Karlson tube HF waveguides - how many have tried them?

[freddi]

although limited on LF k-tubes can sound pretty good imo

Transylvania Power's "The Tube" by Walter Zintz
http://img457.imageshack.us/img457/7622/tt6wb.jpg

thinwall 1" tube
http://home.planet.nl/~ulfman/images/galleria/Fred_Tube1-Thin.jpg

pattern for 1" pvc tube
http://img398.imageshack.us/img398/3497/ktube1aa6tp.jpg

1" diy tube vs an 1.875" ID x 9" long Karlson style tube with a concentric pre-waveguide
http://home.earthlink.net/~buddhaboy2/9v7.jpg

X15 copy tube cloned from ~1966 speaker system
http://home.earthlink.net/~buddhaboy2/X15/X15Tube.jpg

 

[jamikl]

Thanks for those links Freddi, especially the pvc tube one. I have some old 12 inch speakers which I intend to mount in a ripole with a 30 to 34 inch long tube above and an old 8 inch full range firing up this, tube size to suit, with a slot in one side and will try to do a small high tube like in your link tilted down about half way down the slot but inside the first tube, just to see what it all sounds like. There will be a compression chamber behind the mid range as in a horn. Just got to scout aound the plumbers - drainlayers now to if I can find an
offcut of 8 - 9 inch pvc tube for the mid. I do have some old low power 6 inch full rangers as well from some old japanese speakers. Might make finding the pipe easier.
jamikl

 

[freddi]

Hi Jamiki - I put a B&C driver on a Transylvania Tube - sounds pretty good

when you make a half-ellipse tube 1"ID - ~5.3" long is plenty enough and about 1/8" starting gap - it will probalby tilt about 30 degees upwards if the slot is facing down

here's my "TT" - combined with K15 its quite a lot of power on drums in a small room. Zintz's Transylvania tube had a 2 degree downwards sidewall taper.

Freddy

An externally hosted image should be here but it was not working when we last tested it.

some tubes (maybe Ernst Beck's specimen) had a roller pin about 1/2" from the throat - these didn't

An externally hosted image should be here but it was not working when we last tested it.

 

[bikehorn]

i tried one, just for fun made out of a few sheets of A4 paper rolled up and with the slot eyeballed. had a second-order butterworth HP at 2k on a Selenium DH200E...i didn't really like the results i got but i don't think i tried very hard...gave up shortly after. I have some PVC pipe laying around which i may try once i get a replacement diaphragm and some time.

the paper K-tube had great HF extension, but didn't seem like it went down to 2khz...it was about 11 inches in length(the length of an A4 sheet...)

I've always wondered, does a K-tube actually "load" a compression driver or simply act as a waveguide? doesn't a compression driver need some kind of loading to work properly? I know very little about the workings of a compression driver.

 

[freddi]

I think 11" for 1" format might (?) restrict its horizontal dispersion - Zintz had it about right with ~5.3" and 1/8" thick cast aluminum structure. Dave Young made 2" x 11" tubes for 2" drivers and 2-12" for PA use.

a snippet of one of Dave's posts from Ulfman's forum:

"----As to the K-couplers use for high frequency propagation, if offers advantages and disadvantages.

When a horn is coupled to a compression driver, there is a noticable increase in midrange volume.

When a K-coupler is attached to the same driver, the
change is not as dramatic. The horn is easier to install in a cabinet with its flat flanges.

The Transylvania Power Company's Tube requires an added bracket(see Ernst Beck's article) In order to work properly it needs to be tilted back as the main axis of radiation is 35 degrees below 0.

The horizontal dispersion is very broad. And if you do mount a Tube with the flange flat to the baffle, it will be constantly getting hit and compromising packing in a car or truck.

The 2" K-coupler was used on top of a front
loaded 2-12" mid box. When the boxes were used outdoors, there were high frequencies present in the area in front of the stage with the cabinets on eighter side of the stage.

This didn't happen when I used horns. The highs projected well into the field.

The sound quality of the coaxials improved when the horn was replaced with the K-coupler.

However, not every coaxial speaker is designed with a coupler in mind.

Again the horizontal dispersion improved. One was installed into a small monitor and

you could stand 10'away at 80 degrees off axis and still hear highs. "

 

[Rewind]

I have tried it now above 3k Hz and a k tube sound real nice. I just opened it up 2mm extra and it was a huge difference. Sound more open now. Tweeter is Beyma CP 380/M.

I noticed it was gradually opening so I closed it. It gave a stronger tweeter sound with more tweeter punch and volume. But it seems to be some kind of dips in frequency curve when using a Behringer CX3400. I am sure I have to overlap some xo points in a minidsp.

 

[xrk971]

Don't you just love how paper and tape can make a nice sounding speaker?

 

[Rewind]

Don't you just love how paper and tape can make a nice sounding speaker?

Oh, believe me. https://vimeo.com/m/72501089

 

[freddi]

they're normally made with a cross-section the size of the driver exit, and no flare although the commercial Transylvania Power product ("The Tube") had a downwards sidewall taper of 2 degrees (it sounds great)

here's Karlson's antenna patent for the K-tube. Carl has worked on an oval tube and likes laminated wood veneer for K-tube material

https://www.google.com/patents/US34...a=X&ei=v58OUv3UKOTA2AXbt4HIBQ&ved=0CDYQ6AEwAA

I'd like to know which antenna Karlson made which was advertised in the 1950's as adopted by the U.S. Navy

 

[Rewind]

Anybody else thinking of sonotube Karlsson?

 

[POOH]

The Transylvania tube is ok to me but doesn't load the driver like a horn in the midrange or upper midrange. Maybe in a situation where you use it for 6k up and need big dispersion it would be the ticket.

 

[freddi]

I'd say the little K-tube is good from 1K6 or so up. Its obvious a little slotted pipe would not compare in vessel volume or output to an oldshool horn or even a modern "waveguide" on the low end. If you want to sell your Transylvania Tubes then I will buy them.

re: Sonotube - might have too much flex and too little function - the proper way to do a Karlson is as Karlson did with K15/K18/K12 and the 2-way X15 system with an internally mounted K-tube. (Even my K-18 with tube shamed all of my FR on vocals) Greg B's "Karlsonator" can be used if one needs more LF extension.

 

[Rewind]

they're normally made with a cross-section the size of the driver exit, and no flare although the commercial Transylvania Power product ("The Tube") had a downwards sidewall taper of 2 degrees (it sounds great)

here's Karlson's antenna patent for the K-tube. Carl has worked on an oval tube and likes laminated wood veneer for K-tube material

https://www.google.com/patents/US34...a=X&ei=v58OUv3UKOTA2AXbt4HIBQ&ved=0CDYQ6AEwAA

I'd like to know which antenna Karlson made which was advertised in the 1950's as adopted by the U.S. Navy

This may sound arrogant, but I disagree with that old patent. The slit should start closer to the driver. Maybe his drivers did not have a long throat before the opening like the Beyma CP 380/M.

Anyway, I cut away too much now. To achieve that curve is very important for the sound. I will need to redo it now. At least I remember how it looked when it sounded the best.

 

[moray james]

I have tried it now above 3k Hz and a k tube sound real nice. I just opened it up 2mm extra and it was a huge difference. Sound more open now. Tweeter is Beyma CP 380/M.

I noticed it was gradually opening so I closed it. It gave a stronger tweeter sound with more tweeter punch and volume. But it seems to be some kind of dips in frequency curve when using a Behringer CX3400. I am sure I have to overlap some xo points in a minidsp.

Have you tried listening to your paper K-Tubes the way I suggested? Parallel to the floor centred at seated ear level set up on an equal sided triangle so you can look directly down each tube from the listening position. open side of the tube facing inward closed side of the tube facing toward the closest side wall. this has been the best tube position I have tried so far. Mine are one layer of cheap paler and they sound great. Best regards Moray James.

 

[Rewind]

Have you tried listening to your paper K-Tubes the way I suggested? Parallel to the floor centred at seated ear level set up on an equal sided triangle so you can look directly down each tube from the listening position. open side of the tube facing inward closed side of the tube facing toward the closest side wall. this has been the best tube position I have tried so far. Mine are one layer of cheap paler and they sound great. Best regards Moray James.

Yes, maybe. Show me in pictures. I did not get that explanation. I prefer to angle them down into the piece of floor undernieth my chair instead of staring right into the throat.

 

[Rewind]

I'd say the little K-tube is good from 1K6 or so up. Its obvious a little slotted pipe would not compare in vessel volume or output to an oldshool horn or even a modern "waveguide" on the low end. If you want to sell your Transylvania Tubes then I will buy them.

re: Sonotube - might have too much flex and too little function - the proper way to do a Karlson is as Karlson did with K15/K18/K12 and the 2-way X15 system with an internally mounted K-tube. (Even my K-18 with tube shamed all of my FR on vocals) Greg B's "Karlsonator" can be used if one needs more LF extension.

Can always paint it with liquid plastic like polyester. I will probably do that on my Sonotube subwoofer. Thanks for mentioning it!

I cross my k tube at 3500 Hz. I have much better horns and drivers below that.

 

[freddi]

the patent was for antennas - - my example of the X15 system has a fat tube with short parabolic slot and internal scattering section - - another X15 seen had a smaller diameter tube which I'd guess at 1.25" ID

here's a clone of the 1.875" diameter by 7.25" long X15 tube as seen in my cabinets - its in a custom mount and sitting on a K15 - the mount was made so the tube could be mounted on K15's front shelf

An externally hosted image should be here but it was not working when we last tested it.

with the X15 tube or a longer version, inside, my one-off K18 sounded very nice on all vocals
- -- when making tall K-coupler, a de-Q-ing slit instead of a 2/3 height aperture will likely improve subjective "speed" and quality

An externally hosted image should be here but it was not working when we last tested it.

 

[kenpeter]

Anybody else thinking of sonotube Karlsson?

Been there. Done that. Can't say I would recommend it...
Specifically 10" electrovoice on 12" dia tube about 5ft long.
I tried and patched up many different slots to no good end.

The sound is weird, the dispersion pattern is useless for
the covered frequency range unless maybe you are gonna
do something overhead like PhaseIII...

Even then, you need something of a pertuberance inside
the tube near the open end. I never quite got this right.

Still around here somewhere, could probably photograph.
Just find some way to do different, copy mine will not work.

----

I got some rectangular waveguide made of old cans that
had a 2x4 pounded through to shape. I might try with a
KSlot and see if I can still match to a 50ohm transmitter.

I don't figure how the antenna dispersion is same like
Oliver, cause high order modes are quite different for
sounds vs electromagnetic waves. Pressure vs velocity
is not at all similar cause and effect to E vs H... The
inside surface of a radio waveguide must conduct, and
that fact alone should tip off they are not alike...

I once tried to model this in 4NEC2X and never really
got anything that seemed to work out of the simulation.

 

[Rewind]

Then I should I probably stop doing whatever I am doing right now.

 

[Greebster]

I'd like to know which antenna Karlson made which was advertised in the 1950's as adopted by the U.S. Navy

Doubt we'll ever find out as I too would like to know. This work would be classified and his name most likely would never appear. I can think of several applications for this in the '50-60's. Moving forward though I doubt would compete with more modern planar designs. These were coming in the scene in the late 60's. Military/Research is far ahead of what is seen commercially often times by decades. For example the F117 with all of it's facets was developed in 1976 and was shaped that way because they could not model 3D shapes due to antiquated software models. The world became knowledgeable of this aircraft in 1989. Conversely this situation completely changed in 1978 with the advent of new 3D modeling and that produced the B2 bomber in 1980. When did the world become aware of this...? Exactly