The two sb-2000s were causing heart palpitations.

I typically consider rooms up to 800ft^3 small, 800-2500ft^3 medium, 2500-4000 ft^3 large.

My dreamcatchers are in an 800ft^3 room and I have tons of headroom with them even though they bottom out at 1/6th of the power of the M5HPs.

You would buy M22s over M5HPs if you can't afford the extra money. There is no other reason.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated