Thursday, August 21, 2008

"An Almost Round Horn"

Or, as the weblink is called in German, Ein fast rundes Horn (article in English, though). This is an oldie, it must have been pre-2000 when I read first read this. There is some really good practical stuff in here. It leads to a highly specific way of building a horn, that I never copied exactly nor directly. At the same time, every step and procedure gives lots of ideas for my own DIY-projects. I think you should read it and at the very least appreciate creative engineering. I bet some readers will get some ideas for their own projects.

The basic idea behind the article is that a round horn is good and a square horn is bad. But to make round horns requires a lot of effort and materials (moulds or lathes). Curved panel horns on the other hand are somewhat easier to make with more conventional home tools, like saws and the like. The further away your design is from square and the closer it gets to round, the better it is. The solution that this artical offers, is to use more than four curved panels.

Basically, you are making your own version of the classic petal horns of early grammophones. Of course, by choosing your own design parameters and materials/drivers, it will turn out rather differently in terms of looks and sound.

The reason I get back to this old article, is that I am building a set of petal horns myself, which I hope to showcase here occasionally over the next few months. Some aspects of my design and building processes are interesting as well. I will show and illustrate them here.

We are back and we are moving forward!


Dresden said...

An interesting approach to building an 'almost round' horn.

I'm in the process of building a prototype horn, except I'll be using clay atop turning platform to create the contour. Assuming all of my calculations are correct, the prototype should have a usable cut-off frequency of 400Hz.

I would like to know if anyone has a calculator for conical horns. I've looked around but have only found calculators for Tractrix and Exponential horns. A calculator for conical horns would help, given that the flare I'm using is close to that of a conical horn (although it does espand).

If anyone has such a calculator (spreadsheet), please let me know.

Ivo Tichelaar said...

Yes, I want to know, too... :)