As a product that looks like it ought to be positioned in the same market segment as the JBL VRX, I remain dumbfounded by the apparent absence of a QSC â¦ I truly am blown away buy the performance of this speaker. Subwoofer power module for KW181, or KLA181. The QSC KW181 is just an amazing piece of equipment that moves a large volume of air with apparent ease. A lot of people seem to agree the JBL PRX718xlf's and QSC KW181â¦ They were being used at a small outdoor festival with a wide variety of bands with fully miked kit and either electric or upright bass and the KW181's were filling the area with a decent punchy low end thump. I am also blown away by the â¦ This is a subwoofer power module that will fit and work with the KW181, KLA181A, or if you just want to make your passive subwoofer into Active this is it! I notice that the recently-announced QSC KLA181 subwoofer still has pitiful low-frequency extension.