1950s Redux...

As anyone who knows me knows that I kind of like messing around with audio equipment, particularly loudspeakers. To be frank,  though, I haven't been particularly active in this department - as in so many others - of late, and I feel the need to try something a bit left-field, just for the sake of it. Pictured are some randomly-chosen documents referring to a particularly oddball speaker design; the Karlson. Dreamt up in the 1950s by the eponymous Mr. Karlson, it was a development of several acoustic ideas in tandem. The overall concept was based on the folded pipe idea, usually exemplified by the - in my opinion excellent - quarter-wavelength transmission line; but with a couple of twists, involving a bit of bass reflex loading with - even - an acoustic resistance unit [although not in all instances of the design], thrown in for good measure.

In fact, the design seems to have had many possible variants; but all share one main characteristic: the curious exponentially-curved waveguide in the front panel, and the angled speaker baffle behind it. Karlson's theory was that terminating the 'pipe' that formed the enclosure with such a waveguide, would suppress all of the odd harmonics that result from the resonance of a pipe-like structure, leaving the fundamental resonance to itself. To be honest, I heard a pair of speakers at an Olympia trade show many years ago that were essentially based around the same principle. On the surface they just shouldn't have worked, but they did: eight-foot tall tubes, with I guess 15" bass drivers within, and the tell-tale cut-out at one end of the tube to do the Karlson thing. Whatever the design theory, these things produced proper, deep, bass; so I guess that the idea has legs after all.

Also, Acoustic used to produce bass guitar cabinets to this design, famously employed by none other than Stanley Clarke in the 1970s; which can't be a bad endorsement in and of itself. I've a mind to give one a try - and mono to boot - and I've got a plan for producing audio quality sheet building material from a triple laminate of thin ply and cheap loft-board quality chipboard. Keep you posted...