WE KS-6368

So, I've obsessing over this horn for a while. Took some time to read up in the "Horn" book and did quite a bit of internet searches.

Despite the "KS" designation, the horn was manufactured by Racon for Western Electric. It was designed in 1928 as a more compact replacement for the straight 6-A horn. At the time, Racon held the patents for manufacturing horns using impregnated woolen fabric that was baked.

Excerpt from the book of a written account by J.J. Kuhn of Bell Telephone Laboratories:
"The horn was made of a material similar to canton flannel such as is used for underwear, the process being to make a form of wood or metal following the inner contour of the shape desired and then slipping over this form a boot having the once general shape of the desired one. This boot is made of the flannel and of such dimensions that it fits the form very snuggly. After the boot is in place the entire form is soaked with a special preparation with has the appearance of a very thick glue or shellac, and after being soaked a second boot is slipped over the forms. This is then also impregnated with the material and the entire assembly is then placed in an oven for baking. After baking the forms are removed, the edges trimmed, cracks and depressions filled with cement and the entire horn coated inside and out with a water proof cement. The horn is then given the proper finish, Duco, vanish or whatever finish is desired."

To be continued.
 
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So, the people below claimed an 1:1 copy of the KS-6368. I am not convinced. I have studied numerous pictures of the KS-6368. There is no way that the wooden wall of the inside section of the horn can be made as thin as in the actual horn. It actually looks quite a bit "fatter" therefore obstructing more of the audio path.


IMHO, any reproduction of this horn must maintain the original wall thickness unless a different material is used for the inside piece matching the original's.
 
So, the people below claimed an 1:1 copy of the KS-6368. I am not convinced. I have studied numerous pictures of the KS-6368. There is no way that the wooden wall of the inside section of the horn can be made as thin as in the actual horn. It actually looks quite a bit "fatter" therefore obstructing more of the audio path.


IMHO, any reproduction of this horn must maintain the original wall thickness unless a different material is used for the inside piece matching the original's.
Yeah, that wood horn just flat- out LOOKS wrongezvous.
 
Sad to see such damages... Pictures from a listing on the auction site. It's an opportunity to study the construction of this horn.

Appears to have a metal frame along the edges of the mouth. The nut for mating the driver is attached to a metal flange serving as mechanical/structural support to the horn by mating with the other flange on the inside of the horn. The same metal flange also serves as mounts for the mounting bracket (not shown).
s-l1600 (4).jpg

Broke at the stress point where the horn body is joined with the throat piece. Appears to have two walls: A thinner outer wall and a thicker inner wall. Supports the theory that the throat piece joins the body piece by slipping over it.
s-l1600 (5).jpg

Sad, sad, sad!
 
I love these horns. Vu Audio made a speaker with these... although I didn't hear them.

Lots of vintage and modern driver options for these. I wonder how low they'll go?

It seems like a 3D printer might be the way to make a mold on the bendy parts of the horn. And then maybe an "Inlow Sound" like paper mache method might be a good way to go. In fact, maybe get Johns thought on these... he's a genius with this kind of stuff.
 
I wonder how low they'll go?
Per the "High-Quality Horn Loudspeaker Systems" book, the KS-6368 is a 30", 220Hz horn.

The key to reproducing this horn is to come up with some kind of collapsible mold so that the mold can be collapsed and removed once the outside shell is formed. The original horns were "baked" to cure and dry out the impregnated flannel cloth. 3D printed parts may not survive this baking process. I am thinking about CNC the mold using wood. If the Racon Electric company could do it in 1928, we can surely do it now!? Need an actual KS-6328 to take measurements and create a model to make the wooden molds.

The other option is to use modern materials. One such material is carbon fiber. No idea about the acoustic quality of using carbon fiber for horns. But, looks alone would be killer! :D
 
Came across a rather tatty piece on the big online auction site. Went for it. The horn indeed was made from two pieces. They were just butt joined together and wrapped with thin pieces of something!? I am going to spend a ton of time taking careful measurements and make observations. :)

IMG_5032.jpgIMG_5028.jpgIMG_5029.jpgIMG_5031.jpg
 
Simply awesome!

I heard one of these in a mono system and was impressed, im guessing you wont be able to 3d print at least some of the parts due to size, ill be very interested in following this project. Good luck!
 
Great stuff. I'm thinking wood forms (CNC?) on the first two bends and then paper mache horns. The big horn... make from scratch.

You remind me of this:

Get the hell out of here we got the game on!

 
Thanks guys. Having an actual model that is somewhat close was a key first step. Already have two different approaches in mind as how to build the horn. Will be spending the next couple of weeks to validate measurements and expansion rates. Then, build the horn staying close to original materials/process or using modern materials/process? Yes, CNC wood forms is a key component of either approaches.

Original or modern? What do you guys think?
 

Audionut

Next Round Is On Me
What is the composition, a mixture of fabric and sheet metal?
I imagine it one knew how to weld sheet metal would be easiest, but probably ring like mofo without serious damping. Wood is also possible with serious skill and/or CNC.
 
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