Used this design for a mobile disco setup for many years. Fitted with Celestian 200 watt 15" driver -was great and served us well for years. Good deep bass with nice long throw onto dance floors: we setup sound with Sansui SE 9 compu equalizer in various hall and hotel venues and it worked well as a disco PA speaker - fairly efficient. I am homebound now and only do hi-fi. It was a good design and I had it built by a technician from a diy book - eventually sold it to a collector
Christowp
Christowp
I would strongly advice against putting any effort into Karlson enclosures for other than sentimental reasons.
It is well intended design without much founding in science. If I remember correctly, the design even predates the important work of Thiele and Small.
On every occasion I listened to them, they sounded like utter rubbish, fully in line with what might be expected based on insights that only arrived after Karlson did his work on this enclosure.
It is well intended design without much founding in science. If I remember correctly, the design even predates the important work of Thiele and Small.
On every occasion I listened to them, they sounded like utter rubbish, fully in line with what might be expected based on insights that only arrived after Karlson did his work on this enclosure.
Not sure I agree
I believe John Karlson was an Engineer at NASA (who I don't think hire Bozo's...). I don't think the designs are "not founded in science", but perhaps are founded in incorrect execution or are either very critical designs and possibly are being used for more than they are truly capable of. John designed wave guides for microwave transmission as well as exhaust ducting for jet planes. He did hold many patents on some innovative ideas. Whether the audio stuff is or was right or wrong, remains to be proven. I don't have the time, software or knowledge to do it, but I would guess it could be proven or disproved with the right software. Like Tesla, who knows if he based designs on the incorrect physics of the time.
I've heard the Karlson speakers that Oliver Sound made in the 60's (I know Jess), and when used as a vocal projector (only for midrange and high end) they are very good. Quite efficient, excellent projection and clarity.
I also have heard systems with the Transylvania Power Tube company horn drivers (and own a set) that are pretty amazing. Again, bandwidth limited. Excellent dispersion, efficient, and clear.
I think when you delve into the deepest bass regions, these guys have issues. Whether it's the structure or the construction technique or damping, I'm not sure.
I've heard rigs using 4 of these as a bass guitar amp (four of the Acoustic Control Corporation versions), which were pretty poorly made, and they sounded "eh" at best. I good friend said he built some for disco subwoofers and they were very good, but large and difficult to build properly (whatever that means).
Like most horns, the size required can be very large to properly reproduce fundamentals. With today's modern servo designs (the Carver Sunfire woofers are amazing...), it's a question as to whether it's worth the effort anymore...
I believe John Karlson was an Engineer at NASA (who I don't think hire Bozo's...). I don't think the designs are "not founded in science", but perhaps are founded in incorrect execution or are either very critical designs and possibly are being used for more than they are truly capable of. John designed wave guides for microwave transmission as well as exhaust ducting for jet planes. He did hold many patents on some innovative ideas. Whether the audio stuff is or was right or wrong, remains to be proven. I don't have the time, software or knowledge to do it, but I would guess it could be proven or disproved with the right software. Like Tesla, who knows if he based designs on the incorrect physics of the time.
I've heard the Karlson speakers that Oliver Sound made in the 60's (I know Jess), and when used as a vocal projector (only for midrange and high end) they are very good. Quite efficient, excellent projection and clarity.
I also have heard systems with the Transylvania Power Tube company horn drivers (and own a set) that are pretty amazing. Again, bandwidth limited. Excellent dispersion, efficient, and clear.
I think when you delve into the deepest bass regions, these guys have issues. Whether it's the structure or the construction technique or damping, I'm not sure.
I've heard rigs using 4 of these as a bass guitar amp (four of the Acoustic Control Corporation versions), which were pretty poorly made, and they sounded "eh" at best. I good friend said he built some for disco subwoofers and they were very good, but large and difficult to build properly (whatever that means).
Like most horns, the size required can be very large to properly reproduce fundamentals. With today's modern servo designs (the Carver Sunfire woofers are amazing...), it's a question as to whether it's worth the effort anymore...
hm? By Servo you mean like the basstech servodrive (=no conventional voicecoil but a motor)? Is there a sunfire model that uses this motor?
The Carver design (patented) uses a custom driver and passive radiator. I thought it used a server The unit I own has a diaphragm on both sides of the box (which is about one cubic foot small, yet astonishingly heavy), a large foam surround on each side. The driver panel is completely flat and works like a piston. I heard an array used on Broadway for pro sound reinforcement, and the bass impact actually made me hump in my seat ! Not perfect, but very impressive.
Not without controversy either...:
Sunfire Woofer!!
Not without controversy either...:
Sunfire Woofer!!
Transylvania Power Company's "The Tube" slotted waveguide (an adaptation of John Karlson's X15 internal waveguide from the 60's) is probably the best sounding waveguide in its range that I own and that includes DDS Pro90. The Tube can be approximated with a dime's worth of 1" schedule 40 pvc pipe using a Dremel cut wheel and a half ellipse slot. Drivers from B&C, Eminence and Selenium sound fine with this size 1 inch format Karlson waveguide. (BTW, Karlson patented the open end waveguide for microwave application)
Acoustic Control's 115BK and BC2 appeared to be simplified versions of the KHYBOE. 115BK was very well built of good plywood and braced with 3/8" allthread. I have a pair of Ken Kessler's KK Audio KHYBOE type (see LEECH ad at Job Ulfmans Karlson site) and those are excellent with "The Tube" on top.
My Klipschorns sound crude and thuddy in comparison.
Karlson's original K15 (completed in the summer of 1951 making its show debut in 1952) with a good coaxial does a lot of things right including drum transients, realistic vocals, bowed bass and harpsichord.
Trying to discern changes with a single mic point can be futile as there are subjective changes when the aperture slope and widths are altered which the ear hears but will not show with the mic.
Low mass and strong motors are suited for K-couplers. The little 8 inch coupler is unimpressive and can sound bad with certain speakers but does have a sweet spot which is good with certain organ recordings. The original 1954 Karlson Twelve (listed as "Karlsonette") sounds good with the Fostex FE206EN fullrange and imo better more cost effective than my K-horns.
For those with open minds, good new couplers are waiting to be built - imo they should be approached with some thought plus an inexpensive but sufficiently rigid test box with removable parts should be made. Several sets of wings of different flare and starting gap can be investigated.
If distances aren't quite right in the front chamber, then a deep steady state dip can appear. The original K15 coupler used a "shelf" to deflect most of that dip.
After the first K12, Karlson went to distributive vents. These were the days of mix and match according to whim and dollar. When I've tested the slit vents with sine, there's quite a bit of distortion but on music transients such as drum beats the slit vents sound "fast" - perhaps with good acoustic musical instruments (bass viola, drums, etc.), a steady state condition is rarely reached.
Over at Gregg Baker's Karlson Speaker forum there has been some activity with new couplers. I had a somewhat larger 8 inch coupler recently which loaded with FE206EN was more enjoyable than my faux La Scala setup. A friend also has experimented with taller couplers pioneered by Carl Neuser. A recent 28" tall 8 inch coupler has gotten high marks and produces decent graphs. (its possible to have good graphs imo and very poor sound such as a 2031P does)
Karlson was a genius.
Acoustic Control's 115BK and BC2 appeared to be simplified versions of the KHYBOE. 115BK was very well built of good plywood and braced with 3/8" allthread. I have a pair of Ken Kessler's KK Audio KHYBOE type (see LEECH ad at Job Ulfmans Karlson site) and those are excellent with "The Tube" on top.
My Klipschorns sound crude and thuddy in comparison.
Karlson's original K15 (completed in the summer of 1951 making its show debut in 1952) with a good coaxial does a lot of things right including drum transients, realistic vocals, bowed bass and harpsichord.
Trying to discern changes with a single mic point can be futile as there are subjective changes when the aperture slope and widths are altered which the ear hears but will not show with the mic.
Low mass and strong motors are suited for K-couplers. The little 8 inch coupler is unimpressive and can sound bad with certain speakers but does have a sweet spot which is good with certain organ recordings. The original 1954 Karlson Twelve (listed as "Karlsonette") sounds good with the Fostex FE206EN fullrange and imo better more cost effective than my K-horns.
For those with open minds, good new couplers are waiting to be built - imo they should be approached with some thought plus an inexpensive but sufficiently rigid test box with removable parts should be made. Several sets of wings of different flare and starting gap can be investigated.
If distances aren't quite right in the front chamber, then a deep steady state dip can appear. The original K15 coupler used a "shelf" to deflect most of that dip.
After the first K12, Karlson went to distributive vents. These were the days of mix and match according to whim and dollar. When I've tested the slit vents with sine, there's quite a bit of distortion but on music transients such as drum beats the slit vents sound "fast" - perhaps with good acoustic musical instruments (bass viola, drums, etc.), a steady state condition is rarely reached.
Over at Gregg Baker's Karlson Speaker forum there has been some activity with new couplers. I had a somewhat larger 8 inch coupler recently which loaded with FE206EN was more enjoyable than my faux La Scala setup. A friend also has experimented with taller couplers pioneered by Carl Neuser. A recent 28" tall 8 inch coupler has gotten high marks and produces decent graphs. (its possible to have good graphs imo and very poor sound such as a 2031P does)
Karlson was a genius.
It is possible to have very bad graphs and listenable sound, but the Karlson coupler does some very weird stuff to phase and frequency response.
Some folks like weird stuff, the Karlson does lend it's sound to a speaker.
Here are phase and magnitude charts of an 8" Karlson I grew up listening to, my Dad scaled down the July 1958 Popular Mechanics 12" plans (using distributive vents) to build a pair for the basement.
IIRC, the test was done with the cabinet about 6 feet in the air, mic 4 foot from front, on axis.
They did sound better than the (Magnavox?) console stereo upstairs, which used 15" speakers firing sideways and horns firing forward...
Attachments
here's an 8 inch coupler testbox outdoors with its innards arranged in two versions - one has the Karlsonette style horizontal single-slot vent and cupped reflector (green trace) - the other (yellow trace), a t-line path. Driver = FE206EN
An externally hosted image should be here but it was not working when we last tested it.
Looks like "True RTA" does not show the flaws in as much detail as Smaart.
+/- 12 dB instead of +/- 15 dB.
Ouch.
Edit: +6, -7 dB, not near as bad as my old Karlsons.
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5dB/vertical division on that graph so acceptable imo - ask Murphy about TrueRTA - it shows enough warts for my taste (I didn't make the HAK8 graph above and IIRC it was done with pink noise) - here's two slotted tube at TrueRTA's max resolution (1/24 octave) - one 9" with 1.875" ID with an inner piece like the X15 speaker - the other a thinwall 1" pvc tube I made. Both tubes were tilted down 30 degrees from horizontal - driver was the old Eminence CD8
An externally hosted image should be here but it was not working when we last tested it.
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Mis- read the graph, that 8" Karlson is not nearly as wild as mine.
But the 9"x1.875"ID parabolic tube comes pretty close to as wild, a 25 dB range in the octave from 1600 to 3200 ;^).
TrueRTA's max resolution (1/24 octave) does show the warts pretty well !
Art
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here's a recent 8" coupler (called "SK8) which I thought came out good and better than Karlson's 8K - its about 13.5" wide, 20.5" high and 13" deep - that's a 1960's factory 8K to its right. SK8 sounded better to me than my faux La Scala setup (FH1/K55V-511/APT150) - good K-couplers can be made.
An externally hosted image should be here but it was not working when we last tested it.
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Hey Freddi
nice to see you still posting pics here
first time i ever come across a Karlson slot like the one in the enclosure seen on the right hand side in your picture.
Any advantages over the standard-issue-2-pieces-of-wood-that-make-a-slot-configuration.
It strays a little from the actual mathemathecal principal of forming a slot as it is the idea in the Karlson-enclosures. It seems the beginning of this slot starts rather "messily".
Does this have any significant effect on sound or measurements?
Hope it aint a silly question and that is has been discussed in great lengths already.
cheers
Maarten
nice to see you still posting pics here
first time i ever come across a Karlson slot like the one in the enclosure seen on the right hand side in your picture.
Any advantages over the standard-issue-2-pieces-of-wood-that-make-a-slot-configuration.
It strays a little from the actual mathemathecal principal of forming a slot as it is the idea in the Karlson-enclosures. It seems the beginning of this slot starts rather "messily".
Does this have any significant effect on sound or measurements?
Hope it aint a silly question and that is has been discussed in great lengths already.
cheers
Maarten
Alan Weiss holds a patent which might keep some from doing it. K15 was recently offered in France but at high end prices. It takes some experimentation to make new couplers which are outstanding. Cogent's Steve Schell has supported K15 for a long time. So did the late Walt Bender of Audiomart.
We're getting close to this thread being a decade old, let's keep this thing rolling! 
I like my DIY Karlsons; they do some things quite well and have their weak areas, like most other types of speakers. They are the 1954 K12 "Karlsonette", built from ¾" BB plywood. The driver in them are Richard Allan CG10T 10" fullrange. On top is the Transylvania Power Company "The Tube", along with a Selenium D220Ti 1" compression driver, crossed-over 3rd order at 3kHz. The CG10T is rolled-off first order above 3kHz, and has it's own roll-off above ~6kHz.
Here's the in-room, un-EQ'ed response of the above system:
It's a bit too hot between 150Hz and 250Hz, which I EQ down, but that pretty much the only aural offender; I do boost bass at 64Hz and 32Hz, but it does well without it. The Transylvania tube above 3kHz does a remarkable job IMO. I also ran some Philips AD9710 8" fullrange drivers in these Karlsonettes, w/o the Transylvania tubes and they did quite well; certain types of music required no EQ whatsoever.
I also built the experimental 5/8 scale 8K, dubbed K5, in which I tried both Fostex FF125K and Pioneer A11EC80-02F. These don't sound as good but some recent work on them has made things slilghtly better.
These don't make a pretty graph, that's for sure:
I won't go to the extremes of calling JEK a genius or a madman, but he certainly had some interesting ideas. Some of the claims made in advertisement of the Karlson are quite baffling IMO, but I take this speaker for what it is and enjoy it quite a bit.
IG
I like my DIY Karlsons; they do some things quite well and have their weak areas, like most other types of speakers. They are the 1954 K12 "Karlsonette", built from ¾" BB plywood. The driver in them are Richard Allan CG10T 10" fullrange. On top is the Transylvania Power Company "The Tube", along with a Selenium D220Ti 1" compression driver, crossed-over 3rd order at 3kHz. The CG10T is rolled-off first order above 3kHz, and has it's own roll-off above ~6kHz.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here's the in-room, un-EQ'ed response of the above system:
An externally hosted image should be here but it was not working when we last tested it.
It's a bit too hot between 150Hz and 250Hz, which I EQ down, but that pretty much the only aural offender; I do boost bass at 64Hz and 32Hz, but it does well without it. The Transylvania tube above 3kHz does a remarkable job IMO. I also ran some Philips AD9710 8" fullrange drivers in these Karlsonettes, w/o the Transylvania tubes and they did quite well; certain types of music required no EQ whatsoever.
I also built the experimental 5/8 scale 8K, dubbed K5, in which I tried both Fostex FF125K and Pioneer A11EC80-02F. These don't sound as good but some recent work on them has made things slilghtly better.
An externally hosted image should be here but it was not working when we last tested it.
These don't make a pretty graph, that's for sure:
An externally hosted image should be here but it was not working when we last tested it.
I won't go to the extremes of calling JEK a genius or a madman, but he certainly had some interesting ideas. Some of the claims made in advertisement of the Karlson are quite baffling IMO, but I take this speaker for what it is and enjoy it quite a bit.
IG
Hoi Vacuphile.....ook toevallig..nog een ZBA-er
Klaré in the city of Hoorn (Noord-Holland) still delivers ready sawn wooden packages to build 12 or 15 inch Karlson's.
Mainly for the use on stages.
groet,
Maarten
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 - from what I understand Alan Weiss worked with Karlson in the later days
http://www.google.com/patents?id=ph...&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q&f=false
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 - Gregory Raw termed it a Sci-fi-scoop”.
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
http://www.google.com/patents?id=ph...&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q&f=false
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 - Gregory Raw termed it a Sci-fi-scoop”.
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
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