I'm pulling my hair out! I have a traditional 5.1 speaker setup. Rear surround sound speakers only. The Audyssy setup fails due to not detecting mid surround speakers. I have tried various manual overides and still coming up short.
Note that regardless of where you place the surround speakers, in a 5.1 setup they are known as "side" surrounds and ideally placed to the "sides" of the couch/seat with the rears in a 7.1 actually going behind the couch/seat.