High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ High Efficiency Speaker Asylum ]

---

[ Alert Moderator ]

---

RE: So what is it about the Karlsons? -1955 K8 and 1954 K15 plans

Posted by freddyi (A) on December 24, 2008 at 09:15:43

In Reply to: So what is it about the Karlsons? posted by dogwan on December 23, 2008 at 21:21:39:

hi Dogwan

The original Karlson 15 enclosure, finished by the summer of 1951 (by Wayne Green's recollection) and introduced as a product in 1952 had goals of loading both sides of the cone, improved dispersion and enhanced reverberation. I think it (and they) can sound very good overall and output can be quite a lot without much cone movement.

Loaded with Electrovoice 15TRX was chosen for the 1964 World's Fair exhibits inclduing Disney's Animatronics.

Smaller couplers seemed to be introduced in 1955 and of course for a given midband sensitivity are basically scaled in half octave jumps with regards to low frequency cutoff.

re: "vetted" - at one time it was stated there were ~200,000 in use.

imo theres some foolishness or misunderstanding in audio if such a device as Karlson 15 with good coaxial (or fullrange) can give a better illusion than some boxes which flush mount a driver to their baffle to minimize "diffraction".

Comparison of modulation distortion of a 3.6 cubic foot bass reflex vs Karlson 15 with Beta 15CX (K15 has about a 3.6 cubic foot rear chamber and tuning looks superficially like that of the reflex and around 50hz)

for a given external bulk a reflex might go a a bit "deeper" small signal - the Karlson could have more power handling and less distortion

KARLSON 15 drawing from January 1954 Radio & Television News

Job Ulfman's site has the July 1958 Karlson 12 construction article - as far as I can tell this was the second Karlson 12" enclosure - theres one mistake in a reference from a rear shelf board. Wings are radial and K15 can be made with radial arc wings.

Job's page with Karlson Articles

Gregg Baker is the administrator of The Karlson Loudspeaker Forum and you may join (by email) HERE

KARLSON EIGHT - EARLY STYLE

I have a very rough condition K8 kit -- there's an extra 1/16" depth insert for external grill cloth making overall depth 9 9/16"

baffle angle appears around 28 degrees from vertical and 3-slit vent port panel canted ~10 degrees forwards from vertical.

sidewalls were grooved to accept the internal panels - this may be from around 1955.

internal width measures 10.75"; external width 11.75".

wings were clipped to clear the baffle.

I'm not sure if the wings were radial but "probably" - will have to try to get good measurements then compare- if not clipped then travel wouild end about 3/4" from the bottom

It has a lively Karlson sound on some organ, guitar, piano, etc. "reverberation" is what gives the illusion of realism in recordings

EARLY KARLSON EIGHT

WINGS DISTANCE FROM SPEAKER EDGE (coming down from the top/"start" of travel"

0= 5- 1/4 (5.25)
1= 5-3/16 (5.1875)
2= 5-1/8 (5.25)
3= 5.0
4= 4-7/8 (4.875)
5= 4-11/16 (4.6875)
6= 4.5
7= 4-1/4 (4.25)
8= 3-15/16 (3.9375)
9= 3-9/16 (3.5625)
10= 3-9/32 (3.28125)
11= 2-7/8 (2.875)
12= 2-3/8 (2.375)
13= 1-15/16 (1.9375)
14= 1-3/8 (1.375)
15= 0.75

wings clip off square at about 15.25" of travel

the vent slits are ~7.875" wide and 0.125" high and occur 2"-3"&4" down from the top front of the port panel.

My K8

An early Karlson K8 kit sheet seen recently on an auction

**************************************************
KARLSON AND KARLSON-RELATED SPEAKER PATENTS

KARLSON PATENTS:

J.E. Karlson US 2586827 “Directive Radiating System” Filed March 31 1945 - a
Parabolic dish microwave antenna with what appeared to be a variable directivity pattern

J.E. Karlson “Acoustic Transducers” US 2816619 filed Dec. 1951, granted 6 years later - deals with broadbanding slot both in loudspeakers and musical instuments.

J.E Karlson “Acoustic System” US 2896736 filed Aug. 1955 - use of a modified Karlson laying on its back using either corner or wall to create a diffused sound image - HiFiLit’s website shows a K12 used in this fashion (laid on back) on the 1955 Karlson brochure page and Bose references this K-patent.

J.E. Karlson “Open End Waveguide Antenna” US 3445852 filed 1968 - essentially analogous with the K-tube waveguide used in Karlson’s X15 2-way speaker ~1966.

J.E. Karlson “Acoustic Transducers” - US 3540544 filed 1968 - concurrent with X15 and described Karlson’s use of ellipse based reflectors to improve the Ultra-Fidlety type via
Fig.6 and Fig 8’s reflctors (Fig6 upper reflector was used in the X15) and introduced the Asymmetric Projector with tapered elipse profile which appeared commercially as the AP-9C ceiling speaker - also- slotted microphones were discussed.

J.E. Karlson “Jet Engine Silencer Nozzle...) US 3543876 filed 1968 - jet engine muffler and rocket nozzles.

LIST OF INVENTIONS 4/24/50

J.E. (Edward) Karlson

1. ELECTRONIC POTENTIOMETER. A variable element which is capable of linear variations of resistances with infinitesimal mechanical motion yet also have capabilities of broad variations in resistance.
2. CAPLESS DISPENSING TUBE. This device permits the use of toothpaste tubes, etc. without the necessity and bother of removing and replacing the cap after each usage.
3. GEOLOGICAL PROSPECTING SYSTEM. A system for use in the prospecting for oil, minerals, etc. This system may also be used for radar applications.
4. RADAR ANTENNA WITH AUTOMATICALLY VARIABLE BEAM PATTERN. This invention provides a simple means of automatically changing the beam pattern of a radar antenna from a pencil beam to a cosecant beam.
5. DIELECTRIC ANTENNA. This invention provides a technique for designing commercial and military antennas which will have overall dimensions than conventional antennae, and yet have equivalent gain and directivity characteristics.
6. BRUSHLESS DC MOTOR
7. ASHTRAY. An extremely simple design for an ash tray which quickly extinguishes cigarettes.
8. PRECISION DELAY CIRCUIT. This circuit provides a delayed pulse at a precise interval following an initial pulse.
9. CHATTERLESS CONTACTS FOR RELAYS
10. TELEVISION ANTENNA. This invention provides a simple, low cost antenna which can be readily hidden or obscured in the average room and is suitable for both F.M. and television.
11. SLOT ANTENNA. This design provides a slot antenna with broad band matching possibilities.
12. HYBRID WAVEGUIDE JUNCTION. This is a wave guide section which has variable propagation characteristics dependant upon the direction of propagation.
13. R.F. TUNER. a simplified tuner for F.M. and television use.
14. ADVERTISING SIGN. Novel electric sigh with quick change possibilities.
15. LIGHT VALVE FOR TELEVISION PROJECTION AND PICKUP TUBE.
16. ACOUSTIC TRANSDUCER. A novel loudspeaker enclosure with improved matching characteristics and controlled reverberation.
17. FISHING DEVICE
18. TELEPHONE AMPLIFIER WITH SPECIAL ACOUSTIC CHARACTERISTICS

RELATED:

W.O Swinyard US 2020166 filed 1935 “Sound Reproduction Apparatus” - a wedge-shaped 20 degree coupler with “V” deflector having non-parallel walls -
“Proto-Karlson”!

N.C. Fulmer US 2787332 filed 1952 “Loud-Speaker System” - a folded 1/4 wave pipe with last section broadbanded with tapered slot - Fulmer’s patent apparently conflicted
with Karlson’s 1st “Acoustic Transducers” delaying grants on both.

R-J Enclosure:

(1) "The R-J Speaker Enclosure" by William Joseph and Franklin Robbins. Published in Audio Engineering Magazine December 1951.
(2) "Practical Aspects of the R-J Speaker Enclosure" by William Joseph and Franklin Robbins. Published in Audio Engineering Magazine January 1953.

"Acoustic System for Loud-Speaker" US# 2694463; Robbins et al filed April 17, 1952 granted 11/54
(nephew of William) Jeff Joseph's Loudspeakers: http://www.josephaudio.com/

J.J. Baruch US2766839 "Loudspeaker System" Filed March 16th 1953, granted Oct. 16th 1956 - deals with math of distributive resistive vents using round holes
- Marty Poppe built X15 using 42-0.375" holes to damp the system for a particular 15" woofer.

John A. McKenzie US 3590941 filed 1969 “Speaker Enclosure” - a dual mouth K-coupler like stacked “Asymmetric-Projector” having a final deflector at each mouth

Robert W. Reams US 4196790 filed 1978 “Acoustic Transducer having Multiple Frequency Resonance” - novel use of Karlson’s slot to create a broad-banded throat in a PA-application quasi-scoop horn with sealed back chamber.

Rodden, M. Raymond US 4313521 filed Feb. 2 1982 "Speaker Housing"

Sapkowski September 3, 1996 "Exponential multi-ported acoustic enclosure" United States Patent 5,552,569

Weiss et al US 5943431 August 24, 1999 “Loudspeaker With Tapered Slot Coupler And Sound Reproduction System” - basically a wedge-shaped asymmetric projector waveguide for 1” compression driver
*************************************************************

JOHN KARLSON ON RADIO 1964


The Inventor's Voice mp3 - John Karlson on radio March 1964
« on: December 25, 2007, 11:29:14 AM »

With Roger Russel's permission here are a few excerpts I took from cassettes (please excuse my poor editing and be careful of playback as the mp3 levels were not normalized and some will be loud relative to others)

Workbench WNCN-FM 3/7/64
Speakers 100min

Eric Towline-moderator
John Karlson (KRC Electronics)
Reuben Guss (Argos-X Electronics)

Intro
clip

John Karlson speaks of the importance of efficiency
clip

3 Dollar speaker transformed by the invention
clip

John Karlson recollects the 8Hz "earthquake" story
clip

Explanation of Karlson coupler
clip

Inventor and speaker manufacturer Ruben Guss speaks

clip

Karlson prices in 1964
clip

Matching of Karlson cabinets to various speakers clip

Karlson output vs excursion clip

Edits: 12/24/08

This post is made possible by the generous support of people like you and our sponsors:

Schiit Audio

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---