500Hz Kugelwellen Horn

[rajagopal_j]

It has been eons since I have actively posted on this forum and I thought it will be fun to get back with documenting this build here.

I have been quite settled with my setup for well more than 10 years now, I think I did a build thread then, I am not sure if its still there. Maybe I should update and do an evolution of my setup over time from open baffles to bass reflex. Anyway while a lot has changed since then some primary components remain, I have had my 425Hz LeCleach .707 hypex horns as the primary horn for more than 10 years now. While making these I did spend time reading JM LeCleach's work and I found that in one of his comparisons he found the Klangfilm Spherical wavefront horns aka Kugelwellen horns to be the best, I have always wanted to make one of those since then.

Fast forward 10+ yrs to about 2 weeks back and I realised I still want to make one. I own a 3D printer (actually 2 printers) so why not! Fire up a dev env and lets code. The idea is to make a 500Hz Kugelwellen horn with a .75 eccentricity for dispersion with a built in filleted flange at the throat to fit it on to my HF driver.

First plot the wave front propagation based on the horn params and get a point cloud


Next, draw triangles and form the shape to make a mesh


Now lets wrap it


This mesh while it looks solid, still doesn't have a thickness, so extrude the outer face and add thickness


The edges are not clean, so clean up in TinkerCad


We need a way to mate with with the HF driver so, Add a mounting Flange and fillet joint for strength in OpenScad



Finally time to print, but it has to be split into 2 pieces to fit the bed.




Next to the current LeCleach horn to give a better idea of size. The LF is 15 incher, the LeCleach horn is ~16in in diameter.


Now for the most painful part of this build sanding, priming, welding the halves and painting. The inside profile has to be super smooth. Lots of work done, a lot more to do!

More as I make progress!

 

[square_wave]

Nice to see this. What other options are there apart form 3d printing to make horns like this? I have seen painstaking efforts with wood by German horn makers.

 

[rajagopal_j]

Nice to see this. What other options are there apart form 3d printing to make horns like this? I have seen painstaking efforts with wood by German horn makers.

We can make this in wood as well, CNC is the best option for this. We can turn the horn separately then make a flange to spec and mate them. We can also cast it in fibreglass, but we will have to still make a POP model based on the designs and then make a mould and then cast. Given this is an elliptical design 3D printing is one of the best bets, if we have access to a 500mm bed printer this can be printed in one piece.

 

[Vineethkumar01]

Congrats for the nice prints... Overall Nice looking speakers in the background.

Are the horn profiles computed using Dr Bernd Ahler's (docali) spread sheets?

DrBA Calculator and BEM Simulation | sphericalhorns.net

Also, for general info, docali himself has developed even better horns (in terms of smoother directivity transition and acosutic loading optimization) like the WN300.
Any reason why this specific horn profile was chosen?

Other comparable (maybe even better in terms of directivity profiles) are the ones here: https://at-horns.eu/

If one is after constant directivity horns with 90 degree beamwidth (in horizontal plane), these are among the best as well:

X-Shape

audiohorn.net

 

[rajagopal_j]

Congrats for the nice prints... Overall Nice looking speakers in the background.

Are the horn profiles computed using Dr Bernd Ahler's (docali) spread sheets?

DrBA Calculator and BEM Simulation | sphericalhorns.net

Also, for general info, docali himself has developed even better horns (in terms of smoother directivity transition and acosutic loading optimization) like the WN300.
Any reason why this specific horn profile was chosen?

Other comparable (maybe even better in terms of directivity profiles) are the ones here: https://at-horns.eu/

If one is after constant directivity horns with 90 degree beamwidth (in horizontal plane), these are among the best as well:

X-Shape

audiohorn.net

Thanks Vineet, I recently read some of your threads, your work its pretty good.

This horn was designed ground up based on the original wavefront propagation formulas developed by Klangfilm. Same as the DRBA link you sent, there is nothing new in there, the work was done a long time ago by the the klangfilm guys.

The primary source of inspiration is this presentation by JMLC
https://pearl-hifi.com/06_Lit_Archi...eCleach_Jean-Michel/Horn_Shootout_ETF2010.pdf

This came out in 2010 around that time I had just setup the LeCleach horns, which is the round horn you see in the picture. I have always wanted to make a spherical wavefront profile, just got around to it.

 

[Vineethkumar01]

@rajagopal_j : Thank you
Wishing you all the best with this project

 

[srinisundar]

Nice and look forward to see them singing on your setup soon.

Regrds

 

[arunvenkats]

Wow. Love the way your design evolved. Thanks for sharing.

Regards,
Arun

 

[drba]

Thanks Vineet, I recently read some of your threads, your work its pretty good.

This horn was designed ground up based on the original wavefront propagation formulas developed by Klangfilm. Same as the DRBA link you sent, there is nothing new in there, the work was done a long time ago by the the klangfilm guys.

The primary source of inspiration is this presentation by JMLC
https://pearl-hifi.com/06_Lit_Archi...eCleach_Jean-Michel/Horn_Shootout_ETF2010.pdf

This came out in 2010 around that time I had just setup the LeCleach horns, which is the round horn you see in the picture. I have always wanted to make a spherical wavefront profile, just got around to it.

Your post needs some clarifications. You claim that there is nothing new in my work concerning spherical wave horn?

This is simply not true!

The original publications never worked with elliptical or super elliptical shapes. This is because ellipsoidal wave fronts are very complicated to handle mathematically:

Ellipsoidal Wave Fronts in Horns | sphericalhorns.net

Besides this I only mention the PETF algorithm never seen before with this horn type any many other features.

If you have only introduced a "little" eccentricity, then you have most probable failed to create an elliptical swh and you may have only created somewhat like an elliptical wave guide. You could simply validate your results if you show us a BEM simulation with the radiation impedance of your horn and the hrz and vrt polar.

 

[drba]

Looking at the point clouds in the first post, I'd bet a lot that they were created on my computer. Here are similar results:




The point cloud pattern is exactly the same as generated in my calculator. The algorithm to produce this pattern is quite unique. So if you used my calculator, I would appreciate it if you respect my intellectual property and name the tools used.

And again, this newly work was never done by Manfred Harsdorff or others. They never handled ellipsoidal wave fronts and they never used elliptical shapes.

Btw, the intrinsic rollback for swh is an integration waste in most cases. So one could use the merge with horn option like this:

 

[drba]

And jmlc never said that swh is better than his own profile. He always preferred his own jmlc construction procedures. But give similar results just up to mouth region but the jmlc profile is more efficient giving smaller shapes.

What you refer to is a shootout for ETF where different horns with different drivers were compared. For a valid comparison, you need to use the same driver attached to different horns.

 

[drba]

Looking at the point clouds in the first post, I'd bet a lot that they were created on my computer. Here are similar results:

Sorry, I meant that there were generated with my shared swh calculator.

 

[Vineethkumar01]

Welcome @drba to this forum..

Hope you remember me from this project..


Sincerely hope that all of us here learn more about horns from you and use more of your designs..

 

[drba]

Welcome @drba to this forum..

Hope you remember me from this project..
View attachment 91795

Sincerely hope that all of us here learn more about horns from you and use more of your designs..

I remember of course your contribution to this project and I hope the owner is still satisfied with the sound ;-)

imo this is one of best implementations of fin horns combined with a bass bin i know of. This is not only by using my mk3b2 but I think the bass unit is great design because combines many properties for a good overall result. The short front horn provides some loading and directivity control and it shifts back the woofer so that compression driver and woofer sound origin come closer together. Again, this is great design.

 

[Nikhil]

It has been eons since I have actively posted on this forum and I thought it will be fun to get back with documenting this build here.

I have been quite settled with my setup for well more than 10 years now, I think I did a build thread then, I am not sure if its still there. Maybe I should update and do an evolution of my setup over time from open baffles to bass reflex. Anyway while a lot has changed since then some primary components remain, I have had my 425Hz LeCleach .707 hypex horns as the primary horn for more than 10 years now. While making these I did spend time reading JM LeCleach's work and I found that in one of his comparisons he found the Klangfilm Spherical wavefront horns aka Kugelwellen horns to be the best, I have always wanted to make one of those since then.

Fast forward 10+ yrs to about 2 weeks back and I realised I still want to make one. I own a 3D printer (actually 2 printers) so why not! Fire up a dev env and lets code. The idea is to make a 500Hz Kugelwellen horn with a .75 eccentricity for dispersion with a built in filleted flange at the throat to fit it on to my HF driver.

First plot the wave front propagation based on the horn params and get a point cloud
View attachment 89698 View attachment 89699

Next, draw triangles and form the shape to make a mesh
View attachment 89700 View attachment 89701

Now lets wrap it
View attachment 89702 View attachment 89703

This mesh while it looks solid, still doesn't have a thickness, so extrude the outer face and add thickness
View attachment 89704 View attachment 89705

The edges are not clean, so clean up in TinkerCad
View attachment 89706 View attachment 89707

We need a way to mate with with the HF driver so, Add a mounting Flange and fillet joint for strength in OpenScad

View attachment 89708

Congratulations @rajagopal_j on a nice build!

Can you please clarify if you have used @drba's model?
If so it is only fair that you give credit in your posts for the Intellectual Property.


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