if directional sound is what your after check this out What Makes a Sound Source Directional | Holosonics
Found it here: extremely narrow directivity speaker design, great thread! The discussion of parabolic dishes seems really appropriate.
@Turk182 I did find Holosonics during my research under "audio spotlight" search results. How is the frequency range and amplitude of audible frequencies that are generated by ultrasonics? It seems (gut feeling) like producing high levels of audible sound that a considerable, higher level of ultrasonic energy would need to be sent.
I guess one might invite Weltersys (Art Welter) into this discussion on what that one might make which is simple and practical using a parabolic - hyperbolic reflector.. ( could use some tips on focusing a reflector in Karlson based projects)
Charlie Watkins
extremely narrow directivity speaker design
A Karlson device might be used but they are supposed to spread , not focus sound.
this was loud and clear 150 feet away with an 8 inch Sammi whizzer cone speaker/ Up close , a lot of stuff rattling around in the front chamber. It wold be good when making such things to have the wings removable for adjustments
karlson projector speaker - YouTube
Here's some dims for a 12 inch klam scaled from that 8 klam in the old video - an 8" klam would be easy to carry
and perhaps made from a cardboard tube plus plywood
https://i.imgur.com/GSP8OTV.jpg
Charlie Watkins
extremely narrow directivity speaker design
A Karlson device might be used but they are supposed to spread , not focus sound.
this was loud and clear 150 feet away with an 8 inch Sammi whizzer cone speaker/ Up close , a lot of stuff rattling around in the front chamber. It wold be good when making such things to have the wings removable for adjustments
karlson projector speaker - YouTube
Here's some dims for a 12 inch klam scaled from that 8 klam in the old video - an 8" klam would be easy to carry
and perhaps made from a cardboard tube plus plywood
https://i.imgur.com/GSP8OTV.jpg
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if you ever want to play with a Karlson projector as an art-music project, I think one could be made cheap from a cardboard concrete form and plywood for the aperture-baffle and back plate.
My klam 8 sounded pretty dull up close but decent at 150 feet. The Sammi 8 iinch had a 1.5" voice coil so could probably take more power than say Viaton's BG20
The angle might be 40 degrees up from horizontal.
https://i.imgur.com/LNw8kXp.jpg
My klam 8 sounded pretty dull up close but decent at 150 feet. The Sammi 8 iinch had a 1.5" voice coil so could probably take more power than say Viaton's BG20
The angle might be 40 degrees up from horizontal.
https://i.imgur.com/LNw8kXp.jpg
Work in progress. Building the first horn version with two 90mm drivers that I have on hand. 1200mm overall length.
Based on other projects on this forum, decided the fastest way to test the concept was paper mache. Designed the pattern in Rhino3D and unrolled it. Laid out on a thick paper that was printed on one side. Built a wood battened cone and laminated thin wood into supporting rings around it. The Y channel plug was built from EPS 100mm rods, cut to the angles determined by the CAD. Applied a few layers of paper mache, thick rice paper, then craft paper, wrapped the top section with soaked rough twine to get a thicker stiffer core and craft paper sandwiched it. Wood rings for speaker mounting. Finally colored paper to make it less scary looking when I am out in the world bouncing noise. Construction photos.
Conical horn finished weight is 1.4 kilos, has a good feel to it, wood keeps the shape very well. Sealing the speaker housings in and testing today.
Based on other projects on this forum, decided the fastest way to test the concept was paper mache. Designed the pattern in Rhino3D and unrolled it. Laid out on a thick paper that was printed on one side. Built a wood battened cone and laminated thin wood into supporting rings around it. The Y channel plug was built from EPS 100mm rods, cut to the angles determined by the CAD. Applied a few layers of paper mache, thick rice paper, then craft paper, wrapped the top section with soaked rough twine to get a thicker stiffer core and craft paper sandwiched it. Wood rings for speaker mounting. Finally colored paper to make it less scary looking when I am out in the world bouncing noise. Construction photos.
Conical horn finished weight is 1.4 kilos, has a good feel to it, wood keeps the shape very well. Sealing the speaker housings in and testing today.
Thanks!! I appreciate the links. I see the new activity now. The Karlson form will be the next test platform I'll work on, cannot quite wrap my head as easily around it as the horn and parabolic, but it is easy to fabricate and hear the results.
Parabolic is the third method. That seems to be the most promising based on the directions and previous experiments and products introduced to the market. Physical balance-wise I find the Cassegrain variation of interest. Two reflectors with the speaker facing forward.
just in case you wish a horn for part of your home listening situation
DIY Paper Mache Horn - The Paper Horn by Inlow Sound
DIY Paper Mache Horn - The Paper Horn by Inlow Sound
Titebond glue for some layers, yellow tint though. White wood-working glue for the rest. Almost two liters! Diluted with about a third of water. Nitrile gloves and finger wetting each side as opposed to soaking it which left it all too wet to work with easily.
That is where I got the original inspiration. Beautiful build, I got hung up for a short period thinking I needed as perfect a form to build on, looked at getting a turned wood plug made.
(rendering) that was not reasonable or fast. Then I saw some rougher paper mache horn projects and forged ahead. It is not going to be the final design, better to bash one out and see. 🙂
I can't draw, never did art other than a lopsided mache speaker head for 5 inch driver plus a Vulture-na-gig made with copper tubing, wire and paper mache - never got finished.
paper mache if strong would really be fun for little Karlson type speakers and "K-tube"
paper mache if strong would really be fun for little Karlson type speakers and "K-tube"
Attachments
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Design-wise, going to use PVC pipe as the basis. Matching that diameter about 100mm / 4". Sourcing the driver for that, Dayton Audio most likely. I have a contact in China that can source for me, so will take a look at what is available.
Here's Karlson's AP100 as sold by Jess Oliver as the "Magna-Clam". I believe a set were installed at Radio City Music Hall in their day
https://i.imgur.com/0jkMvLW.jpg
https://i.imgur.com/0jkMvLW.jpg
Hi Art
Regarding use of a parabolic umbrella -
What and where are the losses "through" the umbrella?
Could one use the umbrella as a mold or at least an armature with fiberglass & epoxy or wood glue and paper mache to reduce losses?
Is there a practical way to retain folding and line it with something to reduce losses?
A Faital 3fe25 or 3fe22 done like that article would work.
I'm still trying to find a larger bowl than 22" with appropriate shape but no luck so far.
Regarding use of a parabolic umbrella -
What and where are the losses "through" the umbrella?
Could one use the umbrella as a mold or at least an armature with fiberglass & epoxy or wood glue and paper mache to reduce losses?
Is there a practical way to retain folding and line it with something to reduce losses?
A Faital 3fe25 or 3fe22 done like that article would work.
I'm still trying to find a larger bowl than 22" with appropriate shape but no luck so far.
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Following Art's #14 post in extremely narrow directivity speaker design looking up Curtis Graber's Hyperspike patents in published documents. Very interesting approach.
They invert the parabolic dish and put multiple speakers around the rim.
The spike in the middle of the dish. Appears to be more like an angel food cake pan in the production product. More central column surface to bounce off of.
Large transducers in the production model. Appears to drive a piston-like plate moving air into the rim of the inverted horn?
They invert the parabolic dish and put multiple speakers around the rim.
The spike in the middle of the dish. Appears to be more like an angel food cake pan in the production product. More central column surface to bounce off of.
Large transducers in the production model. Appears to drive a piston-like plate moving air into the rim of the inverted horn?
Functional prototype for testing. Indoor test cable tethered to amp initially. Works really well! It paints the synth sound around the room as expected. Will have to try in a larger outdoor acoustically reflective space to see the effect of distance and spread. Right now if you close your eyes and move the sound pattern around the room you can feel the space in a way that is completely new. As the operator of the device, you feel the main low frequencies close and the main sound being directed back to your ears.
Working on the portable amp and battery now.
The bowls are actually insulated double wall shells, quite a nice little containment.
Working on the portable amp and battery now.
The bowls are actually insulated double wall shells, quite a nice little containment.
That's great and looks great / "interesting" too. I'll have to read up on those patents.
That's a cool looking little coax you're using too.
That's a cool looking little coax you're using too.
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