RPG president, Dr. Peter D'Antonio, has expanded the company's mission to continually expand the acoustical palette with innovative AcousticTools™ for the architectural acoustics market. "Over the past 16 years we have been privileged to introduce a wide range of new technologies to the architectural acoustics market. Today we are further expanding our product range to include optimization software and services, auralization software and hardware, electronic enhancement systems and now a new decorative wooden absorptive panel system with selectable absorption. It is my belief that a full-service, all-acoustic team, with well-trained personnel will best serve the needs of today's acousticians, by providing them with all of the tools and services they need. Therefore, while you may have thought of RPG as an innovative diffusor manufacturer, we would invite you to think of RPG for all of your acoustic needs."

RPG Announces Topakustik And Topperfo Absorptive Wood System
In a continuing effort to broaden the acoustical palette, RPG now announces a major new product line of decorative absorptive wood systems.

The product line consists of TOPAKUSTIK, an attractive and durable perforated wooden panel or plank system with a parallel-grooved facia and TOPPERFO, a wooden panel with a regular array of holes ranging from 1 mm to 8 mm.

Topakustiks is available in a mid-high (M) and also a low-mid frequency (T) system. This allows two different absorption characteristics for a wide range of absorption options with the same visual appearance.

The mid-high M system achieves absorption over a wide range of frequencies by utilizing a range of hold diameters, spacings and air cavity depths. A typical 5/3M system consists of a 5 mm wide flat reflective area and a 3 mm wide slot. The panel is perforated with a 12 mm diameter hole with an open area of 12%.

The low-mid T system utilized dual diameter holes. The same 5/3T system consists of a 5 mm wide reflective section, a 3 mm wide slot, a 3 mm hole at the face (for pleasing appearance), expanding into a 12 mm hole through the rest of the panel. Thus the 5/3T system offers open areas of 3 and 31%.

The TOPPERFO system is also available in a mid-high frequency M system and a low-mid T system. The M system offers a single diameter hole ranging in diameter from 3 to 8 mm on 16 mm centers. The 16/16/6 M system consists of 6 mm holes on 16 mm centers with a percent open area of 11%. The 16/16/12-3 T system consists of dual diameter holes of 3 mm at the face and 12 mm at the rear offering 2.8 and 44.1% open area.

The core is fire-rated MDF or non-combustible gypsum. Standard veneers are offered and special veneers are available on order. Topakustik is available in panels up to 1200 mm and planks of 128 mm width. Various lenghts are available. Topperfo is available in a wide variety of panel sizes. Standard thickness is 17 mm with 19 mm thicknesses available for extra heavy duty applications, like gymnasiums.

Applied Acoustics Special Edition Vol. 60, No. 2 (June 2000)
The Applied Acoustics journal has recently published a special issue on Surface Diffusion in Room Acoustics guest edited by Y.W. Lam, Director of the Acoustics Research Centre at the University of Salford. The editorial by Lam describes surface diffusion and mentions the current AES and ISO standards working groups.

The first paper "Diffusor application in rooms" is a review paper by Peter D'Antonio and Trevor J. Cox. This paper discusses the application of diffusors in music production rooms, such as performance facilities, and music reproduction rooms, such as recording studios. The next paper by James A.S. Angus, entitled "Using grating modulation to achieve wideband large area diffusers" discusses the application of modulation techniques to mitigate periodicity effects that accompany wide area concatenated coverage.

The next paper "Acoustic phase gratings for reduced specular reflection" by Trevor J. Cox and Peter D'Antonio describes the use of optimization techniques to create a better broadband notch diffusor with specular suppression. Michael Vorlander and Eckard Mommertz' paper on the "Definition and measurement of random-incidence scattering coefficients" describes the definition and two methods for measuring scattering coefficients of rough surfaces. This is followed by a technical note by Eckard Mommertz on the "Determination of scattering coefficients from the reflection directivity of architectural surfaces".

Torbjorn Johansson and Mendel Kleiner describe a method for the "Prediction of the scattering properties of surfaces by laser scanning of height profile". Geometrical data is obtained by an optical laser scanning technique, now available commercially by several vendors. The next paper by K. Fujiwara, K. Nakai and H. Torihara entiled "Visualization of the sound field around a Schroeder diffuser" experimentally accomplishes this using fine cork powder in a Kundt's tube.

M.J. Howarth and Y.W. Lam's paper on "An assessment of the accuracy of a hybrid room acoustics model with surface diffusion facility" describes the need to refine the modeling of surface reflections and possibly describe the directivity of non-specular reflections. The last paper by Fergus R. Fricke on "Visual assessments of the surface diffusion properties of concert halls" attempts to link the acoustic quality of a hall with its surface diffusivity index using a neural network.

Sweetwater U Presentation
As many of you know Sweetwater is one of the world's leading catalogs for pro audio gear. What you may not know is that they hold 1 ½ hour long classes in the evening from 6 to 7:30 to train their sales force. Try getting your employees to work evenings! During the class we reviewed the sources of Acoustical Distortion and ways to minimize using RPG products. The control room at Sweetwater Sound features RPG's ProFoam™ on side wall, ceiling, and above. Skyline® diffusors are mounted on the rear wall above the couch.

Spatial Audio Special Interest Group
This message is an invite to join the Spatial Audio Special Interest Group. The purpose of this list is to act as a forum for discussing all aspects of spatial audio; concepts and applications, hardware and software, tools and techniques. It is hoped that the group will involve people with many different backgrounds such as from the domains of Auditory Neuroscience, Acoustics, Computer Science, Electronic Engineering, Art and Architecture, Ergonomics, Psychology, Virtual Environment Design etc.

Topics for discussion will include room acoustic prediction and auralization, spatialization, virtual reality simulation, and many others. This is a new list and we expect that it will take some time to get running properly.

If you would like to subscribe to this list then send a message to the following address: Majordomo@leeds.ac.uk. In the first line of your message box type:subscribe sa-sig. Please do not type anything else into the message box (and do not include your signature if at all possible as the mailbase client will flag errors). Once your subscription request has been processed, you can send messages to: sa-sig@leeds.ac.uk. Both subscription and unsubscription are controlled by the list administrator and requests may take some time to process. If you have not received any acknowledgement from the mailbase regarding your subscription then please be patient and allow at least 1 week before re-sending your request.

Upon acceptance, each list member will be required to submit a short description of their specialist area and interest in the group. This is a mere academic exercise so that we can have an idea as to the diverse range of interests that our members have. We hope that you all enjoy using this list and find it to be very useful. Peter Rutherford, List Administrator

Syn-Aud-Con
Syn-Aud-Con provides training for the audio industry. Over 10,000 people have attended their seminars in their 25-year history. Their seminars and workshops are held in major cities worldwide. The schedule is on listed on their Web site. Members receive a quarterly Newsletter and Tech Topic, as well as access to the Syn-Aud-Con email listserv. Browse their on-line catalog for education materials. Please contact them for more information.

As many of the acousticians and sound contractors in the architectural acoustics industry know, Syn-Aud-Con played a significant role in the growth of RPG in its fledgling years. The enthusiastic support of Don and Carolyn Davis will always be appreciated. RPG supports the outstanding job Syn-Aud-Con has done over the years and is very pleased at the way Pat and Brenda Brown have carried on the tradition.

Over the past four years, since Dr. D'Antonio retired from his research position with the Naval Research Laboratory for the Structure of Matter, RPG has focused on expanding its product line to include digital and anologue surface treatment products, optimization software, auralization software/hardware and electronic architecture. This new expanded product line is called the Complete Digital Acoustical Palette. To inform the sound contracting market of this wide range of products and to share its research, RPG has re-established a collaboration with Syn-Aud-Con and will be participating in the various trade shows that target this market.

In the next issue of the Syn-Aud-Con Newsletter, Dr. Peter D'Antonio will contribute a regular column on diffusion standards and other topics. RPG's new Room Optimizer software will be discussed in an article on room modes. RPG will also be collaborating with Pat Brown on various acoustical research experiments and measurements that will be featured in the Newsletter..

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."

Diffuse Seminars
RPG is now offering regular educational Diffuse 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. The seminar dates for 2000 are now 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.

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.