RPG Diffusor Systems

The Phoenix Symphony Orchestra had to find a temporary home for their 2004-2005 season while their permanent home, Symphony Hall, is being renovated. They moved into the existing, 1500 seat, Orpheum Theatre in Phoenix despite the fact that the historic, atmospheric theatre was primarily intended for amplified music performance. They worried that the large stage house would ‘soak up’ all the sound, leaving very little to be projected out to the audience. Complicating matters further for orchestral performance was the existing sound absorptive ceiling (an aspect of the hall that is actually favorable for amplified music performance.) The RPG VAMPS shell system provides the great onstage acoustics and projection into the hall the Symphony requires.

Acoustic Consultant

Mr. David Conant – McKay Conant Brook, Inc.
(Westlake Village, CA ~ www.mcbinc.com)

“The VAMPS offer unusually rich and warm sound on the performing stage for the Phoenix Symphony Orchestra. The sound is highly uniform across the stage even when musicians are centered on the spaces between the VAMPS. This speaks to the diffusivity of the units. The Symphony is very happy with the VAMPS and there is little I would change about how the sound behaves on stage.”

Music Critic - The Arizona Republic

Mr. Kenneth LaFave

“The Phoenix Symphony's temporary home for the 2004-2005 season is the Orpheum Theatre, thanks to ongoing renovation at Symphony Hall. And as a few thousand people heard TPS play its opening concerts at the Orpheum Thursday through Saturday, it should be a very good year. The Orpheum, outfitted with a new shell, is a dry acoustic space that affords much greater clarity than Symphony Hall. Saturday night, when artistic adviser James DePreist led the orchestra in an all-Beethoven gala event, winds had richer color, brass more focus and strings more depth than ever heard before. DePreist was able to bring off his conception of the andante to Beethoven's Fifth Symphony - in which the various voices have greater independence - in part because of the Orpheum's acoustics.”

Phoenix Symphony General Manager

Mr. Joel Levin

“The shell for the Orpheum has been a great improvement and will provide both musicians and our patrons with a much deserved higher-level musical product. The string sound, in my opinion, is better than in Symphony Hall, the woodwinds now pop out, and the brass and percussion are balanced as well. We had two over-flow season preview concerts this past weekend, and received many, many positive comments on not only the sound of the hall, but the attractiveness of the towers as well.”

Civic Plaza Director

Mr. Jay Green

“The acoustical towers and ceiling integrate very well into the decor of the theater and obviously greatly help the quality of the Symphony production.”

Deputy Director, Phoenix Stages Division
Civic Plaza Department

Mr. Robert R. Allen

“The circle is complete! THANK YOU ALL for your hard work and efforts toward solving a difficult problem. The Symphony is pleased, as is the Department Director. Congratulations for this significant accomplishment. My hat is off to you!”

Symphony, new home resonate
Kenneth LaFave
The Arizona Republic
Oct. 1, 2004 12:00 AM

With its temporary move to the Orpheum Theatre (owing to renovation of Phoenix Symphony Hall), the Phoenix Symphony has taken on a new sonic identity.

The orchestra we heard Thursday night at the Orpheum is a more transparent and color-rich ensemble than the thick, sometimes fuzzy one we heard for years at Symphony Hall.

What a difference a venue makes.

With the new sound, and this season's quest for a music director to replace Hermann Michael, comes the once-in-a-decade (or so) possibility for this orchestra to nurture a new interpretive freedom and confidence.

Thursday night's concert, for example, ended with Liszt's symphonic poem Les Preludes in a performance that guest conductor Giancarlo Guerrero led with passion and abandon, an energy the orchestra could not match.

Guerrero seemed from about two-thirds of the way through until the end to be trying to coax more out of the orchestra than it could supply - until the final measures, when the heavens at last opened and Liszt's torrential emotional cloudburst drenched the hall.

This was a freshly thought-out program, opening with Jennifer Higdon's tiny overture, Machine - a bristling evocation of what it means to pop out notes like so many rivets and screws - and proceeding with a stellar performance of the Schumann Piano Concerto; Benedetto Lupo, soloist. The second half brought Mozart's too-seldom heard Linz Symphony (No. 36 in C) and Les Preludes.

The Schumann was a perfect marriage of Romantic composer and masterful interpreter. Lupo made no bones about the flashy nature of the first movement. The astounding cadenza was a fireball under Lupo's control. The interplay of soloist and orchestra in the last movement was handled with flair by Lupo and Guerrero.

Guerrero, a large-framed man with surprisingly puckish grace on the podium, was at his pinnacle in the Mozart, culling from the orchestra an attractive lightness and ease.

RPG Optimizes the Main Theater of the National Museum of the American Indian
RPG is proud to have collaborated with Jaffe Holden Acoustics and Polshek Partners on the acoustical optimization of the circular main theater in the National Museum of the American Indian.

Early rendering of main theater

Vertical wood paneling surrounding the 322 seat circular theater, evoking a dense hard wood forest, and above a dark blue ceiling twinkles with constellations. Like many of the spaces, the auditorium engages all of the senses. The main theater is a storytelling vehicle: a clearing in the forest under the night sky. Indeed, this space in the round with its vertical textured and detailed wood walls conjures up a pine forest, and the midnight blue acoustical ceiling, replete with twinkling “stars,” completes the effect. A surrounding lateral aisle allows actors into the audience, a necessary component of many American Indian performances.

Acoustician Steve Haas, working with Jaffe Holden Acoustics, Norwalk, CT was concerned that the circular room, shown in the RPG model, would provide focusing problems and Damyanti Radheshwar from Polshek Partnership and the design team devised an undulating and tilting façade on the circular walls, which was very rough and diffusive in the rear and gradually became reflective next to the screen. This can be seen in the half plan illustration. The design team of Haas and Radheshwar asked RPG to acoustically model the topology of the wood paneling to provide uniform sound diffusion and

RPG model of main theater

Half plan of the main theater showing how the diffusive rear wall gradually transitions into a reflective surface where it meets the projection screen in the lower left of the illustration.

minimize focusing. RPG utilized its proprietary Shape Optimizer to optimized the undulating pattern to provide uniform scattering.

The process involved the use of RPG’s FlutterFree planks interspersed with flat wooden planks, the depth and positioning of each optimally determined by the Shape Optimizer.

The proposed arrangement by Polshek Partnership was evaluated and optimized. The angular response is shown at 1.5 kHz, as well as the diffusion response, which is a summary of the uniformity of the angular response at all frequencies. The final design of a repeating Diffractal section is also shown.

Angular response of original proposed Polshek pattern, an improved similar pattern, an optimized pattern and a flat panel.

Diffractal section pattern utilizing FlutterFree on main theater walls.

Comparison of the diffusion coefficient for the proposed pattern, a flat panel and the optimized design.

Tyndall Medal Awarded to Dr. Trevor Cox
Dr. Trevor J. Cox, head of RPG’s Theoretical Modeling Group, receives prestigious Tyndall Medal at Institute of Acoustics Ceremony.

ISO Scattering and Diffusion Coefficient Measurement Methodology Standardized
Measurement and characterization procedures for scattering surfaces now standardized.

In the past 30 years, significant progress has been made in designing, optimizing, characterizing and now standardizing scattering surfaces. Acousticians now can specify the scattering and diffusion coefficients, in addition to the random incidence absorption coefficient. This research has led to progress in room acoustics and computer modeling. Two standards have emerged.

1. Scattering Coefficient: A scattering coefficient is a measure of the amount of sound scattered away from a particular direction or distribution. This has the greatest similarity to the coefficients required as inputs to geometric room acoustic models.
ISO 17497-1:2004
Acoustics -- Sound-scattering properties of surfaces -- Part 1: Measurement of the random-incidence scattering coefficient in a reverberation room (available in English only). To order go to ISO Store

2. Diffusion Coefficient: A diffusion coefficient measures the quality of reflections produced by a surface, in the case of the AES coefficient, by measuring the similarity between the scattered polar response and a uniform distribution. It is a measure of diffusor quality.
2.1 "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).
2.2 This information document is in the process of being added as Part 2 to the ISO 17497-1:2004 standard.

RPG Launches New Technologies As This Year's CEDIA EXPO Breaks Attendance Records Yet Again
RPG launches new bass management system, utilizing Modex Plate and Broadband technology, providing low frequency control down to 50 Hz in a thickness of 4”.

RPG displayed their new Bass Management System, utilizing the Modex(TM) Plate and Modex(TM) Broadband technologies, now allowing low frequency control down to 50Hz in just 4" of depth. This brings RPG's high performance line of Residential products full circle, offering designers and integrators complete room acoustic packages utilizing Diffusion, Absorption, Diffsorption and Bass Management capability in just 4" of depth.

RPG Modex™ Plate

RPG ModexTM Plate: Low Profile Bass Management System

Now available for the first time - a Bass Management module for residential media and entertainment environments that is capable of absorbing frequencies down to 50Hz in just 4” of total depth. Suitable for surface mount wall and ceiling applications. Maximize the performance and dollar investment in your subwoofer system - Now you can control more bass in less space! (Stand shown is for display purposes only.)
Finishes: White (Powder Coat)
Size: 59-1/16” x 39-3/8” x 3-15/16”D MSRP: $999

CEDIA is an international trade association of companies that specialize in designing and installing electronic systems for the home. The association was founded in September 1989 and has more than 3,000 member companies worldwide. CEDIA members are established and insured businesses with bona fide qualifications and experience in this specialized field. For more information on CEDIA, visit the association’s web site at www.cedia.org.

Maximize The Surround Experience™

RPG provides Bi-Weekly Acoustical Continuing Education Series Diffuse Bulletins
Diffuse Bulletins provide acousticians with continuing education series. dBv1i9 and dBv1i10 now posted. Read More

Sign up for the last Diffuse Seminar in 2004
The next Diffuse Seminar and the last one in 2004 will be held at RPG on November 19. Since these seminars are becoming very popular, we suggest you contact your local rep and sign up as soon as possible to guarantee a seat. Read More.

RPG seminars accredited by AIA Continuing Education System
RPG now offers four AIA/CES accredited seminars on various aspects of architectural acoustics.

The Next Generation of Acoustic Finishes, Shapes and Services
( AIA/CES AF1011 1 LuHour )
Participants learn how recent innovation and technology has resulted in a much broader variety of architectural finishes, shapes and services that solve age-old acoustic problems in the built environment.

Acoustical Diffusor Design/Computerized Shape Optimization
( AIA/CES DD1011 1 LuHour )
Participants learn the basic theory and history of sound diffusion as well as why sound diffusion is so essential in critical listening environments. A variety of methods, materials and products for diffusing sound will be presented.

Minimizing Acoustical Distortion in Critical Listening Spaces
( AIA/CES AD1011 1 LuHour )
Participants learn how sound reproduced in a critical listening room can be affected, positively or negatively, by a room's architectural surfaces prior to it arriving at the ears of a listener. A variety of methods, materials and products for minimizing the negative distortion of the reproduced sound are presented.

Desktop Acoustic Auralization of Architectural Spaces
( AIA/CES CA1011 1 LuHour )
Participants learn how recent innovation and technology in computer modeling has resulted in a reliable method for predicting the quality of a room's acoustics prior to its construction. Basic theory and examples of its application in practice are presented.

	New Additions Watch this section for new additions to the website.

Recent Completed Projects Q3-2004
Included is a partial list of architectural, home theater and project studio completed projects.