NKB Bank Lobby, Stans, Switzerland
Topakustiks and Topperfo comprise the largest and most versatile acoustical wood system in the world. We present some photos to give our readership an example of the wide range of applications that are possible with this aesthetic acoustic system. From planning to installation, RPG supports you with extensive services and selection. To help you make the correct choice, we provide product samples and absorption coefficients for all of the Topakustik and Topperfo family of products. For planning purposes all of this information is provided on the web for access when you need it. This extensive system of Topakustiks and Topperfo products offer harmony in variation.

Imax Theater, Berlin, Germany Custom circular Topperfo ceiling provides a beautiful accent in the lobby of the Imax theater, integrating lighting and acoustics.

Red Cross Cafeteria, Bern, Switzerland Attractive Topakustiks acoustical ceiling integrates lighting and noise control with the structural metal trusses.

RSI Broadcast Studio, Lugano, Switzerland In this broadcast we integrate QRD 734s with Topperfo to wall panels for a powerful and aesthetic acoustical design.

Spa, Sarrow, Germany The Topperfo wall and ceiling panels in the lobby of this spa offer a warm, aesthetic and inviting appearance.

"AES information document for room acoustics and sound reinforcement systems- Characterization and measurement of surface scattering uniformity ", J. Audio Eng. Soc., Vol. 49, No. 3 (March 2001)
As Chair of SC-04-02 I wanted to thank the working group and especially my Vice Chair Dr. Trevor Cox for such an outstanding job in helping to develop the information document. After 16 years of sometimes-solitary pursuit of a uniform diffusion coefficient, it is personally extremely satisfying and rewarding to have this important document published. We began this journey in 1983 when Lambert's law was the prevailing model of uniform diffusion. A boundary-plane goniometer was developed to measure and evaluate diffusor performance. These measurements, supported by boundary element method calculations, proved that we could improve on Lambert's law, without violating the second law of thermodynamics. Lambert's law deals with point scattering of incoherent high frequency sounds and is not applicable to diffusors [J. Konnert and P. D'Antonio, "Comments on Diffusing Surfaces in Concert Halls", J. Audio Eng. Soc., Vol. 37, No. 10, 839-844 (October 1989)]. The QRD, for example, explicitly uses wave interference (i.e. coherence) to produce its even diffraction lobes. For single plane (1D) diffusors we were able to show that an optimum diffuser scatters sound in the same way that a cylindrical source radiates sound. Autocorrelation metrics based on this have been highly successful in developing optimized quality diffusors that improve on earlier number theory designs initially introduced over 20 years ago . It then appeared sensible to describe an optimum (2D) hemispherical diffuser as one that mimics a spherical source. This indicates that a uniform intensity model better matches the philosophy of diffusor design practice. Based on this body of work, we now have the ability to design, predict, optimize, measure, evaluate, and move forward in standardizing the performance of sound diffusing surfaces. We encourage the acoustical consulting community to begin requesting diffusion coefficient data from manufacturers along with absorption coefficient data. In this way we can all begin incorporating diffusion coefficients into project specifications. For information on standards activities visit the web site at www.aes.org/standards. Further inquiries may be sent to standards@aes.org. If you are unable to obtain any of the draft documents from the website, please contact the Audio Engineering Society Standards Committee Draft Comments Dept. at 212-242-5589 or email: standards@aes.org.

RPG technology used in new Widescreen Review Laboratory



Widescreen Review®, "The Essential Home Theatre Resource™," will soon be moving into its new headquarters after outgrowing its old offices. Owners Gary and Marlene Reber, who founded the magazine and other WSR Publishing Inc. ventures, including WidescreenReview.com, SurroundMusic.net and WebDVD Publishing, have purchased a new 6,000 square foot building in Temecula (north of San Diego), to house their fast-growing enterprises.

A key element of the new building will be an 8,000 cubic foot (26-feet deep x 21-feet 8.6-inch wide x 13-feet 11.9-inch high) state-of-the-art reference theatre that will serve as Widescreen Review's and Surround Music's review laboratory. The theatre will have a dedicated rear-projection booth designed to optimally house projectors of all technologies, shapes and sizes. Video will be displayed on a seven-foot-wide AeroView Stewart Filmscreen. A time- and phase-accurate Dunlavy Signature Loudspeaker System will serve as the theatre's reference monitoring system. The system features six SC-V speakers (one used to reproduce the center channel in music-only playback and another to reproduce the surround back channel), one HRCC (for dedicated center channel movie sound), a SM-1 (to reproduce a height channel when appropriate) and two Tower TSW-5 Subwoofers.

Because of RPG's interest in education and research, Dr. Peter D'Antonio, President of RPG Diffusor Systems, Inc, collaborated with Widescreen Review to create a state-of-the-art listening laboratory designed to be accurate and yet flexible to adjust to the changing acoustical requirements for different music formats, multichannel music and movies and whatever the future holds. To accomplish this goal RPG used it Room Sizer room dimension optimization software to determine the best proportions for the A/V laboratory. Once determined the Room Optimizer software was used to determine the optimal positions for listeners and loudspeakers. A ceiling cloud design was chosen to provide a variable acoustics overhead structure, which integrated Skyline diffusors, a fabric covered opening for the overhead speaker, lighting and the possibility of controlling the decay time with rear-mounted absorption as needed in the future. For variable acoustic wall treatment, RPG's Variscreen was utilized. The Variscreen has now been used for a couple of years by Sony/Phillips in all of their demonstration rooms for SACD and has proven to be the most versatile acoustical tool in tuning problematic rooms. The Variscreen also accommodates Skyline diffusors for additional diffusion as needed.

For more details visit WIDESCREEN REVIEW® CREATING STATE-OF-THE-ART REFERENCE THEATRE AT NEW FACILITY. Look for Dr. D'Antonio's article on Minimizing Acoustical Distortion in Home Theaters in the next issue of Widescreen Review.

RPG restructuring representation in Europe
RPG is currently reorganizing its distribution in Europe. Please contact RPG USA directly if you are interested in representing RPG products in Europe. RPG is presently expanding its manufacturing capability in Europe and providing local representation in each country to lower the cost of its products, and provide quick and professional service to its European clients. Dr. Peter D'Antonio will personally be servicing all European acoustical consultants. This will allow easy collaboration on all optimization services that RPG offers using CHAOS. An example of how this is beginning to be a reality is the Edwina Palmer Hall. RPG invites all European acousticians to contact Dr. Peter D'Antonio and discuss the new arrangement. Dr. D'Antonio will be in Rome for the ICA in September and would like to set up meetings with interested European colleagues.

RPG publishes new absorption data for BAD^TM panels
New absorption data for RPG's 1" BAD panel in an A mounting, with 5/8" and standard ˝" holes is contrasted with a 1" fabric wrapped fiberglass panel. It can be seen that as the hole diameter decreases from 5/8" to ˝" the absorption above 1000 Hz is attenuated allowing this energy to be constructively diffused into the space creating a pleasing ambiance, instead of a overly damped sound field. In addition, below 1000 Hz the BAD panel offers additional absorption due to its membrane effect. The new 2" BAD panel absorption data illustrates the impressive extension to lower frequencies without additional high frequency absorption compared to the 1" BAD panel. In addition the 2" BAD panel absorption data is further contrasted with the absorption from a 1" BAD panel in an E mounting. When one utilizes the dedicated low frequency absorption, with 100% efficiency down to 40 Hz, for RPG's Modex, one sees the power of this new system approach. Thus, one can obtain high frequency absorption with an RPG Absorbor, mid-to-low frequency absorption with an RPG BAD panel, with high frequency diffusion, dedicated low frequency absorption with Modex or any combination to provide exactly the acoustical performance desired.

Announcing BASWA®phon: The smooth, seamless acoustic plaster system
Acousticians have long sought an absorptive, smooth, seamless and durable plastered finish to satisfy the aesthetic requirements of architects and clients. RPG® is now offering a new patented field-applied system that provides exceptional absorption, a strikingly beautiful appearance, with integral coloring and cleaning possibilities. BASWA®phon offers a long awaited solution and is finding immediate application in architectural acoustics. Read More

RPG Announces new Room Sizer Software and Describes The Algorithm at AES Amsterdam
Modes in small rooms often lead to extended sound decays and uneven frequency responses. In critical listening spaces, this causes unwanted coloration effects that can be detrimental to the sound quality. The problem arises at low frequencies because of the relatively low modal density. Many designers try to overcome the problems of modes by choosing an appropriately proportioned room and by the use of bass absorbers. This paper is interested in the former, the choice of room dimensions to minimise the coloration effects of modes. The paper starts by discussing previous studies by others, which have suggested optimum room ratios or design methodologies. Then a new method is outlined - this is based on numerical optimisation - and the old and new methods are compared philosophically. Results in the form of modal responses are given to demonstrate the power of the new method. Read More

Diffuse Seminars
RPG offers 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 Room Sizer, Room Optimizer, Shape Optimizer, CATT Acoustics software and Lake Technology convolution platforms. The press is also welcome. RPG is applying for AIA Continuing Education credits. The response to these educational seminars has been very enthusiastic. The 2001 seminar calendar will be posted next month.

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.