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It was an odd looking speaker cabinet that attracted a big following
in the golden age of Hi-Fi. It had some issues to be sure, but, it
certainly was loud and proud!

"Theory
The Karlson may be called a broadband-resonator; the resonator in the
design is an aircolumn (in an on one side closed pipe). These pipes
however have a nasty habit. They not only resonate on a frequency with
a wavelength four times the length of the column, but also on the odd
harmonics of this frequency. the characteristics are sketched in fig 1-
a.
fig 1 a,b,c. Halfopen pipe resonance


At frequencies of which the colmumnlength equals half the wavelength
or a multitude of that, the reflection at the open end of the pipe is
in anti-fase, causing an acoustic shortcircuit, resulting in an almost
nihil radiation.
If we now make a cut at the open end of the pipe, then the effect of
this is that the pipe doesn't have a distinct length anymore, causing
the peeks at odd harmonics to widen. (fig 1b)
If we make the cut stretch up to 2/3 of the pipe, and make the cut
exponential in width, the broadband of fig. 1c is the result.


Maybe it's hard to find a pipe with an exponential cut in the
construction, also because John Karlson added in the bass-reflex
principle to increase the radiation at lower frequencies even more.
The Karlson can
therefore be seen as a special bass-reflex enclosure, of which the
port is loaded with an open pipe that has an exponential cut."

What brought this to my attention was that tonight I was F'ing around
with trying to build a crystal set with enough oomph to drive a
Klipsch midrange horn. If you have a good antenna and ground and live
within twenty miles of a clear channel station at night the right
setup can play quite loud, and even DX stations on a cold clear night
can be heard audibly across a room. No amplification, just antenna, a
variable cap, a coil or two or three and a diode. You need to optimize
the impedance match, for which purpose a toroidal output transformer
works very well. Anyway, I was able to pull in a local AM that was
running a best-of Fart Smell show with Wayne Green on. Green is a
goofy old guy who was a goofy young guy when he promoted, along with
all manner of other ****, the Karlson speaker. Seems people still
build these things.