I am building a Karlsonator 8 with fostex fe206en at the moment. I read many articles and threads discussing the benefits and drawbacks of this design and discussing the suitability of certain drivers. But I am still not sure I understand how it works.
Am I correct in my understanding that it is a double bass reflex with a front chamber with an aperture that functions as an acoustical lens that improves off axis listening.
Am I right or wrong....or partially right but are there more acoustical principles at work?
Am I correct in my understanding that it is a double bass reflex with a front chamber with an aperture that functions as an acoustical lens that improves off axis listening.
Am I right or wrong....or partially right but are there more acoustical principles at work?
regarding the original Karlson Ultra-Fidelity series, they are coupled cavity enclosures with roughly a 2:1 rear chamber to front chamber volume ratio.
system tuning was in ~1/2 octave steps K8~95Hz - - K12 ~63Hz - - K15 ~47Hz.
I consider the original Karlson 15 and 12 to be viable alternatives to front-loaded midbass horns, plus they can employ fullrange and coaxial drivers whereas the midbass horn, unless straight, will be limited to less than 3 octaves range. (Fitzmaurice probably breaks that rule with his curved horns)
its been argued Ultra-Fidelity's proportions were determined by popular aspect of its time, as Karlson's 1951 patent, "Acoustic Transducers", illustrates a taller aspect. FWIW - when I compared a W8-1772 Tangband in a skinny K-coupler vs the 1954 K12, with bulk of each being similar, the original enclosure had 2-5dB more output in the 110-220Hz octave.
the variable width slot can broaden the midrange and some treble frequencies. VHF beams with the larger enclosures/apertures go pretty much straight forwards. Some bounced and off axis HF can reach the upper portion of the front chamber and exit from the narrow portion of the aperture. Small K-couplers such as the mini-Karlsonator by xrk971, can enhance horizontal dispersion at 10KHz.
xrk971 has introduced the "XKi" alignment based on a simplified Akabak bandpass model. Some of those alignment have a 3:1 rear chamber to front chamber volume as are seeking extended low frequency performance.
GregB's Karlsonator puts a tapered pipe rear section behind the front chamber and features the driver being offset a bit "down the line" with the beginning of the line a pointy folded stub. This variant has been shown to work well in various sizes. The original Karlsonator size by GregB is for 12 inch models. Its tuning it around 37Hz. Greg's Karlsonator 8 tunes ~42Hz. I think the Karlsonator 6 is tuned around 62Hz or so.
care of the front chamber must be taken to avoid deep dips and peaks - it would be nice if these "scale" and if so, which chamber shape and aspects are helpful and which to avoid.
some drivers sound wonderful in the original Karlson enclosures - some don't.
The slotted pipe waveguide is useful and may be preferred to horn type for some multi-way K-couplers.
Karlson's asymmetric projectors aka "clam" or "klam", had front chamber volume approximately the same as their rear chamber.
Karlson's K12, perhaps around 1956, took on a distributed slit port. Distributed ports were popular with a lot of manufacturers in that period. If driven by sine wave, then port velocities are high, and overtone distortion is high too. That would not be noticed I think with music comprised of a lot of transient information. A modern builder of K12 could make a removable port panel to try the slits vs a single port.
Karlson enclosures were generally sold without drivers, but examples of K12 loaded with Tannoy Red have been seen.
In 1965, Karlson introduced his down-scaled "X15" model, loaded with CTS 15" woofer. At first it had a mini-klam tweeter driven by a 3" fullrange speaker, but soon employed a slotted metal tube driven by a University Sound compression driver. The "X" way is a very good way to go and would work with a K12.
Karlson made a "K18" as evidenced in one of his brochures.
system tuning was in ~1/2 octave steps K8~95Hz - - K12 ~63Hz - - K15 ~47Hz.
I consider the original Karlson 15 and 12 to be viable alternatives to front-loaded midbass horns, plus they can employ fullrange and coaxial drivers whereas the midbass horn, unless straight, will be limited to less than 3 octaves range. (Fitzmaurice probably breaks that rule with his curved horns)
its been argued Ultra-Fidelity's proportions were determined by popular aspect of its time, as Karlson's 1951 patent, "Acoustic Transducers", illustrates a taller aspect. FWIW - when I compared a W8-1772 Tangband in a skinny K-coupler vs the 1954 K12, with bulk of each being similar, the original enclosure had 2-5dB more output in the 110-220Hz octave.
the variable width slot can broaden the midrange and some treble frequencies. VHF beams with the larger enclosures/apertures go pretty much straight forwards. Some bounced and off axis HF can reach the upper portion of the front chamber and exit from the narrow portion of the aperture. Small K-couplers such as the mini-Karlsonator by xrk971, can enhance horizontal dispersion at 10KHz.
xrk971 has introduced the "XKi" alignment based on a simplified Akabak bandpass model. Some of those alignment have a 3:1 rear chamber to front chamber volume as are seeking extended low frequency performance.
GregB's Karlsonator puts a tapered pipe rear section behind the front chamber and features the driver being offset a bit "down the line" with the beginning of the line a pointy folded stub. This variant has been shown to work well in various sizes. The original Karlsonator size by GregB is for 12 inch models. Its tuning it around 37Hz. Greg's Karlsonator 8 tunes ~42Hz. I think the Karlsonator 6 is tuned around 62Hz or so.
care of the front chamber must be taken to avoid deep dips and peaks - it would be nice if these "scale" and if so, which chamber shape and aspects are helpful and which to avoid.
some drivers sound wonderful in the original Karlson enclosures - some don't.
The slotted pipe waveguide is useful and may be preferred to horn type for some multi-way K-couplers.
Karlson's asymmetric projectors aka "clam" or "klam", had front chamber volume approximately the same as their rear chamber.
Karlson's K12, perhaps around 1956, took on a distributed slit port. Distributed ports were popular with a lot of manufacturers in that period. If driven by sine wave, then port velocities are high, and overtone distortion is high too. That would not be noticed I think with music comprised of a lot of transient information. A modern builder of K12 could make a removable port panel to try the slits vs a single port.
Karlson enclosures were generally sold without drivers, but examples of K12 loaded with Tannoy Red have been seen.
In 1965, Karlson introduced his down-scaled "X15" model, loaded with CTS 15" woofer. At first it had a mini-klam tweeter driven by a 3" fullrange speaker, but soon employed a slotted metal tube driven by a University Sound compression driver. The "X" way is a very good way to go and would work with a K12.
Karlson made a "K18" as evidenced in one of his brochures.
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Original Karlson is a 6th to 8th order bandpass with an acoustic lens output coupler. Karlosnator is a tapered quarter wave tube transmission line with an acoustic lens output coupler. The latter is very forgiving to driver TS parameters. Nonetheless needs to be simulated for best results.
You should check out these threads for more:
http://www.diyaudio.com/forums/full-range/237948-speaker-kicks-butt-large-spaces.html
http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
http://www.diyaudio.com/forums/full-range/239386-karlsonator.html
http://www.diyaudio.com/forums/full-range/268524-xki-xs-ab-initio-karlson-6th-order-bandpass.html
You should check out these threads for more:
http://www.diyaudio.com/forums/full-range/237948-speaker-kicks-butt-large-spaces.html
http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
http://www.diyaudio.com/forums/full-range/239386-karlsonator.html
http://www.diyaudio.com/forums/full-range/268524-xki-xs-ab-initio-karlson-6th-order-bandpass.html
Thanks for the homework! When I have some time I will do some reading on the transmission line principle.
I am almost ready to close the speaker. What worries me is that the "curtains" block access to the driver so I cannot go back and adjust stuffing through the driver hole. If I test with the side panel not glued on I will have air leaks. Or should I clamp on the side with a foam strip for testing?
Another question I have is about the thickness of the acoustic lens. I used 3/4 play but I see original karlsons with 1/2 inch. Would it be beneficial to make a 3 layer sandwich where the panel is 3x 1/4inch but closer to the curve it goes to 2x 1/4 and 2cm before the curve there is only one layer of 1/4 inch? Or does the thickness have no effect on the working of the acoustic lens?
I am almost ready to close the speaker. What worries me is that the "curtains" block access to the driver so I cannot go back and adjust stuffing through the driver hole. If I test with the side panel not glued on I will have air leaks. Or should I clamp on the side with a foam strip for testing?
Another question I have is about the thickness of the acoustic lens. I used 3/4 play but I see original karlsons with 1/2 inch. Would it be beneficial to make a 3 layer sandwich where the panel is 3x 1/4inch but closer to the curve it goes to 2x 1/4 and 2cm before the curve there is only one layer of 1/4 inch? Or does the thickness have no effect on the working of the acoustic lens?
3/4" material is good - 1/2" worked for K8 but it was only 17.5"x11.75"x9"
K-builder Carl N. once made a high aspect K8 about the size of the Karlsonator8 from Baltic birch plywood and even with good bracing, it wasn't strong enough.
I think the most critical stuffing will be in the pointy "stub", fluffed polyfil will probably be fine. If that were omitted, there would be some unpleasant coloration.
here's GregB's damping scheme of polyfill and carpet felt in the rear chamber of the Karlsonator 12
I'll be interested how the Karlsonator 8, which is tuned to around 42Hz, performs with FE206. What's your amplifier?
K-builder Carl N. once made a high aspect K8 about the size of the Karlsonator8 from Baltic birch plywood and even with good bracing, it wasn't strong enough.
I think the most critical stuffing will be in the pointy "stub", fluffed polyfil will probably be fine. If that were omitted, there would be some unpleasant coloration.
here's GregB's damping scheme of polyfill and carpet felt in the rear chamber of the Karlsonator 12
I'll be interested how the Karlsonator 8, which is tuned to around 42Hz, performs with FE206. What's your amplifier?
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FE206EN is one of my favorite Karlson drivers - I've had it mounted in a 0.62 scale K15, "SK8", high aspect K8, K12 and Karlson's K8 (shown below)
K8 (first sold I think in late 1955) were tuned over a full octave higher than Karlsonator8
This is a 1960's Karlson Eight -- - a pair of K's this size or so augmented with a good little subwoofer
would be a lot of fun. FE206EN in Karlson's K12 has a lot of power.
K8 (first sold I think in late 1955) were tuned over a full octave higher than Karlsonator8
This is a 1960's Karlson Eight -- - a pair of K's this size or so augmented with a good little subwoofer
would be a lot of fun. FE206EN in Karlson's K12 has a lot of power.
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ah - I forgot about your Denon. Has xrk971 simulated FE206/EN in the Karlsonator8 ? - I'd like to see its simulation vs W8-1772
Hello, I will build a TQWT Karlsonator with a Beyma 8 ag/n.
Does anyone have a speaker plan for an 8 inch driver? Where is the website of Greg B? Or a thread where I can find a building plan?
What is the myth behind the Karlsonator?
I guess it profits from being close to the floor which means +3db for every driver using a room boundary for sound einforcement. This is the most obvious fact for me. Just think about how many loudspeakers are designed to play close to the floor but only stage monitors for musicians?
More so it will play even louder if you put it against a wall which will give a further +3db.
This is in my eyes the true magic of Carlsson loudspeakers from sweden where the drivers face up with low standing boxes playing up against a back wall. The speakers are more efficient than other ones just playing on stands in the room.
The acoustic lens is a technique I only heard of some Richard Allen monitors if I remember properly.
So it is very interesting to use an acoustic lens to broaden the sound of fullrange drivers. I like and use them a lot. And you do not need to put the fullrange drivers facing up or down and make them work against some wooden cone as usually with omnidirectional drivers.
The TQWT is a very efficient way to make the bass sound loud.
Does anyone have a speaker plan for an 8 inch driver? Where is the website of Greg B? Or a thread where I can find a building plan?
What is the myth behind the Karlsonator?
I guess it profits from being close to the floor which means +3db for every driver using a room boundary for sound einforcement. This is the most obvious fact for me. Just think about how many loudspeakers are designed to play close to the floor but only stage monitors for musicians?
More so it will play even louder if you put it against a wall which will give a further +3db.
This is in my eyes the true magic of Carlsson loudspeakers from sweden where the drivers face up with low standing boxes playing up against a back wall. The speakers are more efficient than other ones just playing on stands in the room.
The acoustic lens is a technique I only heard of some Richard Allen monitors if I remember properly.
So it is very interesting to use an acoustic lens to broaden the sound of fullrange drivers. I like and use them a lot. And you do not need to put the fullrange drivers facing up or down and make them work against some wooden cone as usually with omnidirectional drivers.
The TQWT is a very efficient way to make the bass sound loud.
