As the chief developer of CARA (Computer Aided Room Acoustics) I want to clarify
the mathematics implemented in CARA.

Dr. Geddes states:
"CARA is a ray tracing program. It will not be able to do the LF modal study. Ray tracing
methods do not retain phase and as such do not correctly predict standing waves.
They only work above the modal region, not below it. "

CARA is not a ray tracing program! If CARA was a ray tracing program then
Dr Geddes would be right. But CARA is based on a model using sound source images
and therefore calculates the total sound field (direct and diffuse) with complex
numbers (magnitude and phase).

I ask Dr. Geddes and all others interested in this subject to try the "CARA
Walkthrough" on www.cara.de .
CARA correctly predicts the modal structure of the room sound fields. CARA
focuses on the room acoustics of small rooms and we pay very particular
attention to correctly calculating the room modes because these are relevant for
all frequencies up to several hundred Hz.

Best Regards,

Dr. U. Franz Thomanek
ELAC Technische Software GmbH
Rendsburger Landstr. 215
D- 24113 KIEL
Deutschland/Germany

Tel +49 (0)431 680779
Fax +49 (0)431 682101
E-Mail tho@cara.de
Internet www.cara.de