I saw this interesting set of speakers on Craigslist, but they sold quickly before I could investigate. They’re the DBX SFX-10s. There’s a very interesting article about their design in the May 1990 issue of The BAS Speaker, the publication of the Boston Audio Society which goes into quite a bit of detail, but the long and short of it is that they’re a pair of speakers designed to provide a fully omnidirectional sound field – and in the paper, there are polar plots to show they did a great job of it.
These are another uncommon design of an active-equalized speaker, similar to the Bose 901, EV Interface, and an early McIntosh line. Has anyone experienced these before? If you own a set, I’d be interested in studying the Soundfield Imaging Controller in my shop; I’d pay shipping to borrow it for a week or two and hook it up to my Audio Precision System One to see what it does.