Western Electric KS12027

rogerfederer

Junior Member
Thanks for the kind words. I am far from being on the same level as JE. May take a while... The print was only to test certain concepts. I am still tweaking the design.

Below is a few snap-shots of the latest version.

The wall is now up to 0.2" thick.
View attachment 28470

Cut-away view showing the internal fins. Note that the driver mount plate is remove-able. This is to accommodate different driver styles. (Also, easier for 3D printing purposes.)
View attachment 28472
View attachment 28473

never ceases to amaze:Bow
 
Thanks for the kind words. I am far from being on the same level as JE. May take a while... The print was only to test certain concepts. I am still tweaking the design.

Below is a few snap-shots of the latest version.

The wall is now up to 0.2" thick.
View attachment 28470

Cut-away view showing the internal fins. Note that the driver mount plate is remove-able. This is to accommodate different driver styles. (Also, easier for 3D printing purposes.)
View attachment 28472
View attachment 28473
I bet that 90* was tough to loft.... I may be having faulty memory, but if faulty memory serves, WECO had a straight fully-cellular version as well. (the 12025 is only a cellular throat) Since your are whole hog re-modeling (which is amazing) -- consider deleting the bend. It looks cool, but sound wise getting rid of the bend helps avoid distortion and phase problems, and should not affect the basic formula (those who are hitting calculators may be able to debunk me on this)
 
WECO had a straight fully-cellular version as well
I think you are correct. The 12025 indeed is very similar. Perhaps the 12027 is a shorter version of it? Hmm, I will have to look into it and see.

consider deleting the bend. It looks cool, but sound wise getting rid of the bend helps avoid distortion and phase problems
I too wonder about this. Modeling the bend is not for the faint of heart. From what I could tell, there are differing opinions regarding a straight horn versus a snail horn versus a 90-bent horn. But, the 12027 has another interesting design challenge. Similar to the KS12025, the 90 degree expansion started immediately at the throat. So, between the throat and a few inches away, the 90 degree expansion is faster than the exponential expansion. Then, the exponential expansion takes over. Translation: Starts with a round circle at the throat. Morphs into a rectangular shape. Becomes a thin slit. Then, going into a bowtie shape. I have no idea what all the changing in the wave front areas is doing to the sound. Be as it may, perhaps a straight version of the 12027 is needed?
 
Last edited:
I think you are correct. The 12025 indeed is very similar. Perhaps the 12027 is a shorter version of it? Hmm, I will have to look into it and see.


I too wonder about this. Modeling the bend is not for the faith of heart. From what I could tell, there are differing opinions regarding a straight horn versus a snail horn versus a 90-bent horn. But, the 12027 has another interesting design challenge. Similar to the KS12025, the 90 degree expansion started immediately at the throat. So, between the throat and a few inches away, the 90 degree expansion is faster than the exponential expansion. Then, the exponential expansion takes over. Translation: Starts with a round circle at the throat. Morphs into a rectangular shape. Becomes a thin slit. Then, going into a bowtie shape. I have no idea what all the changing in the wave front areas is doing to the sound. Be as it may, perhaps a straight version of the 12027 is needed?
I vote for that -- my guess is it might be better if you are so bold to rethink Bell Labs' hobby time (WE made little $$ on speakers, it was fun for the engineers!), haha. I can confirm, via ownership the KS 12024 is not the same. The 12024 hybrid-multicell stops at the throat. It's a louder horn made for the last Theater system designed by WECO. Just as weird if not weirder in design... this compact 12027 was perhaps bred for hifi in smaller places. The 12027 is really, dare I say, very similar to an original Smith horn, without vertical flare or a laser-like narrow stance...The Smith white paper predates the 12027 I think(?). Always liked the erie (the erie term I apply more-so to the narrow beam projection of the orig 1940s Smith) sound of these horns. The functional aspect and sound are darn similar as well. They are accurate in a small space, that's for sure, just not for everybody. Bends in horns are usually a form over function thing IMHO. (Sorry everybody -- have been saying 12025 when I meant 024!)
 
Last edited:
So, a fellow Havenite reached out for a pair of the horn for his WE757A cabinets. His cabs already have the WE728B minus the horns. Had to model up the WE757A cabinets for the virtual fit-check. Also, remodeled the horn. Increased the wall thickness to 0.25". Interior vanes start near the throat at 0.050" becoming 0.100" thick at the mouth. Broke the horn up into 6 pieces with tongue and groove features for glueing. The pieces were also welded with a 3D pen to increase strength.

IMG_5476.jpgIMG_5475.jpg62752742055__03CD6D0A-787A-4AD4-9926-B2FEA2CB5ABD.jpg

1605899000325.png1605899027269.png

It's really tight in there.
1605898900888.png
 
So, a fellow Havenite reached out for a pair of the horn for his WE757A cabinets. His cabs already have the WE728B minus the horns. Had to model up the WE757A cabinets for the virtual fit-check. Also, remodeled the horn. Increased the wall thickness to 0.25". Interior vanes start near the throat at 0.050" becoming 0.100" thick at the mouth. Broke the horn up into 6 pieces with tongue and groove features for glueing. The pieces were also welded with a 3D pen to increase strength.

View attachment 29565View attachment 29566View attachment 29567

View attachment 29569View attachment 29570

It's really tight in there.
View attachment 29568
This is a great project! What driver is the buyer going to use in the horns?
 
So, a fellow Havenite reached out for a pair of the horn for his WE757A cabinets. His cabs already have the WE728B minus the horns. Had to model up the WE757A cabinets for the virtual fit-check. Also, remodeled the horn. Increased the wall thickness to 0.25". Interior vanes start near the throat at 0.050" becoming 0.100" thick at the mouth. Broke the horn up into 6 pieces with tongue and groove features for glueing. The pieces were also welded with a 3D pen to increase strength.

View attachment 29565View attachment 29566View attachment 29567

View attachment 29569View attachment 29570

It's really tight in there.
View attachment 29568
Really smart solution there - I'm sure that extra thickness will help you avoid having to support the compression driver separately.
 

billfort

Administrator
Staff member
Wow! Your projects never cease to amaze me Tsingtao - it's like your mad DIY skills and the best of modern technology have given you a shot at the very best of audio's past. Must be fun to 'hear' treasured audio antiques to get a real glimpse of what they could (or couldn't!) do.

So very cool.
 
What driver is the buyer going to use in the horns?
Sorry, will have to let the owner chime in.

having to support the compression driver separately.
Hanging the driver off the horn is not recommended. The driver weighs a little over 7 lbs. PETG is strong enough for a static load. But, any plastic will deform over time with that much weight.

Breaking the horn in to smaller pieces has the added benefit of making the horn modular. Below is a straight throat version for the standard 1" screw on driver by swapping out the throat piece.
IMG_5477.jpg
 
Last edited:
Top