audio receiver (not a home theater) and I
have a question regarding 6.1 and 7.1 surround formats.

My small condo has 6.1 speaker connections built into the Living Room
walls. I do not want to add another center-back speaker due to cost and
the lack of space in the room. Will a 7.1 receiver "downgrade" to a 6.1
format or will some of the sound be lost on a firm 7.1 broadcastdue to
my having only one center-back speaker?

If some receivers do downgrade by design, is there a particular term
I'm looking for to find this feature?