Frequency and Depth

Meet the man building his own sound diffuser panels for better listening

In Thu Duc District in Ho Chi Minh City, accountant Pham Khac Tuong is turning discarded wood into one-of-a-kind, handmade sound diffuser panels worth thousands of dollars. Used by professional musicians or the most discerning music lover, a sound diffuser is an acoustic panel used to treat echoes and reflections. If that sounds similar to sound absorption panels, then it is—because on the base level the sound diffuser and sound absorber function on the same acoustic principle of using certain materials to affect sound waves. Instead of absorbing sound energy, however, a diffuser disperses sound waves on particular frequencies, thus giving extra depth to and increasing the musical quality of sounds.

Oi Vietnam-Jan2016_audio__DSC4660_NT copy

“It filters, magnifies and enriches sounds all at once,” explains Tuong. “That may not sound very impressive on paper, but in real practice that is the difference between listening to an old cassette tape in a cramped shoebox apartment and listening to a full-blown orchestra in an auditorium.”

There are a number of different diffusers, with each specialized for specific sound ranges, from bass to soprano. The more popular ones include maximum length sequence diffusers, quadratic residue diffusers, primitive- root diffusers, and hemispherical diffusers.

Sound diffusion is an exact science. High-quality sound diffusers, like expensive bespoke ones, are custom- designed to a specific space and sound range. Tuong says the idea of making his own came out of necessity. “You cannot buy diffusers in Vietnam,” he claims, “because nobody sells them. The closest manufacturer is in Europe. And even if you are willing to shell out USD600 plus 40kg worth of global shipping charges per panel, those generic store-bought panels are not going to fit the acoustics of your room to a tee.”

The first sound diffuser Tuong made was in 2011 and took him two years of research before the actual project took off. “A hemispherical diffuser is not something just about anybody can build. It takes a lot of skill, knowledge and interpersonal resources,” he points out. With the help of audiophiles in his circle and studying from books such as Robert Harley’s The Complete Guide to High- End Audio and John M. Woram’s Sound Recording Handbook, Tuong educated himself on topics such as soundstages, harmonics, and the Helmholtz resonatorprinciple. He measured the resonance of his room with equipment borrowed from a friend who worked at the city conservatory and mapped out an exact configuration using an acoustic auralization software.

After designing was done, the panel itself took a month to complete. For materials, Tuong collected old pinewood crates, broken fences or tables from recycling centers and even waste byproducts from carpenters’ workshops. “Pinewood is considered junk by furniture factories, but it is actually the best building material for diffusers. Anybody who knows a thing or two about musical instruments knows that wood conducts sound beautifully. Commercial diffusers in stores are usually made of styrofoam to save cost, but styrofoam is only number three on the scale of sound conductivity.”

The pinewood Truong collected was laser cut into 841 rectangular blocks of various lengths by commissioned woodworkers, and then painstakingly assembled piece- by-piece by Tuong and his family over the course of a month into the final product: a hemispherical sound diffuser panel made out of solid pinewood. The panel weighs over 40kgs. Affixed to the wall like a piece of art, the effect the diffuser has on the acoustic resonance of Tuong’s listening room is something he says has to be experienced in person.

“The reason I wanted a diffuser in the first place is because I noticed no matter how good the sound system, music from home audio still isn’t on the same level as live performances. I won’t say having a sound diffuser in your room erases that difference, but it’s certainly getting there.”

Since building his first diffuser in 2011, Tuong has made several more, one of which is a monstrosity as big as four other panels combined. He hangs the big one from the ceiling to further improve the acoustics of his listening room. He likes the sound of guitar clear and deep.

As far as Tuong knows, he’s the only one in Vietnam who has ever successfully built a hemispherical diffuser. Friends, acquaintances and those who know about his work have asked if he plans to make a business out of building diffusers. As of now, Tuong’s answer is a solid no. “I’m happy with my accounting job,” he explains. “Perhaps in the future when I’m near retirement. In the meantime, I’ll gladly share my experience with fellow connoisseurs who want to build their own diffusers.”

Images by Ngoc Tran

Share this story, choose your platform!

Share on facebook
Share on twitter
Share on pinterest
Share on tumblr
Share on google
Share on linkedin
Share on reddit
Share on vk
Share on email
About the author:

Leave a Comment

Proving Provenance

Protecting intellectual properties in ASEAN countries using blockchain, IoT and NFC technology Counterfeit goods can be replicas or first copies, making it impossible for the layperson to differentiate. These counterfeit products can be as expensive as the originals. According to a recent survey by the Vietnam Directorate of Market Surveillance, 80 percent of consumers buy

Read More »

The Night Never Sleeps

Experience the Pulsating Energy of the City’s Nightlife at Atmos and Kasho Clubs It’s rare that the darkened, red neon- streaked quarters of Atmos Club (2nd Floor, 153 Ton That Dam, D1) aren’t at least mostly filled with patrons, almost all young Vietnamese clients who seem to have walked out of fashion magazines dressed defiantly

Read More »

Roar In The New Year

The dance is believed to bring fortune, but how is the costume made “Lions and Dragons are symbols of luck and prosperity. For the Vietnamese, without luck there is no life,” says Nhu Tra, a dancer from the Ha Nhan Duong troupe. “Which is why you will see lion dancing not just around Tet but

Read More »

App Learning

Enzo Smith talks about the creation of his Vietnamese language learning game app Did you study a language for multiple years in high school or college? Did you learn a language while studying abroad? Now ask yourself if you could hold a basic conversation in that language if somebody fluent were to come up to

Read More »

Gift Guide December 2019

Sunken Treasures Beneath the murky surface of the Brokopondo Hydro Lake in Suriname, South America, lies a hidden treasure that’s over 60 years—a 150,000-hectare underwater tropical forest. However, harvesting this submerged wood is difficult because divers must venture 15 meters deep into the lake to recover it. Through innovation and technology, Brokopondo Lakewood (www.facebook.com/Lakewoodvn) brings

Read More »

The Art-Tech Revolution

Seven expert opinions on how mediation and legal-tech are revolutionizing art provenance The right to resale royalties, or droit de suite, is the right of artists to receive a royalty payment each time their work is resold at an appreciated value. This viewpoint has historically been aimed at the likes of recording artists and filmmakers.

Read More »