**Please Note: All tools for non commercial use only!!**

### Tapped Horn Design Utility

Tapped Horn Design Utility v1.1, 30KB

I used this spreadsheet recently to design some tapped horns. Basically it helps you to calculate the parameters to be entered into the wonderful Hornresp program by David J McBean. Updated version with estimation of double folded tapped horns (as for example the mini Tangband tapped horn).

### Tractrix Horn Calculator

Tractrix Horn Calculator v1.3a, 321KMB

Tractrix Horn Calculator v1.4b ⇐ Beta Version! with some new features, 372KB

Here is a (at least for me) very helpful tool to calculate and design straight round and rectangular Tractrix horns as well as Hypex Horns. A “filter section” is currently under construction.

It’s throat calculation is based on the “Show Horn” article and the tractrix formula is from the Edgar Midrange Horn article. Both articles written by Dr. Bruce Edgar for the “Speaker Builder Magazine” (articles see below).

I included some helpful functions to easily create script files to draw the Tractrix curves in AutoCAD (TM). You just have to copy a column to a test file with the extension *.scr. Then execute the so called script file in AutoCAD. Be sure to switch off “ortho” and “osnap” before. This sometimes causes strange results.

If you have problems understanding what I did or what this spreadsheet is able to do for you don’t hesitate to contact me.

### Tractrix for Akabak Calculator

Tractrix for Akabak, Rev. E, ZIP file 200KB

This is an alternative version of the Tractrix calculation sheet I recently created. The idea of this tool was initiated by Kees of diyaudio. He asked me if the table can be modified so that it creates output for Akabak (as it is required for the Trynergy project – a full range Tractrix Synergy). It allows to calculate Tractrix profiles for both rectangular and round horns while output is generated which can be cut and paste into Akabak for simulation. For the Tractrix calculation I used some VBA code (thanks to WGH of diyaudio) which I modified a little bit.

Left hand side:

The “old” calculation scheme, where the distance throat to mouth is divided in a predefined number of pieces (here 100), and for each piece the corresponding point on the length axis of the horn is calculated. The resulting duct pieces for Akabak are “thicker” at the throat and “thinner” at the mouth.

Right hand side:

The “new” calculation scheme. You can define a step width, which defines the increments on the length axis of the horn for the calculation of the corresponding radius. The resulting duct pieces for Akabak are of constant thickness except for the last one at the mouth (which is the rest of the integer division of horn length / step-width).

Due to the VBA code you have to activate macros inside Excel.

### Tractrix for multi sided Traxtrix horns with polygonal cross section

Polygonal Tractrix, Rev. 5, ZIP file 1.2MB

This version of the Tractrix calculation sheet serves to design multi sided (petal) horns. It was specifficly created to support a public art project by Marek Walczak & Wes Heiss, where in a park in the Clayton & Cole neighborhoods, Denver, two steel “megaphones” will soon be installed as permanent sculptures.

Due to the VBA code you have to activate macros inside Excel.