How much have you spent on putting together your ideal audio playback system? How much have you spent maki g sure that your room isn’t singing along and undermining your dream system? If the answer to the last question is minimal or nothing then time for a rethink. Bass frequencies are incredibly long and in most normal rooms produce a use room modes which undermine your valuable system. This little device does what passive room treatment for bass frequencies can’t. In my small 4.5m x 3.5 m room is was about to sell off all of my HIFi gear befor trying the PSI AVAA. I came across them on the Thomann website and I am very glad that I did. I now have three in my room and the effect is staggering. The overblown and boomy bass has gone, to be replaced by deep , tuneful bass that complements rather than disrupts the rest of the performance. And with the 30 day return guarantee offered by Thomann you can try the AVAA in your own listening room with minimums risk, just make sure you order, for the sake of symmetry, a minimum of two ABAA’s!