1200Hz Smith horns for 1" driver

[yggdrasil]

From other posts on this forum I have gotten the idea that it is possible to improve on the H91.

So I have found some info on the smith-horns, and with help from Widget I tried to resize them to 1200Hz.

I have also made a prototype from MDF, thinking that I would have to do this many times.

Here are the construction drawings used.

[yggdrasil]

Some pictures of horns and adaptors.

[yggdrasil]

Have not been able to try them much. Family you know...


First impression is H91 - goodbye.

It will be a hell of a job to redo the baffle...

[Ian Mackenzie]

Nice work.

Very tempting, how did you craft the curves..with a router?

About the baffles..been there done that...LOL....messy and it tends to be one way trip. I have to say the 2397s were fun but tended to take over at times according to my neighbours. Used correctly however they are most transparent, open and non sounding horn.

Don't panic, I am not going to hack into the 4345's (yet) next on the list is is quad amping and 275nd drivers.

I think an array of 2397 style horns would be very interesting, say 250-800, 800-4000, 4000-daylight.

Ian

[Mr. Widget]

Very nice work! I guess if you like them as much as hoped you may want to try a crack at them in a nicer wood. I may have to bang out a set and get some measurements of them....

Widget

[Robh3606]

Those look nice!!!

Rob

[jandregg]

Very nice. I have been thinking about a similar project, although far into the future. Please post your progress. And thank you for sharing.


John

[yggdrasil]

BEAUTIFUL!!!!

Have been listening a little now and then. I can't find words to describe these beauties.

Won't have time to do measuring until sunday. My wife is 40 and having a major celebration on saturday. Any more speaker work now and I'm dead... Have you ever got the feeling - my wife don't understand me?

[yggdrasil]

Today I finally got the time to do some testing.


Testing equipment is far from adequate. Will have to get a decent mic and software. Probably also better hardware for signal generation.

Here's the results with phenolic diaphragm.

[yggdrasil]

And here's the result with the titanium diaphragm (d15r2425).

[yggdrasil]

I run this test on my laptop with a demo-version of WINAIRDD.

The titanium dia's are rolling off earlier than the phenolics?

The results were checked on a Klark Teknik real time analyzer with a test microphone, showing the same results, but actually they were readable.

Phenolics -3 to 0 db from 800 to 8000.
Titaniums -4 to +3 db from 800 to 8000. (-5db from 400...).

Tried the signal generator on another software, but with that software the resulting curve was only flat from 1.6K to 4K measuring on the Klark Teknik. Did not have the cables etc. to use the Klark Teknik as a signal source.

[DR Carlson]

I've been going over the varous posts concerning the Smith horn, and I'm interested in building some. The problem I am coming up against, is getting enough info to design then build one properly.
I have down loaded the 1951 artcle from Audio Engeering written by Bob Smith, but it is not the best copy, on page 17 figure 5 there seems to be a triangler plug right at the mouth of the horn spaced 5/16" in front of the back plate. Can anyone enlighten me.
Also is it possible for anyone who has design/construction info on these, Perhaps other magazine articules etc to be able and send them to me. I can take most formates including DWG DXF, JPG etc.

Thanks Dave C.

[yggdrasil]

I tried redrawing the original Bob Smith drawing using his calculations, drawing and a CAD-program. There were some errors in my calculations. I got quite close but...


However - the triangular drawing in the horn throat shows the origo (circle centre) and the angles of the 5 vanes / islands.

Anyway the drawings presented in this thread are built on JBL's work on the 2397 horn. I have not tried to make any horn following Bob Smith's design 100%.