A diffraction physicist reads Physics Today.

RPG’s story, as the company told it on its old website, begins in October 1980 at the Naval Research Laboratory in Washington, DC, where Peter D’Antonio worked as a diffraction physicist in the Laboratory for the Structure of Matter. A colleague handed him that month’s Physics Today, which carried Manfred Schroeder’s article “Toward better acoustics for concert halls” — published in the October 1980 issue, as the journal’s records confirm — proposing surfaces based on number theory that scatter sound evenly. D’Antonio, also a musician and recording engineer, wanted to use them in a private studio he had built, Underground Sound, in Largo, Maryland.

With his laboratory colleague John Konnert, D’Antonio treated Schroeder’s “reflection phase gratings” as two-dimensional sonic crystals that could be modelled with the same diffraction theory used in X-ray crystallography, the company’s history says. The pair presented their first paper on Schroeder diffusers at the 74th Audio Engineering Society convention in New York in October 1983, and that year D’Antonio founded RPG Diffusor Systems, Inc. — RPG stands for reflection phase grating. A 2014 chairman’s message on the old site said he had started RPG “as an intellectual curiosity in my garage.”

The early work was in recording studios. The company’s history names the Oak Ridge Boys’ Acorn Sound Recorders in Hendersonville, Tennessee, designed by Bob Todrank, as an early project, and studio designers including Russ Berger, Neil Grant and John Storyk as early users. Its timeline lists the RFZ/RPG control-room design in 1984 and the QRD 734 diffuser in 1987. For decades the company was based in Upper Marlboro, Maryland, between Washington and Annapolis; its old site described a 25,000-square-foot building there with computerised manufacturing and painting, research and listening labs, and said it had moved in during 1992.

Diffusers, coefficients and a textbook.

RPG’s product names read like a lab notebook. Its timeline lists the Abffusor (1989), which combines absorption and diffusion; the two-dimensional Omniffusor (1990); DiffusorBlox, diffusing concrete blocks, and the fractal Diffractal (1993); Skyline (1995); the BAD panel (1998); and the Modffusor and the curved Waveform surfaces (2004). Many are registered marks, and the company has long described them as patented. Its old site said it made products in wood, fibre-reinforced gypsum, concrete, plastic and fibreglass from its own moulds, and that it kept “complete parallel manufacturing in the United Kingdom” for European distribution.

The science is better documented than for most acoustic brands. D’Antonio co-wrote Acoustic Absorbers and Diffusers: Theory, Design and Application with Trevor Cox; the company dates the first edition to 2004, and CRC Press published later editions, the third in 2016–17. RPG’s timeline says D’Antonio proposed a diffusion coefficient in 1991 and chaired the Audio Engineering Society working group on acoustical materials, which produced the AES-4id-2001 document on measuring how evenly diffusers scatter sound; ISO 17497-1, on scattering coefficients, followed in 2004. The company’s old biography said he was a Fellow of the Acoustical Society of America and of the Audio Engineering Society, and an adjunct professor of acoustics at the Cleveland Institute of Music.

The clearest independent recognition came in 2024. In March that year the Journal of the Acoustical Society of America published the society’s Wallace Clement Sabine Award for 2023 to Peter D’Antonio — an award for individuals who have furthered knowledge of architectural acoustics. RPG says the medal was presented at the society’s meeting in Ottawa that year, and that D’Antonio is a member of the music industry’s TECnology Hall of Fame.

The client list the company publishes is long and its own: it has named Carnegie Hall, Lincoln Center, studios for Peter Gabriel and Whitney Houston, Juilliard and Berklee. Its recent case studies include a Spotify studio, Klarman Hall at Harvard Business School and listening rooms for Polk Audio.

Acoustic treatment as a brand.

The seven brands here make the same kind of thing: objects that change how a room sounds. Absorbers soak up reflections, bass traps tame low frequencies, and diffusers scatter sound rather than remove it. Customers run from recording studios to home cinemas.

Four are North American. GIK Acoustics was founded in Atlanta, Georgia, in 2004 by the musician Glenn Kuras; it says its panels are built to order in Atlanta and, for the EU, in Kielce, Poland, with UK orders fulfilled from Bradford, England, where its European arm started in 2008. Auralex, which Eric Smith says he founded in his garage in 1977, is based in Indianapolis. Primacoustic, in Port Coquitlam, British Columbia, began in 2000 as a division of Radial Engineering; Radial says its founder, Peter Janis, sold the company to Regimen Equity Partners in 2018.

RPG, which Peter D’Antonio founded in 1983 around what it calls Reflective Phase Grating diffusors, now trades as RPG Acoustical Systems, LLC, from Passaic, New Jersey, its website says.

Three are European. Vicoustic was founded in Portugal in 2007 and has its headquarters and research centre in Paços de Ferreira; the brand is owned by Visound Acústica SA, and in 2026 it said it had joined forces with United Acoustic under the name UniVicoustic. Artnovion is run by Artnovion Lda, a Portuguese company whose EU-funded projects are registered in the country’s Norte region. t.akustik is the house label of Thomann, the family-owned music retailer in Treppendorf, Bavaria.

This guide sets out what can be checked about each brand — who founded it, who owns it, and what it says about where its products are made — and marks clearly what rests only on the company’s own word.

A new entity in Passaic.

The business changed shape in 2017. RPG says that year “a new entity known as RPG Acoustical Systems, LLC was established” to carry on making and selling its absorption, reflection and diffusion products at a facility in Passaic, New Jersey, and its website has given a Passaic address since at least 2018. The company does not name the owners of the new entity. In 2019 the site described a renovated factory of more than 90,000 square feet about fifteen miles west of New York City, with a test laboratory named the Dr. Peter D’Antonio Acoustical Research Center, or ARC, which it said would be one of North America’s largest reverberation chambers. A 2025 company press release names Jeff Madison as RPG’s president.

On where products are made, the company makes two kinds of claim. In 2023 it said a select list of its wood and fabric products — including the QRD 734, Omniffusor W models, Skyline and Flutterfree — could now be manufactured within the EU by a European partner, with other items made at its US facility; in 2025 it announced a renewed alliance with Acoustic GRG, a British manufacturer it calls its exclusive UK licensee. Its 2026 Perfecto Micro QSP, a laser-micro-perforated wood panel, is described as “manufactured in the USA” using its in-house laser technology. The company also markets SoniQ, a technology it says turns office furniture into sound absorbers, and online tools for comparing products and visualising perforated finishes.

For a design guide, RPG shows how a brand can be built on the language of physics — reflection phase gratings, number sequences and coined product names — rather than on a look. Compare Auralex, which says it was founded in 1977 to make acoustic treatment more affordable, and Genelec, the Finnish studio-monitor maker. For this guide we use walnut, ink navy and gypsum white with a technical sans, an unofficial interpretation; no product or logo is reproduced.

Keep RPG Diffusor Systems’s identity on hand — save it to a board in the Made Good inspiration library.