Loudspeakers

GoldenEar's use of square ABRs raises an obvious question: why isn't this standard practice? And, while we're at it, why aren't square diaphragms used for drive units too? The square ABR has no downsides that I can think of unless the corners make design of the roll surround more difficult. Its advantage is obvious: a square diaphragm has 11.5% greater area than a circular one whose diameter equals one side of the square, which increases the volume of air displaced for a given diaphragm excursion. But, arguably, this marginal improvement isn't worth the effort. There have been, and still are, square drive units but they are rare and sometimes work on different principles to the conventional moving-coil driver, like Tectonic's square BMRs and the multi-motor bass units of the classic Sony Esprit speakers. All that I can recall have had flat diaphragms. B&W's classic woven Kevlar units were an intriguing hybrid: circular in form but with cone flexure more like a square diaphragm because of the different bending wave velocities in different directions. KH