Dr. Peter D’Antonio, president of RPG® Diffusor Systems, Inc., received his Ph.D. in Chemistry in 1967 from the Polytechnic Institute of Brooklyn. He has published numerous scientific articles in technical journals and magazines, and his research is referenced in many acoustical texts. He currently serves as Chairman of the AES Subcommitte on Acoustics for the Characterization of Acoustical Materials and is adjunct professor of acoustics at the Cleveland Institute of Music. His many professional memberships include the Acoustical Society of America, National Association of Broadcasters, Audio Engineering Society, National Sound and Communications Association, and Sigma Xi.

When you listen to your next CD, movie, video, radio broadcast, or live concert, you may not realize it, but you are hearing RPG® acoustical treatment technology at work. RPG® has played a supporting role in every facet of the entertainment industry for 13 years. But until recently, RPG® products were the industry’s best-kept secret to home audiophiles. Now that RPG® has expanded into the residential market, we thought it was a good time to pick the never-idle brain of RPG® founder and designer Peter D’Antonio.

Audio Advisor
Peter, I understand that until recently RPG® was your second career. What was your first?

Dr. Peter D’Antonio
In 1967 I received a Ph.D. from the Polytechnic Institute of Brooklyn in Chemistry with a minor in X-ray Crystallography. Following graduation, I began a rewarding basic research career at the government’s Naval Research Lab (NRL) in Washington, D.C. — founded by Thomas Edison.

While at NRL, I worked in a special division called the Laboratory for the Structure of Matter. My last assignment was a NASA-funded project to determine the mechanism for protein crystal growth in solution using an atomic force microscope. My wife often jokes that nothing has changed since my retirement from NRL this past January to devote full time as President/CEO of RPG® — because instead of working 40 hours a week at two jobs, now I work 80 hours a week at one.

Q
When did you first get interested in acoustics?

A
Prior to forming RPG® in 1983, I had a previous second career as owner and recording engineer of Underground Sound Recording Studios, which I built and wired in the basement of my home. Underground Sound grew into a full-time commercial recording studio, where we worked with an interesting mix of clients including classical, funk, new wave, Irish, madrigal, country, religious, and my own group. As a recording engineer, I began to realize the importance of the room I was hearing.

At one point I decided to redesign the layout and acoustics of the studio and control room. I did a literature search and was surprised to discover really only one scientific new approach called Live End Dead End by Don and Carolyn Davis of Syn-Aud-Con. Dick Heyser was at this time suggesting the use of Time Delay Spectroscopy (TDS) for acoustic analysis. Thus the TEF analyzer made it possible to verify the merits of the LEDE approach, and I began fervently embracing this emerging technology and promulgating its use.

Q
What direction did your approach take?

A
Following the precepts of LEDE, but with the assistance of John Konnert, a brilliant mathematician, we were able to use diffraction physics to simulate the scattering in the control room to develop optimum ways to provide a front end which provided full-spectrum attenuation and a “live” end which provided wide angle, broad bandwidth diffusion. The “dead” end was achieved using splayed absorptive side walls and ceiling which created a reflection-free zone or RFZ.

To create the “live” end, I began investigating the number-theory research of Manfred Schroeder, who headed the Acoustic Division at Bell Labs and was also the head of the Acoustics department at University of Goettingen in Germany. Schroeder suggested that number theory sequences developed by Karl Friedrich Gauss in the 18th century could be used to create surfaces which scattered sound uniformly in all directions over a wide range of frequencies. These new surfaces were called reflection phase gratings, or RPGs.

Q
Tell us about the early days of RPG®.

A
A spare bedroom housed our corporate offices, my living room housed our supply of plywood, and the cutting and assembly areas were in my back yard. This was in suburbia and I had a teenager at home. All of his friends were our assemblers, and some of their mothers were our office workers. With a recording studio in the lower basement and a manufacturing company in the upper house and back yard, this was quite a bitter pill for my neighbors to swallow, but they were into it.

It was quite a sight on a summer night when the freight trucks would pull up to my door for the daily RPG® deliveries. We were shipping all over the country, and as orders continued to increase to the point were we couldn’t keep up, we made the move to a commercial park where we rented a small space and set up production. Those were heady days and we were getting orders from all over the world.

Q
Who were your first customers?

A
Designer Russ Berger began embracing our technology and specified RPG® technology in all of his new studios. Russ provided us with a very profitable project for Jimmy Swaggart Ministries which helped propel RPG® forward. Russ’ projects included facilities for Steve Miller, National Public Radio, most of the major TV and radio networks, Mariah Carey, Sony Music, etc.

Neil Grant, an aspiring studio designer from London, singlehandedly put RPG® on the map in Europe. His projects included many of the studios in the late and post-Beatles era in London, including SARM, Swan Yard, BBC, etc. One really challenging and interesting project with Neil was Peter Gabriel’s RealWorld Studios in Bath, U.K. This was followed by a host of European as well as American facilities, including the famous Hit Factory, Mutt Lange, Sony Classical, and the most recent jewel for Reba McEntire in Nashville.

Q
What’s the newest field RPG® is currently developing?

A
RPG® has wandered into the residential listening room market. With a limited amount of resources, we had decided that business-to-business was RPG’s niche. This all changed with the advent of home theater, because now the intricacies of home theater design, system integration, and increased cost of installation has brought the acoustical consultant and system integrator into this market in a big way. The other reason for my interest in this market is that it presents a new challenge.

In 1983, we discovered how to design a room to listen to two-channel stereo in the most effective way. Today, we have to re-discover the most optimal room design to appreciate discrete 5.1 reproduction. We have devoted all of our resources to providing the latest in acoustic research to create these environments with the many design, measurement, simulation, and listening tools we have available. What we have developed is called AcousticTools® for Home Theater, and once again my juices are flowing!

Q
Apart from home theater, what's RPG®’s newest product innovation for audiophiles?

A
I think this would have to be our new fire-safe Melaflex foam products. Foam has provided the audiophile with an inexpensive entry level product to absorb interfering reflections. While we have demonstrated that — in addition to imaging control — bass tools and spatial tools are important, improving imaging and controlling flutter echo in a room are very important, and it is easy to hear the improvement.

Q
What sets Melaflex apart from other foam acoustic products?

A
RPG® has been reticent to offer a foam product in the past because of the potential fire and smoke hazard of urethane foam, which is what most sculpted foams were fabricated from. Recently, RPG® gained access to a new completely fire-safe foam made from Melamine. The only problem was that Melamine was much more expensive than urethane foam, so we had to find a way to use less foam and provide the same level or better performance than urethane.

Q
How did you accomplish that?

A
We went to the drawing board and looked at the mechanism of how sound is absorbed by a porous material. In a porous material, sound is actually converted to heat by friction in the voids of the porous material. This absorption is maximized when the air particles are moving most rapidly through the porous material. Our research shows that at the wall surface, the air particles are at a standstill. This is similar to a car crashing into a barrier. At the barrier, the car’s velocity is zero. So, it’s useless to place porous absorption directly on a boundary surface or directly in contact with a corner, because there is no air movement and hence no absorption. The porous material there is only acting as a mounting mechanism for the outer absorbing material.

Despite this reality of acoustics, it is quite common for audiophiles to mount porous material on a wall or directly in a corner. Our research indicated the goal was to space the greatest volume of foam as far away from the wall surface as possible. This led to the patent-pending Variable Depth Air Cavity or VDAC™ designs incorporated into RPG®s SoundWave, SoundRound, and SoundCorner Melaflex products.

Q
How much of an acoustical palette can you achieve with foam products?

A
In all of our room packages we incorporate an imaging tool, a bass tool, and a spatial tool. The imaging tool can be the SoundWave, SoundRound, or SoundFlat panels. The bass tool is the SoundCorner, which positions a 2' Melaflex panel across the corner as far as possible from the corner. The spatial tool was a little more difficult to achieve with porous foam. To accomplish diffusion, we relied on an acoustic principle called variable impedance.

RPG® achieves its patented sound diffusion by varying the surface topology to create a reflection phase grating. Well, diffusion, albeit not as efficient, can also be achieved by varying the impedance of a surface by placing alternating reflective and absorptive patches on a wall. Thus, since the SoundRound consists of five separate half-round strips, we could space these on a wall to provide limited diffusion. And so we have defined a new entry-level, fire-safe Melaflex package that audiophiles can obtain to improve their listening rooms for a very cost-effective price. Along with AcousticTools and ClassicPlus, we now can offer Audio Advisor customers good, better, best performance with three packages that allow upgradability to achieve the ultimate performance in a small package.

Q
Why should audiophiles favor RPG® over other acoustic products?

A
RPG® is unique in the music industry. To the acoustical consultants, designer, specifiers, and music industry insiders, RPG® has earned the reputation as the acoustical reference of the musical and acoustical industries. Let me summarize why I think an audiophile should trust in RPG:

1) RPG offers the widest range of absorbing and diffusing products in the industry.

2) All of RPG®’s products are painstakingly researched and documented and are provided with proof of performance testing date.

3) We are recognized worldwide as being on the leading edge with numerous publications and awards.

4) RPG offers complete packages for room designs, as opposed to just absorbers, diffusors, or Bass Traps, to address all of the commonly encountered problems.

5) Our prestigious client list. RPG’s philosophy for room design has been used in most of the industry’s leading facilities, from private facilities for Peter Gabriel, Whitney Houston, and Reba McEntire, to leading commercial facilities such as the Hit Factory and Sony Music, to leading mastering facilities such as Sterling and Bob Ludwig’s Gateway Mastering, to record companies such as CBS, Polygram, RCA, DMP, Telarc, Sony Classical, to radio/TV facilities such as ABC, BBC, CBC, NPR, NBC, etc.

6) The endorsement of RPG® by industry professionals, including every Mix Magazine Technical Award Winner for studio design/acoustics, including Bob Todrank, Chip Davis, Russ Berger, and John Storyk.

7) Cost-effective prices, including affordable AcousticTools and Melaflex packages.

8) Attentive and professional technical support, as anyone who has ever called RPG® will attest. Just as in acoustical research, RPG® technical support and documentation define the industry standard.

Q
Any chance you’ll be cutting back on the 80-hour work weeks?

A
Since my work has always been a labor of love, I could easily have a sticker on the back of my car reading, “I’d Rather Be Working!”


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