Somewhere along the way, I had stumbled on a reference that Voigt
never regarded his "Voigt Pipe" to be a good design worthy of producing; that they were inherently flawed.
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Of course, Weems came along and folded it while blocking off a bit of the narrow closed end and giving it a CSA >0: the Driver ended up being moved slightly from the halfway point as well.
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Then this dude came along:
Well, what do you know? As you know I'm in the UK. A week ago Friday, I visited our former home, The Old Parsonage, Frindsbury, Kent. The new owners wanted me to fill in details of the original restoration. Even though I was very young, I have clear memories of the project. I often say, I can remember what happened when I was three, better then last week!
Anyhow the new owners had found an old suit case with some old papers, documents and photographs of mine up in the eves. Most of it was junk like old bank statements. But there were photographs, records of my experiments in the Guys Hospital labs, which included smoked drum recordings of frog leg twitches etc. Also there was the instruction manual of my Quad 22 preamp, my Thorens TD 150 turntable., and the instructions and circuits for my Brenell MK 5 tape recorder, which I have in storage and never got round to restoring.
However, concerning this topic, there is a Hi-Fi News, dated March 1959! This contains the theory and constructional details of the Decca Corner speaker, by no less than its renowned designer Ralph West. So these were the plans I used to construct my first stereo pair of speakers.
The similarity to that Almira design are astonishing. Back then of course we knew nothing of Thiel/Small parameters, and would have had no clue you had to match Vas to pipe volume, and Vas, was not even on the radar. Actually we did not know all this concerning pipes until the year 2000.
So actually the Lowther Almira is a blast from 63 years ago. What goes around comes around, as they say!