45 degrees is perfect, these were supposed to be pointed up 30 degrees with the slot pointing at the listener. There are some pictures in the beginning of this thread.
The K-Tube was inspired by Freddi - it should be similar to the Transylvania Power Company K-Tube. Freddi presents it here in the video: YouTube
It is a half ellipse wrapped to a tube shape. Or at least it should be, I think there is some minor deviation due to the way I created the 3D model.
The K-Tube was inspired by Freddi - it should be similar to the Transylvania Power Company K-Tube. Freddi presents it here in the video: YouTube
It is a half ellipse wrapped to a tube shape. Or at least it should be, I think there is some minor deviation due to the way I created the 3D model.
Last edited:
I tried to split the slot into two. I am not sure if this is correct, the expansion does not seem like that. I need to do the math properly and see the difference - my aim is exponentially expanding slot cut in half. This is an attempt to make the vertical pattern symmetrical and it is meant to be mounted behind a baffle with the CD mounting screws.
Attachments
I did both 30deg (first 3 pics) and 45deg tilts (next 3 pics).
SPL curves are at 1m and the polars are at 3m normalized. You can see the vertical polar rising with freq and asymmetric from the slot. The horizontals are very wide which is expected from obs fields.
The last pic is the vertical without normalization (raw) which shows this better IMO.
.
Attachments
Last edited:
That is really awesome! Here are my measurements to compare. Zero is here the axis of the tube and below means the side with the slot, it was pointed with the slot down when I tested them (but it may be the opposite, I do not remember exactly...). So the simulation confirms, that the ripple is inherent to the tube.
Edit: Dual slot tube picture attached, now made properly. This one will be printed
Edit2: In these measurements, the rotating point was not exactly at the end of the tube.
Edit: Dual slot tube picture attached, now made properly. This one will be printed
Edit2: In these measurements, the rotating point was not exactly at the end of the tube.
Attachments
Last edited:
- absolutely amazed to see DonVK's simulations - FWIW, "The Tube" by Transylvania Power Company had a 2 degree downwards slope to its sidewalls and a bit narrower slot (at the nose) than a straight pipe with half ellipse pattern. It was surmised that perhaps that was done to make things easier with the mold but Walter Alan Zintz explained that taper was in compliance with Karlson's first Acoustic Transducers patent application (1951) with tapered chamber.
US2816619A - Acoustic transducers
- Google Patents
US2816619A - Acoustic transducers
- Google Patents
Last edited:
with regards to the 2-slot tube, Robert Reams had a version in 1979 using a 12 inch speaker and that "Clothespin" sat on top of Robert's "Karlson - Hypex" bass enclosure. Rather than being arranged like Karlson's asymmetric projector, the Karlson - Hypex had a tapered slot at the throat of a short horn.
Acoustic transducer having multiple frequency resonance 1979
US4196790A - Acoustic transducer having multiple frequency resonance
- Google Patents
Acoustic transducer having multiple frequency resonance 1979
US4196790A - Acoustic transducer having multiple frequency resonance
- Google Patents
Very interesting! For combining inside a MF horn, two shorter straight tubes would work better than just one bent. There are some pictures here: https://www.diyaudio.com/forums/mul...exit-driver-hf-unit-source-3.html#post6040929 and in post 49 of that thread. I might try some slight tapering in the first part that goes through the horn wall to make the tube slimmer, the length would be so that the tips almost touch and again, a half ellipse slot. Two HF drivers will be a better match for the insanely sensitive JBL2445. The disadvantage is I will need 4 in total. Maybe 4 DE7 or DE5 would work well with slimmer 0.75" or 0.5" ID tubes.
The dual slot tube is printed and ready for some measurements It is meant to be placed from the backside of the baffle held through the baffle with CD mounting screws.
Edit: I am looking for a way to share the designs effectively, most probably on Thingiverse, if they sort out the performance problems.
The dual slot tube is printed and ready for some measurements
It is meant to be placed from the backside of the baffle held through the baffle with CD mounting screws.Edit: I am looking for a way to share the designs effectively, most probably on Thingiverse, if they sort out the performance problems.
Attachments
Last edited:
its interesting also to look at Karlson's "Open End Waveguide Antenna" patent
https://patentimages.storage.googleapis.com/0b/3f/f3/ba462c85c48ff9/US3445852.pdf
https://patentimages.storage.googleapis.com/0b/3f/f3/ba462c85c48ff9/US3445852.pdf
So here are some measurements with the dual slot tube on a paper baffle. The slot is oriented horizontally. The measurements show that it should most probably be oriented with the slot vertically while actually in use. As all my measurements, please take them with a grain of salt. I plan to set up another room for the measurements or do the measurements outside, so that will hopefully improve one day. But all in all, I think this might make an interesting waveguide for a tweeter, 3 kHz up.
Attachments
it will be interesting to hear your subjective impressions of the single slot tube vs double slot type. Sometime I want a new 10" or 12" coupler which can use an internal tube. (any ideas ?)
This 41.5" tall K which currently loaded with an EVM18B plays very nice and did also with Eminence 18" - It probably
would be good with some 15" speakers. It has a curved upper reflector. I just don't like its looks - maybe if made aboot
36 inches tall it would look better.
Your K15 made some very nice graph traces.
The internal tube mounting hole can be seen at the bottom of the reflector panel.
A 12 inch version which plays smooth would be fun augmented with subwoofer.
The Karlsonator variant by GregB could probably sport an internal K-tube up in its stub section.
See the upper part of the aperture where it narrows to a point - If that is blocked say 8 inches down
from the top, the sound up close loses subjective "air" and some "speed" - its very agile sounding
with the full aperture.
This 41.5" tall K which currently loaded with an EVM18B plays very nice and did also with Eminence 18" - It probably
would be good with some 15" speakers. It has a curved upper reflector. I just don't like its looks - maybe if made aboot
36 inches tall it would look better.
Your K15 made some very nice graph traces.
The internal tube mounting hole can be seen at the bottom of the reflector panel.
A 12 inch version which plays smooth would be fun augmented with subwoofer.
The Karlsonator variant by GregB could probably sport an internal K-tube up in its stub section.
See the upper part of the aperture where it narrows to a point - If that is blocked say 8 inches down
from the top, the sound up close loses subjective "air" and some "speed" - its very agile sounding
with the full aperture.
Last edited:
