The Dahlquist DQ-10 speakers had been on the market for about 10 years by the time I first heard them. The open dipole sound was totally new to me. I never owned a pair but while I was working as a high school student at Pro Sound in Sudbury I played them all the time. James Taylor through Dahlquist DQ-10s were the pinnacle of musical performance for me at one time.
KEF Electronics, Ltd., was the first loudspeaker company to use computer aided design. The KEF RAM400 had a bextrene cone woofer, rubberized silk tweeter, and the unorthodox B139 oval (racetrack) woofer. Truly one of the finest speakers ever made, its solid, powerful, razor-sharp bass performance has to be heard (and felt) to be believed. Its airy stereo imaging made it disappear into the room. It also was a time-aligned speaker, following the idea first shown by the Dahlquist DQ-10.