Of all the rooms I've set up, it's never been 80Hz. Anything above 60 has resulted in bloated bass.

Could be your sub if it has an audible resonance or rolls off too slow. My 20 year-old, $99 Sony was like that until I stuffed it and shellaced the driver. Freakin' good now to 25Hz even in my 4200 cu. ft. room for music.

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