The SW tools provided on this page are free and offered on an as-is basis. However, if you feel these small programs are useful and want to give something back, then please consider donating. There's a Donate button at the bottom of the page. The money will help support my horn loudspeaker research project, which has very little funding from the university.
The Modal Propagation Method (MPM) Toolbox for Matlab is now available. It enables you to simulate axisymmetric horns terminated in an infinite baffle, with accuracy approaching BEM, but with higher speed. See my reports and the blog entry on modes in horns for details.
It seems like the Toolbox does not work with Octave. I have only done brief tests, but so far it looks like the problem is the numerical integration routines used in the calculation of the modal radiation impedance. If you develop a solution for this, please contact me, and I'll be happy to add the Octave file to the Toolbox (with due credits, of course). I have plans to include a pre-computed table of the radiation impedance to speed up calculations, and this would probably remove this obstacle.
Please also contact me with bug reports.
Latest version is 1.1. Changelog:
Added units for the input parameters.
Corrected numbering of figures in MPM_Horndemo1 and MPM_Horndemo2.
Added link to placeFigures script.
Below is an illustration of the results produced by the MPM Toolbox. This is from the MPM_Horndemo1 file, using 6 modes and 100 frequencies.