I use the Deeflexx in my amp workshop! I can work at my bench on a customers amp, while he play it (and I tweak it in realtime on the running amp) and have the same sweet spot sound experience as my customer, even if stand on a complete different spot in the room! Actually it not just kills the beam, it makes the sweet spot hearable in the whole room around the speaker! This is just by far the best product made to use with guitar amplifiers, since there were guitar amplifiers around! Never ever doing stuff without a Deeflexx! I was introduced to it from a friend and instantly bought one afterwards!
Works also great with the Matrix Q12a and the AF2!!!
Get your hands on one, listen for yourself.....
Cheers
Paco