Posted by Wayne Parham on April 21, 2003 at 10:35:18

In Reply to: Re: Pi design and wooden horns(Edgar & Martinelli) posted by Tom Brennan on April 21, 2003 at 02:50:43:

I agree with you about Altec horns in many ways. Measurements show them to be extremely flat on-axis, and they sound good too. They are physically large, so they can be crossed over low. And they distribute energy with greater dispersion side-to-side, which keeps from wasting energy on the ceiling or the floor. They're a great horn for a large two-way loudspeaker, in my opinion.

The only problem is their collapsing directivity. I don't mind it so much in the vertical plane, but would prefer constant directivity in the horizontal plane. An interesting read is the AES paper called "Improvements in Monitor Loudspeaker Systems," written by David Smith, Don Keele and John Eargle. The paper talks about this kind of design using a CD horn, and discusses the crossover region, directivity issues and other important features of a large two-way loudspeaker.