BAM,
I just read your first post in this thread, and saw your request for modelling software.
Do a search in google for Hornresp by David McBean a really excellent and powerful free program. I wouldn't even think about anything as unweildy as Mathcad until you want something really odd or specific, apart from the standard exp/hypex, trax and conics.
AJHorn is also available but I think it's about 100Euro. Sorry, can't provide URLs as hy HDD died recently and I'm on a borrowed lappie.
Equations and other sundry horn info available at
www.melhuish.org . Go to Single Driver site, and click on horns. There are also some basic calculators online, as well as a number of projects to look at. Ketil Parow's Big Fun and AllFun Lowther horn articles linked from the site also contain a ton of useful info for budding horn designers.
I also have access to a spreadsheet to do some of the calcs for the actual dimensions of the flares, but I can't send it at the moment. Ping me with a PM at the end of the week and remind me.
Optimum throat size (from Keele) is
St = 0.8 x Fs x Qes x Vas
Fs= driver resonance
Vas = cu ft
St = sq in
Then set the flare type to hypex, m between 0.4 and 0.8, although subbing in a short conic section in the throat can yeild big dividends in distortion performance, with little LF loss compared to a straight hypex. Don't use a trax or conic for bass esp for PA. I deally the Fs of your drivers should be near the flare rate of the horn, and you should be looking for around 40Hz to cover the bottom of an electric bass' range.
