Cardioid Sub Arrays are a great thing yes it takes a few more subs in order to achive the necessary energy required. The idea is to keep the subs out of
phase in order to provide more directionality to your subs and
send the low end where you want it. They key is to have the components delayed a 1/4 wavelength apart when flipped out of
phase 180º. There is a lot of math behind acheiving this massive amount of enegery. The other cool part about this is it can be ulitilized in
power alleys and prevent the low end of the subs when in a L/R setup from
phase cancelation you'll have much more even and
clear low end rather then different types of low end nodes throughout the room. Meyer sound is big on the cardiod sub arrays and have a lot of content explaining the theory behind it. I am learning more and more about it everyday and utilizing it with my VerTec a lot. You need to have a measurement
system of some sort to do this correctly and make sure that there is no
latency between different processors because if your timing is off then you stand to lose a large chunk of your low end. I'm not pro with this and I wish I was but I have been doing a lot of research and testing it out on gigs and it works very well. The big benefit though isn't so much the reduction of
stage noise but more so controlling the directionalty of your low end and lessening the amount of nodes in a room.