Marakanetz, I have found that using Argent Room Lens clones between my speakers has eliminated the problem that is normally caused by having the equipment between the speakers. This is very easy and cheap to try. Instructions for them are on the Jon Risch DIY room treatments website. I made 6 of them for about $50. I then followed the Argent recommendations for placement, and found out that they worked very well.
The reason I am mentioning this, is because maybe you can get back to passive this way. And also, look at the Bent Audio website for the new wave in passive controls.
The reason I am mentioning this, is because maybe you can get back to passive this way. And also, look at the Bent Audio website for the new wave in passive controls.