The AVAA (Active Velocity Acoustic Absorber) from the Swiss PSI Audio works like an active bass trap and is the solution for room mode problems between 15-120Hz.
“I wish I had had more pages to describe the virtues of the AVAA.
It's amazing the precision, beauty, tightness and control of the bass
in my mastering room, thanks to PSI Audio. “- Bob Katz, Stereophile June 2016
“There’s no doubt that they are considerably more compact and easier to install than any equivalent passive acoustic bass-trap panels.” – Hugh Robjohns, Sound on Sound 2016
“The difference in low-frequency accuracy between having the two AVAAs powered on in my room, versus turned off, is not at all subtle — it's immediate and obvious.” – Andy Hongh, Tape Op July/August 2016