I'm not sure about the aims of the designers vis a vis front wall proximity, but the Zus do work well that way. I started with Druids and moved up to Definitions and both worked very well against the wall. My Defs right now are toed in slightly with the nearest rear corner 11.5 inches from the wall behind it. These are sealed cabinets with 4 rear firing subs per speaker. Regardless of how well these may be theorized to work, the net result is literally world class. The Druids have a sort of transmission line which fires downward and is calibrated by adjusting the height above the floor via turning of its spiked feet. Optimized set-up requires comprehension of the design goal and experimentation. Where successfully implemented the Druid will exceed the performance capabilities of almost anything else within its price range. Both of these speakers are badly misunderstood by many forum contributors and mostly overlooked by the mainstream press. They are very worthy of your investigation.
While I am not familiar with Gradient myself, I would take a look at those as well based on the respect I hold for some of the contributors who recommended them. I believe Gradient is a company that made it's reputation designing the only subwoofer that ever successfully integrated with QUAD electrostatics.
While I am not familiar with Gradient myself, I would take a look at those as well based on the respect I hold for some of the contributors who recommended them. I believe Gradient is a company that made it's reputation designing the only subwoofer that ever successfully integrated with QUAD electrostatics.