DIY radial wood horn - a kind of how to

1. Calculate the wanted profile with any horn calculator, e.g.: http://melhuish.org/audio/tractrixcalc.html
2. Paste the numbers into the attached spreadsheet.
   
   If the numbers do not look reasonable, you'll have to go back and resize the horn. Use the offset adjustment to get the column "Full horn height" close to the driver diameter.
   
   PS: The worksheet needs the geofunc.xla to work.
3. Draw a profile. Look at the profile.jpg for an example.
   
   Draw a line in the center. Mark offset and all the distance measurements. Draw lines 90 degrees out from the center line, at all distances. Draw the line: "Height / 2" to each side.
   
   Finish the drawing, like the example, drawing a rectangle around everything, and connecting the profile like an arc.
4. Cut the drawing along the rectangle. Then again cut the drawing in 3 by following the arc. You will then get one horn profile and two block profiles. This is enough for one horn.
5. Glue the 2 block profiles on the side of 2 wood blocks.
6. You'll need a jig for your router when routing the blocks. Ideas: http://audioheritage.org/vbulletin/s...ht=preparation
   
   or at the attached Fres1.jpg.
   
   The jig must support a rotating horizontal movement without vertical movement.
   
   Route away everything but the block profile.
7. Glue the horn profile to a cardboard or a thin piece of wood. Make at least two horn profiles. Cut the board along the edges of the horn profile. This will be used to get the right distance between the two routed blocks.
8. Add sides with glue and / or screws / taps.
9. Mounting plates for the driver should be made as thin as possible.