After taking Bob McCarthy’s SIM 3 / System Design class it is apparent that moving one or two measurement mics around the room (as I have been doing) is an inferior method compared with using more mics and leaving them in place during the measurement / tuning process. Logical but who owns more than one or two measurement mics? I happen to own 10+ Earthworks omni mics. No excuse not to start using more mics!

Bob stated that (5) is a mimimum for combining (2) speakers. These are the (5) positions. I will use my recent measuring opportunity for reference.

Going from one side of the room to the other:
OFF AXIS – A
ON AXIS – A
XOVER – A/B
ON AXIS – B
OFF AXIS – B

Bob calls these mic position classifications:

OFFAX
ONAX
XOVR

There is one more mic position classification Bob calls SYM (for symmetrically opposite element) that I’ll ignore for the moment since this post is about (5) mics.

The ONAX positions are used for EQ decisions. The XOVR position is used for delay decisions and to verify that a proper spatial crossover.