1200Hz Smith horns for 1" driver

[John W]

That is a great idea. This was the most tedious aspect of the project. Make sure you clamp them down good, especially on the second side. Being so thin they tend to shift off perpendicular.
Is the radius you mentioned for the 1200hz, or the full size 2397? I think the 1200hz vanes are 6.15 inches rather than 8.

[Mr. Widget]

The 8 inch vane has a beautiful 24 inch radius on it.

That is so funny... I never thought to check. I just checked my original CAD It is indeed a perfect radius. 24" will give you an error of about .09" at the tips. You should use a 25.25" radius.

Since I plotted these from cross referencing several sources and machined them with my CNC router, I never bothered to check. Thanks for pointing that out.

These numbers are for the full sized 2397.

Widget

[bbrown]

Thanks Widget. The 24 inch seemed to line up on he drawing pretty well, but there was obviously some play with the pixels. I'll just change my notes that it should be 25.25 inches.

It will be during the summer before I get to any of this, but I've been gathering notes long enough.

Bruce

[Woody Banks]

Widget
I discovered the same thing by accident with the radius while I was constructing the vane gig. The first pair was without a gig came out alright but not perfect. I used Jotoba because it was what I had in the shop. I will start the full size pair this next week using 6/4 Jotaba. Thanks for all the input.
Woody

[Michael Smith]

Here are some pics of my prototype Johnny inspired Smith horns.
I have used 32mm MDF top and bottom plates with both sides of the vanes rebated to ensure a nice snug fit (probably alittle anile ) but what the F.
It goes together like a dream.
I will finish these then give them a test drive and report.
My intention is to fashion them out of sequoia and french polish them (any problems with my timber choice? ) if so feedback would be appreciated.
Regards to all
Michael

[yggdrasil]

Hi again. Just back from 2 weeks of defrosting in Crete, Greece.


Woody, great looking. Beautiful work.

Michael, great work. Nice work with the router.

I must admit getting more than a bit envious at your abilities and tools.

Bruce / Widget: I have done some calculations on the 6.15" vane "radius". Using the CAD-drawing and measuring radius would be 48.6cm / 19.13". I tried using the worksheet, and calculate the ratio, giving 49.3cm / 19.41".

Rjig = 3.156 * vaneLength

Widget - are there any differences between JBL and Westlake vanes?

I would think that the formula for Rjig would be sufficiently accurate for practical purposes.

[Mr. Widget]

Widget - are there any differences between JBL and Westlake vanes?

Nope.

This is how I mount the ribs. I too have rounded corners in the rabbets, but then I notch the ribs. This way they are still sharp. I don't have a photo of just a rib, so this is a CAD drawing of one.

Widget

[bbrown]

Michael,
Do your top and bottom plates just have a rounded front edge, instead of tapering a bit like Widget's drawings? Sure would be easier to make.

Bruce

[Michael Smith]

Bruce I did it that way because I thought that 32mm would look crappy,How thick is your base you pictured Mr Widget?
As this is the prototype I could and probably would change it if I can get my hands on a bigger chunk of timber.

Michael

[Mr. Widget]

How thick is your base you pictured Mr Widget?

I started off with 8/4" rough lumber. I planed it down to 1.75" for the Westlake clones and 1.625" for the JBL 2397 clones... in the case of the 2397s I picked that thickness as it looked the nicest to me.

Widget

[Ken Pachkowsky]

Title says it all.

[aust-ted]

Title says it all.

Great work

Regards
Ted

[John]

One thing to keep in mind is that on both the JBL and Westlake horns the dividing vanes are razer sharp at both ends???

[MatthiasA]

i made a bigger CAD-drawing than the one on the first Side
if anybody want it its a DXF - file
greetings Matthias

[MatthiasA]

today i made the Horn :-)
very good sound with a 2425H driver!

greetings Matthias