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Karvin again [message #28235] Tue, 24 July 2007 21:14 Go to next message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Back in those dear dead days beyond recall (before stereo), in 1951 or 52, I built a carbon copy of an EV back-loaded corner horn in birch in the basement of our EE bldg. Used an EV SP12B speaker and it was nice. A few years later, 1958?, a friend and I built a pair of Karlson's in our apartment living rooms of 3/4 inch Luan plywood. I can remember running up and down the aisles of the local supermarket searching for cans of the right size to make the interior ducts. I put a nondescript (i.e., cheap) GE 12" speaker in it and stacked my EV on top of it in a corner of the apartment living room. The result was fantastic! A large projected spatial soundsource good enough that I carried them around to demo in other friends digs. My only test record was the King of Instruments disc with the scale on the organ at Symphony Hall Boston on it (Harrison) but it sounded great with my Weathers FM pickup and viscous damped arm, home brew preamp and "Williamson".

Re: Karvin again [message #28236 is a reply to message #28235] Tue, 24 July 2007 21:16 Go to previous messageGo to next message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Whoops! I meant Karlson. Sorry.

Re: Karvin again [message #28239 is a reply to message #28236] Wed, 25 July 2007 14:11 Go to previous messageGo to next message
efaber is currently offline  efaber
Messages: 4
Registered: May 2009
Esquire
freddyi loves those k-cabs. 50's style retro.

Re: Karvin again [message #28243 is a reply to message #28235] Wed, 25 July 2007 21:46 Go to previous messageGo to next message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Got a problem. You can tell from my first message that the Karlson cabs my friend and I built contained ducts. As I recall Comet Cleanser containers w/cardboard sides were a perfect fit. But rummaging through all the Karlson references I can find today, even very old ones, nary a one has any internal ducts. What we built were clearly Karlsons with the big exponential V front and canted speaker mounting board. But, if recollection serves, the interior was divided into two chambers ducted together with the cleanser cans. Can anyone explain what is wrong here?

Re: Karvin again [message #28246 is a reply to message #28243] Thu, 26 July 2007 11:36 Go to previous messageGo to next message
Bill Wassilak is currently offline  Bill Wassilak
Messages: 402
Registered: May 2009
Illuminati (1st Degree)
Nothing wrong, the original Karlsons with the 15's had the ducts, but on the smaller models they had used slits instead of ducts. What you're doing is letting the low frequencies from the rear chamber vent into the front chamber. The exponential V shape on the front acts as a broad band resonator supposedly for the full frequency range and to get the wide dispersion. I was investigating using these for my PA system a few years back, but it seems real tough to get them to do anything below 50HZ (15" model). Freddy Iverson on the Karlson form is the one to talk to. But they were in a class of what's called a broadband resonator.
HTH
Bill W.

Re: Karvin again [message #28251 is a reply to message #28246] Thu, 26 July 2007 21:36 Go to previous message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Thanks, Bill
-Dick

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