As many of you know, Manfred Schroeder has significantly helped change the science of acoustics. His research in number theory, is wonderfully described in two informative volumes Fractals, Chaos, Power Laws: Minutes from an Infinite Paradise, Manfred R. Schroeder, 1992 and Number Theory in Science and Communication, Manfred R. Schroeder, 1997. RPG's initial sound diffusion products utilized number theory sequences and these products have contributed to the success of thousands of facilities.

Over the past 16 years we have learned how to design, predict, measure, evaluate, optimize and soon standardize the performance of sound diffusing surfaces. This research has provided the tools to develop a new era in sound diffusion design based on our proprietary Shape Optimization software. RPG will be gradually phasing out the older number theory designs and introducing a new line of diffusors called Optiffusors. These products will offer a significantly higher level of performance, so stay tuned.

RPG to Distribute for Lake Technology
Lake Technology is a high technology company based in Sydney, Australia. Lake has more than 40 patents and patent applications pending in digital signal processing (DSP), 1-bit signal processing, digital communications technology, video games, internet media and related product areas. The company commercializes its innovations via proprietary products and licensing and has one of the world's leading research and development teams in audio and DSP at its Sydney research laboratories. The company originated the technology behind 'Dolby Headphone' a system for providing cinema-quality surround sound over ordinary headphones.

RPG is proud to announce its appointment by Lake Technology as a distributor of its line of convolution hardware to the architectural acoustics industry. The range includes the CP4 and Huron convolution platforms. The CP4 is an affordable real time convolver with zero latency, meaning that once you have downloaded an experimental impulse response or a SIM file from CATT Acoustics you can instantly audition the room with any sound source in real time, for as long as you like. The Huron system is the big brother of the CP4, allowing more complex interactive audio simulations including walk-troughs.

"The CP4 and Huron systems are powerful tools which are seeing an increasing use in the architectural market. We are very delighted to have RPG as a distributor in the US, they have an excellent global reputation", said Patrick Flanagan, Sales Manager for the Huron and CP4. Dr. Peter D'Antonio, President of RPG, indicated that "RPG is significantly expanding its Digital Acoustical Palette and is very excited to add Lake Technology to its growing list of digital products. The Lake technology is a natural extension of our collaboration with CATT Acoustics and offers the architectural acoustics community complete auralization capability."

International Symposium on Surface Diffusion in Room Acoustics
Liverpool, Sunday, April 16, 2000
Dr. Peter D'Antonio will be presenting a paper entitled the "Evolution of the Uniform Diffusion Coefficient". The main theme of the International Symposium on Surface Diffusion in Room Acoustics will center around the standardization efforts of the AES SC-04-02 and the ISO working groups to define a diffusion and scattering coefficient. The preliminary programme will start with two presentations, one from the ISO WG chairman Jens Holger Rindel and one from the AES Sub-committee chairman Peter D'Antonio, describing the findings of the working groups. The technical details of the definitions and measurement of the scattering coefficient and diffusion coefficient will then be described in presentations by Eckard Mommertz and by Trevor Cox. The programme will also include a number of presentations on the application of diffusers in room acoustics and the modelling of surface diffusion in computer models. A discussion session is scheduled at the end of the presentations to allow delegates to participate in the discussion and give feedback. For more information and a registration form, download the 217K PDF file.

Concert Hall Acoustics: Art and Science
The Royal Festival Hall, South Bank Centre, London, UK
January 28 - February 29, 2000


The free multimedia exhibition is intended to show how science and engineering have influenced the design of concert halls. The science of room acoustics has built up over the last hundred years. Before this, good concert halls were built by a process of trial and error. The features of the best halls were copied, sometimes successfully, sometimes not. It is often assumed that in the past we had some great talent to build good concert halls, and now we have forgotten the know-how, but this is the stuff of myth and legend. Today, with the knowledge and understanding gained through acoustics research, we can build concert halls knowing that the chance of building a good, or even a great hall, is much better. RPG is proud to have taken part in this educational and informative exhibit. Visit online at www.hallacoustics.co.uk.

Diffuse Seminars
RPG is now offering regular educational seminars for acousticians, sound contractors, home theater system integrators, architects, and other specifying consultants to apprise the industry of our research, new products, application assistance, and an introduction to RPG's new Room Optimizer™, Shape Optimizer, and CATT Acoustics software. The press is also welcome.

The response to these educational seminars has been very enthusiastic and current seminar dates are available. If you are interested in attending, please e-mail to info@rpginc.com, contact your local rep or call Jeff Angel at 301-249-0044.

EASE v2 loudspeaker export-file (.EXP) to CATT-SD1 import text-file converter
CATT is working towards receiving first-hand data from most manufacturers but until a complete set is available loudspeaker exported from EASE v2 can be converted to CATT SD1 format. This can either be done by those that already have access to EASE libraries or if the open format export files (.EXP) are requested from each manufacturer. Unfortunately, the AES did not establish an open file format standard so the EASE v2 export-format has to be used.

SIAP in North America
Visit the RPG Acoustics Library for a new PDF paper by SIAP on Design Criteria for Acoustic Enhancement Systems, by Ben Kok and Wim Prinssen of Systems for Improved Acoustic Performance, Uden, The Netherlands presented last summer at the 6th ICSV in Denmark.

Abstract
Acoustic Enhancement Systems have evolved significantly — both technically and by acceptance — over the past decade. Numerous publications are available covering the design philosophy and successful installations. For people not directly involved in the implementation of these systems, it often is difficult to determine if a proposed design will perform to expectation in their situation. They are often confronted with large numbers of loudspeakers and microphones at — generally — undesirable places, but have no way of judging if the proposed configuration is the optimum, or that modifications are possible without negative influence to the end result. This paper will describe basic design criteria for Acoustic Enhancement Systems like loudspeaker density, microphone positions, number of required processor in- and outputs, etc. These criteria can act as a tool to evaluate proposed designs, as well as a way to estimate the required provisions to be included in planning such an installation. By presenting these criteria we hope to give our contribution to demystifying the "magic art" of designing Acoustic Enhancement Systems and thereby further increasing their acceptance as a viable tool in modern acoustic design practice.

RPG Factory Summer Shutdown
This year RPG will close its production facility during the week of August 14-20th. We announce this early so that all of our specifiers, clients and representatives can plan their orders and deliveries accordingly.