simple and good sounding - for starters I'd suggest a tube 1"ID by ~5.3" long with a half ellipse slot. The slot is
full length and would have a 1/8" starting gap. Paper could be good for proof of concept.
There would be no EQ contouring needed with a decent 1" format compression driver.
the tube is usually tilted 12-30 degrees above (or below if slot facing "up) from horizontal
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full length and would have a 1/8" starting gap. Paper could be good for proof of concept.
There would be no EQ contouring needed with a decent 1" format compression driver.
the tube is usually tilted 12-30 degrees above (or below if slot facing "up) from horizontal
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.
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.
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.
http://img502.imageshack.us/img502/9215/hak18ktube440.jpg/img]
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Cool,
Reminds me the agroanalysis tool
Reminds me the agroanalysis tool
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First K-tube Test - Easy
So I decided to test this K-tube concept out - it is simple enough: I took a 1in dia plastic tube from an old toy, took scissors and cut the slotted aperture, or should I say Kut the K-aperture?
Anyhow, the tube was about 5.5in long with a 5in long aperture. Then secured the tube using modeling clay to a 1 in dia throat PRV D280Ti compression driver. I made the measurement 0.5m away at 30 deg angle from axis of tube but aligned with K-slot. The resulting measurement surprised me with how flat it was and listening to it XO at 2.5kHz with an 8in Beta 8CX (no CD) in an XKi was downright pleasant. The most impressive thing was how wide and uniform the polar dispersion was. I did not have time for a polar measurement but walking around the room, could hear that it was very uniform over +/-70 deg or 140 deg wide. There is a fall-off int he HF's but I later found out it's because I did not have the K-tube oriented properly. I had it pointing straight up as shown in the photo with mic, the tube should be aimed up about 30 deg from horizontal with aperture facing down and mic level. Freddi. do you have some data that shows how flat it is and how high up it can go?
Photo of the setup:
Here is frequency response and phase:
Here is the harmonic distortion:
Here is the impulse response:
Summary: a very smooth sounding "horn" that is dirt cheap and brain dead easy to make. I have heard that even a cardboard tube can work. My next step will be to print one on a 3d printer with a CD bolt flange. Highly recommended that you give it a try - it looks funny but it really works. I am in the process of making a 90x40 deg SEOS waveguide and will compare the two at some point.
So I decided to test this K-tube concept out - it is simple enough: I took a 1in dia plastic tube from an old toy, took scissors and cut the slotted aperture, or should I say Kut the K-aperture?
Anyhow, the tube was about 5.5in long with a 5in long aperture. Then secured the tube using modeling clay to a 1 in dia throat PRV D280Ti compression driver. I made the measurement 0.5m away at 30 deg angle from axis of tube but aligned with K-slot. The resulting measurement surprised me with how flat it was and listening to it XO at 2.5kHz with an 8in Beta 8CX (no CD) in an XKi was downright pleasant. The most impressive thing was how wide and uniform the polar dispersion was. I did not have time for a polar measurement but walking around the room, could hear that it was very uniform over +/-70 deg or 140 deg wide. There is a fall-off int he HF's but I later found out it's because I did not have the K-tube oriented properly. I had it pointing straight up as shown in the photo with mic, the tube should be aimed up about 30 deg from horizontal with aperture facing down and mic level. Freddi. do you have some data that shows how flat it is and how high up it can go?Photo of the setup:
Here is frequency response and phase:
Here is the harmonic distortion:
Here is the impulse response:
Summary: a very smooth sounding "horn" that is dirt cheap and brain dead easy to make. I have heard that even a cardboard tube can work. My next step will be to print one on a 3d printer with a CD bolt flange. Highly recommended that you give it a try - it looks funny but it really works. I am in the process of making a 90x40 deg SEOS waveguide and will compare the two at some point.
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xrk971,
Nice enough attempt - but I think you'll find it measures and sounds even better with a slower flare aperture and straighter, more rigid walls. As freddi often said, schedule 40 PVC is pretty good for this. Draft, print and cut a half-ellipse pattern to wrap around the tube, mark the edges with a pen and cut with a dremel type tool. It should make for a more gradual transition to free-air and fewer reflections.
Here are a few measurements I performed on the Transylvania tube.
This one was using a Samson GoMic, which I believe rolled-off a bit above 14-15kHz, but nothing awful. Taken a meter or two away IIRC, it's been a few years. Same tube on three different compression drivers. Tube pointing ~20° up, slot down. There was a ~1.5kHz PLLXO.
This one was with calibrated UMM-6, but pretty near-field, maybe 10" or so. Same compression driver (BMS4550), naked (blue) vs tube on (red). A little something going on around 2kHz on the distortion plot.
We can see the tube seems to offer some load down to 700Hz as per the reduced distortion.
Little to no contouring needed with the K-Tube usually, will mostly depend on the compression driver. Power response is pretty good subjectively, I never measured much off-axis. It's different from the CD-waveguides I like a lot, as the dispersion is all over the place because of diffraction instead of ~90°.
Nice enough attempt
- but I think you'll find it measures and sounds even better with a slower flare aperture and straighter, more rigid walls. As freddi often said, schedule 40 PVC is pretty good for this. Draft, print and cut a half-ellipse pattern to wrap around the tube, mark the edges with a pen and cut with a dremel type tool. It should make for a more gradual transition to free-air and fewer reflections.Here are a few measurements I performed on the Transylvania tube.
This one was using a Samson GoMic, which I believe rolled-off a bit above 14-15kHz, but nothing awful. Taken a meter or two away IIRC, it's been a few years. Same tube on three different compression drivers. Tube pointing ~20° up, slot down. There was a ~1.5kHz PLLXO.
This one was with calibrated UMM-6, but pretty near-field, maybe 10" or so. Same compression driver (BMS4550), naked (blue) vs tube on (red). A little something going on around 2kHz on the distortion plot.
We can see the tube seems to offer some load down to 700Hz as per the reduced distortion.
Little to no contouring needed with the K-Tube usually, will mostly depend on the compression driver. Power response is pretty good subjectively, I never measured much off-axis. It's different from the CD-waveguides I like a lot, as the dispersion is all over the place because of diffraction instead of ~90°.
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I also think the flare needs to be slower on XRK971's tube - - as tight as "this" cut into a schedule 40 1-inch pipe seems to work OK
here's a DE25 - its cuts off sharply past 17KHz whether on horn, or K-tube
they aren't "CD" - there's two interacting planes - subjectively a K-tube can sound more open than a WG plus they seem to allow close listening conditions.
my first tube over a decade ago was paper.
there's a fairly smooth rolloff perpendicular to the a long axis.
for a fun comparison - try a mini klam on your compression drivers
here's a homemade ~5.3" long thin-wall tube with a 1.7" or so unslotted extension compared to Carl's 9" long by 1.875"ID tube
made like one Karlson X15 tube which had an internal scattering device. The big tube measured pretty rough yet
subjectively sounds good - something like a plate lens. Carl claims it has to be measured in a number of spots to
get the picture.
HF cutoff was low due to using an Eminence CD8 compression driver (those had aluminum diaphragms vs later titanium)
Karlson apparently experimented with different diameters and approach
for some reason, adding the little "stub" seemed to introduce a response notch
like skinny unmounted horn, a baffle at the compression driver is sometimes useful
a one-inch to two inch conical horn adapter would smooth out the response of the larger tube below
An externally hosted image should be here but it was not working when we last tested it.
here's a DE25 - its cuts off sharply past 17KHz whether on horn, or K-tube
they aren't "CD" - there's two interacting planes - subjectively a K-tube can sound more open than a WG plus they seem to allow close listening conditions.
my first tube over a decade ago was paper.
there's a fairly smooth rolloff perpendicular to the a long axis.
for a fun comparison - try a mini klam on your compression drivers
An externally hosted image should be here but it was not working when we last tested it.
here's a homemade ~5.3" long thin-wall tube with a 1.7" or so unslotted extension compared to Carl's 9" long by 1.875"ID tube
made like one Karlson X15 tube which had an internal scattering device. The big tube measured pretty rough yet
subjectively sounds good - something like a plate lens. Carl claims it has to be measured in a number of spots to
get the picture.
HF cutoff was low due to using an Eminence CD8 compression driver (those had aluminum diaphragms vs later titanium)
Karlson apparently experimented with different diameters and approach
An externally hosted image should be here but it was not working when we last tested it.
for some reason, adding the little "stub" seemed to introduce a response notch
like skinny unmounted horn, a baffle at the compression driver is sometimes useful
a one-inch to two inch conical horn adapter would smooth out the response of the larger tube below
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.
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Looking forward to your comparison.
Quite a few years ago now I compared an Eminence PSD2002 on both an H290 horn and a 6.5" K-tube. The K-tube was the clear winner. It was subjectively less colored and more realistic sounding, and believe it or not it measured better as well. It sounded very open, a bit like a (good) dome midrange, but with more extension, better dynamics and good details. I am a little skeptical about the power handling qualities for pro use, but for home use with a comp driver, K-tubes rule.
My K-Tubes (on EV DH1A drivers) are made from a single piece of 1/4" graph or notebook paper just one wrap and some tape. I do use a simple wire hoop made from twist tie wire (burn the paper off) to keep m tube round. You can see in the photo above how the plastic K-Tube wants to open up and gets distorted. A little hoop of wire keeps it in a nice tubular shape . I use a double cutaway tube design which looks like a bishops cap. I don't plan to switch back to horns any time soon. K-Tubes are the best I have ever heard never heard a horn that would make me switch. Kount me in a a K-Tube kfan (the k is silent). Best regards Moray James.
attached picture of plastic single and double cutaway tubes . picture of paper single cut away with wire hoop to retain shape. The paper k-tubes sound excellent. Just for scale that is a 2" id. tube on the EV DH1A.
attached picture of plastic single and double cutaway tubes . picture of paper single cut away with wire hoop to retain shape. The paper k-tubes sound excellent. Just for scale that is a 2" id. tube on the EV DH1A.
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a 5.3" long tube with a bit of extension is long enough to mount internally in a K12 to make an "X12" - I never experimented with shorter lengths - wonder how those would do?
here's Alan Weiss's lens some years back for an Eminence bolt on compression driver - from what I understand, Alan worked with Karlson.
I made one of posterboard and masking tape - seems ok - there was a story where a speaker using the mini-klam
was auditioned - the description was that the lens spread highs everywhere - so not suitable for THX standards
here's Alan Weiss's lens some years back for an Eminence bolt on compression driver - from what I understand, Alan worked with Karlson.
An externally hosted image should be here but it was not working when we last tested it.
I made one of posterboard and masking tape - seems ok - there was a story where a speaker using the mini-klam
was auditioned - the description was that the lens spread highs everywhere - so not suitable for THX standards
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That is sort of like a Klam? My one experience with a small Klam for a 3.5in driver wasn't so good. The relative size is real important otherwise you get echo like sound from full range.
But then a Karlsonator is much bigger and sounds great with wide even polars.
hey Moray - does that description of the wings fit "this"?
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Really ? Obstruction of the ( sound) source is the first thing that I see in those..
No Fred...
I splay the tapers out to the left and right side walls just as they are approaching the top of the driver. They still provide lots of load on the driver but the driver is ntr firing into a reflective chamber. Sorry I don't have a picture for you but no camera no pictures. the bottom of the tapers more or less end up parallel to the bottom of the cabinet. Hope that helps. Best regards Moray James.
I splay the tapers out to the left and right side walls just as they are approaching the top of the driver. They still provide lots of load on the driver but the driver is ntr firing into a reflective chamber. Sorry I don't have a picture for you but no camera no pictures. the bottom of the tapers more or less end up parallel to the bottom of the cabinet. Hope that helps. Best regards Moray James.
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my camera is lost - I understand what you're saying and have "raised" the bottom intercept of the aperture - that didn't matter on a little coupler stuffed with 18",
it would be interesting to see if the truncated aperture affects the cavity peak
here's my one-off K-coupler with 18" speaker and somewhat less confined aperture
here's KenL's "K8" with pretty much what you suggest - it did not measure smooth until he
added a cavity (not shown) - good trick considering an Eclipse W0838R.
I suspect the Karlsonators work something like the extra chamber plus the action of offset driver path.
it will be interesting to see how well MMJ's "Karlflex" fares objectively and in measurements.
it would be interesting to see if the truncated aperture affects the cavity peak
here's my one-off K-coupler with 18" speaker and somewhat less confined aperture
An externally hosted image should be here but it was not working when we last tested it.
here's KenL's "K8" with pretty much what you suggest - it did not measure smooth until he
added a cavity (not shown) - good trick considering an Eclipse W0838R.
I suspect the Karlsonators work something like the extra chamber plus the action of offset driver path.
it will be interesting to see how well MMJ's "Karlflex" fares objectively and in measurements.
An externally hosted image should be here but it was not working when we last tested it.
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