I recently purchased a QSC KW152 powered loudspeaker for use with the T3. This 1,000 watt 15" with horn powered unit is nothing short of amazing in all catagories. Not cheap either. I’ve been considering getting another one for a slave. However, I’m concerned that adding another unit won’t add that much more in overall sound. Even the sales rep who sold it to me and works on commision said that I really don’t need it. And, the tech rep from QSC said that many of their customers only use one speaker for their applications as well.
Having said that, I would like to know if anyone here is using this system for theirs and how they are running it.
I’m not using the QSC speakers but I read a lot of good comments on them. The KW wood cabinets are far better suited for bass.
FWIW, doubling the amplifier power to a set of speakers yields a 3dB increase in SPL. Doubling the speakers at the same power yields a 6dB increase in SPL. In the case of the T3, you feel your pant legs rustle by doubling the speakers 
It also minimizes speaker burnout because each is doing 1/2 the work at the same amplifier power.
I know this from experience with my PA - each side has two subs with 18" speakers because I got tired of blowing speakers when I had only one set on each side.
Sold. I’m picking up the second one today.
Thanks.