I like the K tube concept but but before attempting a PVC version would like to hear more about fabrication technique, measurement, cutting and etc.
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If not already, load it on your computer as one of these [asc bmp doc dxo gif jpe jpeg jpg mp4 pdf png psd txt zip, though preferably gif?] if possible to upload.
GM
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the way I've made them was to use pvc or abs pipe. Take a printer and try to size an ellipse so a half ellipse pattern will be the desired length of the tube - width (minor axis) = (pi* pipe OD) minus a starting gap - say 1/8" for a one inch format tube like "THE TUBE" by Transylvania Power Co.
Tape the template to the pipe, mark, then cut with a rotary "Dremel" type tool. Then sand the rough edges.
A quick rolled paper tube cut with scissors can be used for POC with one inch compression drivers.
I made a couple of parabolic slot 1.5"ID tubes but didn't get them measured. They probably would measure smooth with 1.4" exit CD.
"THE TUBE" is ~5.3" in length, and its sidewalls taper 2 degrees so its a bit smaller at its end than a straight pipe. Walter Alan Zintz said that probably was done in accord to Karlson's patent (1951 application)
A double slot tube is a strange bird and sounds quite good.
DIY member Reinoutdv has very advanced fabrication skills and high end fieldcoil compression drivers in his exploration of the K-tube - check out the thread below:
Fieldcoil + K-tube
For little cone drivers and tweeter use, I'm more interested in using a "regular" shallow Karlson cavity to enhance horizontal polars.
I think the aperture on Pelanj's lens for 3FE22 could be made tighter
for my cheap but cheerful LaVoce 3" as it has a bit more on-axis rise.
That's a 1.5" pvc tube with parabolic slot in my little K18 with liter test stub.
Tape the template to the pipe, mark, then cut with a rotary "Dremel" type tool. Then sand the rough edges.
A quick rolled paper tube cut with scissors can be used for POC with one inch compression drivers.
I made a couple of parabolic slot 1.5"ID tubes but didn't get them measured. They probably would measure smooth with 1.4" exit CD.
"THE TUBE" is ~5.3" in length, and its sidewalls taper 2 degrees so its a bit smaller at its end than a straight pipe. Walter Alan Zintz said that probably was done in accord to Karlson's patent (1951 application)
A double slot tube is a strange bird and sounds quite good.
DIY member Reinoutdv has very advanced fabrication skills and high end fieldcoil compression drivers in his exploration of the K-tube - check out the thread below:
Fieldcoil + K-tube
For little cone drivers and tweeter use, I'm more interested in using a "regular" shallow Karlson cavity to enhance horizontal polars.
I think the aperture on Pelanj's lens for 3FE22 could be made tighter
for my cheap but cheerful LaVoce 3" as it has a bit more on-axis rise.
That's a 1.5" pvc tube with parabolic slot in my little K18 with liter test stub.
it would be interesting to try something like Pelanj's adoption of MMD for a tweeter. That may take some EQ (?)
Yeah - it sure does resemble some of the multi-tube shotgun mics
For a tweeter (probably a dome tweeter besides compression driver), you could try a little klam. Here is a miserable picture of Alan Weiss's tweeter lens as employed in his "Acoustic Reality" brand surround system.
With the slot oriented as in the picture below, it should be at least as high as ear level and guess could work up right at the top of an average home's wall to ceiling junction.
I bet that sounded pretty good as had Eminence Beta 8 in a little sealed box for the sat speakers in conjunction with Eminence 1" compression drivers. The subwoofer appeared to be a 12" Karlson type with external rear chamber vent.
For a tweeter (probably a dome tweeter besides compression driver), you could try a little klam. Here is a miserable picture of Alan Weiss's tweeter lens as employed in his "Acoustic Reality" brand surround system.
With the slot oriented as in the picture below, it should be at least as high as ear level and guess could work up right at the top of an average home's wall to ceiling junction.
I bet that sounded pretty good as had Eminence Beta 8 in a little sealed box for the sat speakers in conjunction with Eminence 1" compression drivers. The subwoofer appeared to be a 12" Karlson type with external rear chamber vent.
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I tried a little Klam wth a BIC DV52si cab in it. Subjective testing it coupled a little better on low passages. The speaker low is supposedly 70Hz.
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They sound pretty good with the BIC sub woofer in my system. I just did the subjective comparison with my K5/Xki and the BIC didn't do so well. It did a little better in the Klam.
Here's my little K5/Xki's with Bluetooth amp;
Here's my little K5/Xki's with Bluetooth amp;
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Post 6 : the material Pelanj uses should be cut in the same way as the Karlson tube I think.
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Hey EddieT - do you have a rough sketch of your K5 ? - I'd like to see the front cavity shape and depth to the. baffle-"reflector" apex.
No sketch, it's build was at least 25 years ago. Empty cab internal dimensions are 6½w x 8⅛d x 9h. The apex of the baffle and upper panel is 3⅜ in from the wings but the upper panel intersects the top at 1⅜ in from the wings (all measurements in inches).
The baffle was set at 60° and the upper panel probably at 45° with a ⅜ shelf between and now a ¾ vent with an Xki duct.
The baffle was set at 60° and the upper panel probably at 45° with a ⅜ shelf between and now a ¾ vent with an Xki duct.
I appreciate you taking time to give those measurements and bet its really better than scaling the factory K8.
With the Xki inspired duct I am well pleased with the result. I will fine tune the rear chamber padding as soon as I can visit Lowes for some screws. I may use hex head sheet metal screws for ease of driving in/out for experimentation.
I think we all appreciate and thank X for his research and contribution to the success of our projects.
I think we all appreciate and thank X for his research and contribution to the success of our projects.
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Hey Eddie, I'm very grateful for X's Karlson principle works and he will carry those into the future.
You might try a passive K-tube with your FR and XKi 5.
Make a tube of appropriate diameter and length to reach from the dustcap to the main aperture plane - - -have it suspended right over the dustcap (with sufficient gap as to not hit the cone on bass heavy passages). You could roll a paper tube and cut the slot with scissors. This extension is useful with deep Karlson coupler such as the clam/"klam type.
You might try a passive K-tube with your FR and XKi 5.
Make a tube of appropriate diameter and length to reach from the dustcap to the main aperture plane - - -have it suspended right over the dustcap (with sufficient gap as to not hit the cone on bass heavy passages). You could roll a paper tube and cut the slot with scissors. This extension is useful with deep Karlson coupler such as the clam/"klam type.
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What length K-tube do you suggest for the PA130?
BTW I recalled that you mentioned the suspended K-tube back when I asked the K-tube whizzer question. You linked to your Klam video with a Nokie Edwards version of Autumn leaves. I liked it and also Eric Clapton's version with vocal (Eric has a good guitar break). Autumn Leaves is one of my favorites, but I always tear a bit since I lost my wife.
I recall a time when Ulfman's website was the only Google hit for Karlson cabinets. Freddi you have done much to to keep the concept alive.
What length K-tube do you suggest for the PA130?
BTW I recalled that you mentioned the suspended K-tube back when I asked the K-tube whizzer question. You linked to your Klam video with a Nokie Edwards version of Autumn leaves. I liked it and also Eric Clapton's version with vocal (Eric has a good guitar break). Autumn Leaves is one of my favorites, but I always tear a bit since I lost my wife.
I recall a time when Ulfman's website was the only Google hit for Karlson cabinets. Freddi you have done much to to keep the concept alive.
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Another question, since speaker stands are often used have they ever been used as stubs or otherwise as an integral part of the design? I resist stuffed stubs as I strive for efficiency but I can envision a stand tube (cylindrical or rectangle) extending into a cabinet as part of the volume or as a tuned (even slotted stub).
For PA130, a K-slotted tube just long enough to reach or slightly project out of the main aperture.
For klam15 I had the basic 5.3" long slot 1"ID tube extended with straight pipe and jammed down the Eminence C15CX's rectangular horn's mouth. If similar were done with Beta CX, the screen would have to be removed then cement a beveled end tube into the CX horn mouth.
A suspended tube can work for fullrange to help pipe some of the highs out and away from the influence of the chamber.
I really don't think a damped stub connected to the front chamber would adversely affect efficiency. Rather if done right that would add some front chamber volume plus soften a cavity peak and absorb some "echoes" . The stub might built into a stand. Question, for proper effect does the stub have to be connected to the closed end of the Karlson "wedge" where air mass is greatest or can it be placed otherwise such as right below the driver?
For klam15 I had the basic 5.3" long slot 1"ID tube extended with straight pipe and jammed down the Eminence C15CX's rectangular horn's mouth. If similar were done with Beta CX, the screen would have to be removed then cement a beveled end tube into the CX horn mouth.
A suspended tube can work for fullrange to help pipe some of the highs out and away from the influence of the chamber.
I really don't think a damped stub connected to the front chamber would adversely affect efficiency. Rather if done right that would add some front chamber volume plus soften a cavity peak and absorb some "echoes" . The stub might built into a stand. Question, for proper effect does the stub have to be connected to the closed end of the Karlson "wedge" where air mass is greatest or can it be placed otherwise such as right below the driver?