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#1 2013-02-09 03:09:13

karlsonkab
Member
Registered: 2006-03-21

KARLSON COUPLER PLANS

Karlson's K15 which was prototyped in the summer of 1951 by John Karlson and Wayne Green - this classic made its show debut in the fall of 1952

K15 plan from the January 1954 issue of Radio and Television News http://img825.imageshack.us/img825/5469/k15k.png

Drenner "build-in" adaptation of K15 http://img62.imageshack.us/img62/9405/k15plannegwh7.jpg

A 1956 change-over of K15's port width and shelf gaps  http://picasaweb.google.com/gregmuon/ST … 6131883202
Early K15's trim dimensions http://img62.imageshack.us/img62/8397/k … ueltq4.jpg  http://img62.imageshack.us/img62/5218/k … lueit5.jpg

Greg B.  "The Karlsonator"  - a proposed K-coupler for 12 inch speakers  with added low frequency extension http://picasaweb.google.com/gregmuon/ST … 3473417410

Karlson's first 12" driver K-coupler introduced in the fall of 1954 aka "Karlsonette" (the little 8" coupler had not yet appeared) http://picasaweb.google.com/gregmuon/ST … 1071519938

A factory Karlsonette/K12 with BetsyK in front of one of my K-horns.  The little Karlson loaded with FE206EN has more impressive bass than the K-horn.
betsykk12.jpg

Karlson's most famous K12 from around 1956 and published in the July 1958 issue of Popular Mechanics http://picasaweb.google.com/gregmuon/ST … 2036444962

Side sketch of "3rd" K12 which had a full width rear shelf/lowpass-choke http://imageshack.us/f/232/plank12sealedsm1.jpg/

Another cool driver for K12 is Eminence's Beta10CX - it sounds very good with the new circuit value Eminence crossover (lowpass 2mH/10uF - highpass 3.3uF/0.33mH)
- its another K-horn killer - - some of my K12's have higher sensitivity 12" coaxials which may outperform equivalent priced fullrange
krustybeta10cxs.jpg

Karlson's 1968 K8 http://picasaweb.google.com/gregmuon/ST … 3897445682

A slightly larger 8" driver K-coupler developed on the late Gregg Baker's forum  "SK8" http://picasaweb.google.com/gregmuon/ST … 8905766834

SK8 with a fast flare aperture
sk8nirvanasuper8stamped.jpg


Greg B's Fulmer- exit pipe for Betsy-K  http://picasaweb.google.com/gregmuon/ST … 4867082050

Greg B's SK6.5 for FE166EN http://picasaweb.google.com/gregmuon/ST … 5853178818

Greg B's Super - T %$# for 8" drivers - - got a good report from John Lapaire with FE206EN - I'm not sure but it may lack the hit region peak which some 8's will do in K12 http://picasaweb.google.com/gregmuon/ST … 9966245090

John Lapaire's prototypes of Greg B's 6.5" and 8" couplers next to a K15
k8615.jpg

Amadeus Mozart's High Aspect Karlson-coupler for 6.5" Fostex  http://picasaweb.google.com/gregmuon/ST … 2699373874
XK6.5front.jpg

Last edited by karlsonkab (2013-02-13 23:57:49)

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#2 2013-02-09 17:01:57

Greg B
Member
From: Los Angeles, CA
Registered: 2006-03-19

Re: KARLSON COUPLER PLANS

Damn, I sure have my fingers in a lot of that K stuff, for someone with more or less a passing interest. wink

The Betsy-K design is really just a folded TQWT with a Fulmer exit.

Regarding the '58 K12, did someone archive the plans that Gregg Baker had translated? These also show the corrected dimension arrow showing the back shelf height. (the arrow is supposed to end at the inside bottom, not outside bottom)

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#3 2013-02-10 16:13:23

IG
Member
From: Québec, Canada
Registered: 2011-03-17

Re: KARLSON COUPLER PLANS

IIRC, that little red SK6.5 had tractrix wings - looks great!

IG

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#4 2013-02-10 17:16:46

Pit Hinder
Ein Member
From: Germany
Registered: 2006-11-08

Re: KARLSON COUPLER PLANS

Shave me and tar me, call out the army - the rear is a bleeping bass reflex!
When you got that right, does the height of the slot/hole/vent really make a difference?

   Pit

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#5 2013-02-10 20:14:17

karlsonkab
Member
Registered: 2006-03-21

Re: KARLSON COUPLER PLANS

up to 10dB difference in part of the spectrum as slot height was truncated on the skinny K-coupler below.   Futhermore, this aspect had 2-5dB less output in the 110-220Hz octave with a Tangband W8-1772 than the same 1772 mounted in a classic Karlson 12.   These particular K8s sound good with an inexpensive Sammi 8" fullrange topped with a Selenium slot-helper tweeter.    imo -it can be good to have a narrowing slit for high aspect Karlson-type above the regular aspect slot - - that may not show on a graph but can affect the subjective treble "air" and bass damping.

xk8adjustslotheight.jpg

Look at one of Carl Neuser's 8 inch test couplers' aperture - also note the APT50 drive K-tube tweeter
chak81.jpg

Last edited by karlsonkab (2013-02-10 20:20:19)

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#6 2013-02-10 20:26:05

karlsonkab
Member
Registered: 2006-03-21

Re: KARLSON COUPLER PLANS

Marinus red K6.5 has what I call a "bass-clef" front chamber cross-section.  My skinny K above downwardly tapers towards the top.  This must affect the center of the air mass.
--also his K-coupler is vented at the top between the top plate and the top of its curved reflector while mine shown above has a vent directly above its woofer.

bass_clef.png

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#7 2013-02-10 20:49:52

IG
Member
From: Québec, Canada
Registered: 2011-03-17

Re: KARLSON COUPLER PLANS

Yep - does indeed look like a bass clef!

Pit - once you have a reasonable rear chamber, the front attaches as the second part of the type-2 bandpass, the quarter-wave resonance of it usually dominating over any of Helmholz inclination, or so I choose to understand it.

Is this the year where we'll finally see a Lowther in a K12?  big_smile

IG

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#8 2013-02-11 00:25:40

Greg B
Member
From: Los Angeles, CA
Registered: 2006-03-19

Re: KARLSON COUPLER PLANS

The basic idea is that it is like a short TL (or ML-TL), except that it's turned around backwards, so that the 'rear' radiation is the main output. The simple port is replaced with a slot, which has the effect of broadening the resonance, as well as allowing a broader bandwidth to escape.

IOW, yeah, it's a bandpass with a funny port.

I'm bored of K, what other unloved esoteric enclosures are left to futz with?

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#9 2013-02-11 00:58:59

karlsonkab
Member
Registered: 2006-03-21

Re: KARLSON COUPLER PLANS

dunno what's really cool - ?   some speakers may work well with R-J venting  -  I've had planars/electrostats/TL-stat hybrid/front-loaded horns/rear loaded horns/BVR/open baffle - the Karlson's were and are at times the best overall and least boring and biggest bang for the bulk - - for bass - guess the Graham-Holiman cabinet didn't pan out (?)  one thing I'd like is a K15 bulk coupler sans front shelf and with internal K-tube.   ZZZZZZZZZZZZZZZZZZZzzzzzzzzzzzzzzzz

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