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DIY ~3kHz conical horns

audiozaz

audiozaz

rtfm!? - tl;dr
I got the idea of building small horns by layering 0.5" BB ply and drilling 1", 2", 3" and 4" holes, then beveling the edges 45° to have a smooth wall, thus creating a 90° HF horn. Hornresp showed me it should not be too awful. Some "scrap" pieces of BB and a few hours of work have produced the following:

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I will try P.Audio BMD-440 1" exit compression drivers on these, on top of my Karlsons. Still awaiting driver delivery.

az
 
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Thanks guys!

This is my first semi-serious foray into DIY horns. I had only stuck together some hardboard with hot glue for a midrange horn on Fostex FF125K for kicks last year or something. I don't know if a 90° conical horn for HF is even a good idea, but Hornresp did not discourage me at least and there's not too much investment here, so I gave it a go. Hope it works at least decently, I'll be happy.

az
 
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I wonder how a nice soft dome would work on one of these?

Did you router it while they were all together or separately?
 
I've been trying to download that dang Hornresp. program for the longest time and my efforts have all been unsuccessful.

How did you snag it?


RC
 
ejfud said:
I wonder how a nice soft dome would work on one of these?

Did you router it while they were all together or separately?
Click to expand...

All 4 layers routed separately. Finding the exact depth for the 45° bevel bit was the trick. I routed over guide holes of the same diameter for the bearing to roll on something. The wood is actually more like 7/16" so fit was not perfect, but good enough for sanding to smooth out nicely.

doucanoe said:
I've been trying to download that dang Hornresp. program for the longest time and my efforts have all been unsuccessful.

How did you snag it?


RC
Click to expand...

You run a PC? I think it won't run on Mac.

http://www.hornresp.net.ms/ should do it. If there's trouble, I can see about sending you the file, should not be very big. It's a good program to simulate more than just horns too.

az
 
djnagle said:
Very Nice AZ!!! Will you be making measurements? Love to see how they plot.
Click to expand...

Yes, I'll attempt this. :) My basic setup for response measurement should give a fair enough idea. It will be fun to compare it versus the Transylvania Tubes and see if it matches the Karlson wavefront. IMO conical has a good enough chance.

Here is the Hornresp predicted transfer function for the horn:

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az
 
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Drivers in place:

No flash:

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Flash:

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These P.Audio BMD-440 seem to be well-made and I got a sweet deal on them too.

az
 
Those look very nice.:yes: Did you use a lathe?

edit: beveled router bit-
 
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Awesome job.

For those without routering skills like myself, Look up making a bowl on a table saw.
 
jsixis said:
Awesome job.

For those without routering skills like myself, Look up making a bowl on a table saw.
Click to expand...

Thanks!

Neat trick for the table saw bowl. As for router skills, I'm pretty much a noob on this tool; work safe and taking your time is the way to go IMO. The router only got me a rough shape anyway, there was a lot more work done in the hand sanding stage.

az
 
I added an ''oblate spheroid'' throat section for better driver loading and a smoother transition to a spherical wavefront. That might sound fancy, but there's no real math behind the profile, just some sanding done by eye. :)

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I had quickly listened to them on top of Karlson and they were good IMO, although they did not blend as well as the K-Tube. The above fix may help with that, hopefully.

az
 
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