ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

1pEA3. Recent advances in computer-aided design of loudspeakers.

Vance Dickason

Vance Dickason Consulting, 333 S. State St., Ste. 152, Lake Oswego, OR 97035

Although successful CAE software that allows the accurate simulation and development of loudspeaker enclosures and crossover networks has been available for professional design work for several years, a number of loudspeaker industry practitioners still persist in using traditional methods of ``cut and try.'' This presentation outlines a computer-aided loudspeaker development case study of a commercial three-way loudspeaker using a vented enclosure and a crossover network that incorporated fourth-order acoustic slopes. Measurement of the resulting prototype showed close agreement, within 0.5--1 dB, with the computer simulation. Time required for the development of the fairly complex crossover network determined for this loudspeaker was less than 1.5 h, substantially less than what is generally expected of ``cut and try'' methods. Key to the resulting accuracy using this type of computer software is the correct portrayal of interdriver time delay and driver phase. Driver phase for this project was derived from the driver magnitude using a highly sophisticated phase calculation methodology, as opposed to being directly measured with a two-port analyzer. Other criteria responsible for the success of the loudspeaker modeling portrayed in this case study are the ability to predetermine the group delay performance of the enclosure design, and the ability to examine crossover network transfer function during the design process.