What is a B&W 801M?

I believe those are the earlier Matrix series. Could you give more specifics as to the construction/appearance of the speakers?

Barry - these have the bass eq box and seem to have metal dome tweeters. My memory(always suspect) is that the series 80 had the soft dome (brown colored) tweeter?they appear to be bi-amp/bi-wireable (jumpers plus to plus ,minus to minus on the back of the speakers.No level controls on the back of the heads - hmmm - I think that would mean they aren't series 80 (non matrix) 801s?

Do they look similar to these?

http://www.soundsgoodtomehouston.com/bw801/801_pairopen.jpg

These are the early matrix cabinets.

I'm not a B&W historian by any means, but I had a friend back in my college days (mid '80s) who had a set. The "Matrix" moniker referred to the construction of the cabinets as there was an internal "Matrix" of bracing to reduce cabinet resonance.

Barry, those in the photo are NOT matrix cabinets. The first 801 with a matrix cabinet was a ported design.