I understand Hantra used to own some of the PZC products.
Actually, I used to have 15 of these in my room. Aside from anything you may, or may not know about Mr. Green, my belief is that these devices do more harm to the music than good.
When I moved, I put all 15 up in my new room, and just went from there. Several weeks later, someone suggested that I remove them all, and then add them one at a time. I did just that, and I realized just how much these things hurt the sound.
When I put in the 4 in the corner, they actually made a pleasant difference, which is what I expected. The next one I put in the room, no matter where I put it, actually took away much more than it brought to the room. So, I went with the 4 corner controllers, and sold the rest.
Then I ordered 4 of 8th Nerves controllers for the corners. I replaced the PZC's with these, and there was an amazing difference.
I think the PZC's horn load the corners. They are very destructive too. They have too much absorption. You can take a good room, and make it dead as a doornail with PZC's.
The 8th Nerve stuff covers the entire corner, and is actually preventing most of that horn loading that occurred with the Green devices. I have since added some more 8th Nerve controllers, and find them much less destructive to the sound.
I have a feeling that PZC's would work much better with a different design, but I have no interest in redesigning them myself b/c I haven't the time. If you can find some dirt cheap, you may want to try them, but make sure you also try the 8th Nerve stuff. I like it much better, and it's less destructive to the sound.
L8r,
B