[rasz]

Werent there audio system calibrators in the nineties doing room calibration in similar manner (microphone on a cable)?

[moftz]

I had an old Bose surround sound system that did the same thing. You'd place the mic in the best seat in the room and it'd tune the phase to center the sound.

[Tostino]

My Sony surround sound box does this too...

[Justin_K]

Yep my Denon did this in 2000