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When Sound & Communications needed some industry perspective on diffusion, they decided to go to the source. Acoustics First has been developing sound diffusers for decades, and has done some of the most comprehensive research on developing testing standards for diffusion and reflected acoustic energy with the ASTM.
Acoustics First’s chief science officer, Jim DeGrandis, covers why diffusion is so much more complex than absorption in the February 2020 edition of Sound & Communications.
Acoustics First would like to remind everyone that it’s the little things that matter…
…remember to wash your hands and stay safe.
The importance of sound in culture, entertainment, safety, communication, and in defining the human experience is many times taken for granted – but not this year! 2020 has been designated the International Year of Sound, and throughout the year will be many special events focusing on the impact of sound and educating people about the importance of sound in enriching our lives.
Kicking off this worldwide event was an opening ceremony held on January 31st, in Paris at Sorbonne Grand Amphitheatre – which included supporters from across the globe who came to celebrate sound! Acoustics First was there to support this launch!
There were talks from many prominent members of the acoustic and physics societies including:
Prof. Gilles Pécout (Rector, Académie de Paris)
Prof. Jean Chambaz (President, Sorbonne Université)
Prof. Mark Hamilton (President, International Commission for Acoustics)
Christian Hugonnet (President, La Semaine du Son)
Prof. Vincent Gibiat (President, Société Française d’Acoustique)
Prof. Michel Spiro (President, International Union of Pure and Applied Physics )
Dr. Shelly Chanda (World Health Organization Representative)
Marion Burgess (IYS2020 Co-Organizer)
Prof. Jean-Dominique Polack (IYS 2020 co-organizer)
Prof. Michael Taroudakis (Moderator)
They debuted a short film produced by the International Commission for Acoustics and sponsored by i-ince called “Sound of our Life” directed by Antonio Fischetti – which shines a light on the different ways noise and sound impact our lives.
There were two sound exhibits at the ceremony, showing different ways to use speaker arrays and for different reasons. One was for a driver and passenger listening to different music in a car, the other was a novel sound pillar that had different sounds travelling around the circumference.
There were also two cultural music events. The first was a musical interlude performed by Maxime Perrin (accordion) and Samuel Thézé (bass clarinet). The second was the “Révolutions Vocales” concert performed by Compagnie VocAliques, which was translated into English for this international audience.
Following the ceremony was a reception in the beautiful ballroom, where attendees could reflect on the ceremony and discuss the different events planned for this year.
Check out the Official International Year of Sound website at https://sound2020.org/
When RPN magazine needed an article to teach readers how to improve their room acoustics, they turned to Acoustics First® to get the scoop.
YOUR ROOM’S ACOUSTIC SYSTEM – and How to Improve It
Ever wonder why some rooms sound better than others? What components contribute to
perception of sound in a space? What knowledge do you need to solve the sound problems that
When people read the heading “The System,” there will be a great number who assume I am
talking about the “sound system” in a room – the speakers, amplifiers, signal processors, and
other electronic components that generally produce sound in a space. This is only part of the
acoustic system that creates the soundscape we hear when we are exposed to sound in a space.
Yes, sound comes out of speakers, and they are important, but the source of sound isn’t what
gives us a perception of the space we are in – it’s the space itself!
The walls, ceiling, floors, seats, sculptures, drapes, artwork, construction, and even people in the
space are all contributing to how we perceive that sound source in any given acoustic
environment. I’m not saying that the speakers aren’t important – but they are just the source of
If you have a room with a 5-second reverb time, it doesn’t matter what type of speakers you
have, any sound they make is going to continue to be heard for five seconds – as is every sound
What does this mean? Even if you have the best speakers in the world in that room, it will sound
terrible (unless you are listening to Gregorian Chants…then it will sound awesome.)
However, if someone is speaking at a normal rate of speed, it will be unintelligible after the first 2
or 3 words – as those words will continue to bounce around with the sound of the next 15
words…like listening to 15 people all saying different things at the same time.
Your room is an acoustic system – from the sound source, to the ears of the listeners – as well as
everything in, around, and even outside of that room.
Have you ever watched an acoustical consultant begin the analysis of a new space? It’s
fascinating. You will undoubtedly see them walking around the room while making noises –
clapping their hands, snapping their fingers, whistling, even talking loudly, shouting, and singing.
It’s as if they are bats using different sounds to figure out the characteristics of the room they are
in. They are, in fact, analyzing the room’s acoustic system. Where does sound reflect? Are there
echoes or flutter? What is the character of the reverb? They look at the structure, materials,
corners, architectural elements, floors, carpets, walls, windows, doors, ceilings and more.
Note: They begin this analysis WITHOUT using the speakers.
Why? If the room is bad, your speakers will not fix it.
What are they doing? They are listening. That’s it. Nothing fancy here – just listening.
I will say that many acousticians have done this so many times, in so many different spaces, that
they have an idea of what the room is going to sound like, without even making a peep – just by
looking at it. What are they looking for? What are they listening to? What can you learn from this?
Time to Listen
Everyone has a room where they dislike the acoustics. Go in there. Clap your hands. What
happened? Clap again. Snap your fingers. Make some noise – but make sure to listen. Where is
the sound coming from? Turn around, clap again. Walk to another area…clap.
As you walk around, you will hear the sound change. Turn your head. Is the sound coming from
the corner, the ceiling, both? Angle your ears in between two corners. Maybe that’s where it’s
coming from. Is there a large open balcony or a curved wall? Ask yourself these questions as you
walk around and listen.
Are any of the surfaces hard? What about the floor? Is the sound lingering over your head up in
the ceiling? Is there a defined slap off the back wall when you clap your hands? Is there a ringing
noise? Does the echo wash over you and linger?
Sharpen your listening skills. Map the room with your ears.
What Are You Doing in the Room?
This is an important question. For most uses involving speaking and understanding speech, there
are some good general targets. For example, for most rooms over 100m3 (15’ cube), a 0.8 to 1.7
second reverb time is ideal for many different functions.
However, keep in mind, some spaces may have special reverb requirements. If you’re doing
Gregorian Chants, a three to five second reverb time is still great!
Now, How Do You Fix It?
Most rooms are going to benefit from reducing the acoustic energy in the space. Absorption is
the most direct and easy to understand method – add soft stuff.
This sounds overly simple, but the initial experiments on calculating absorption were done by
moving around seat cushions – simple, but effective.
Fabric-wrapped absorber panels are today’s high-tech equivalent to the seat cushions. Curtains,
blankets, carpets, and other soft materials will also help to reduce the acoustic energy of a space.
Treatments like diffusers help to reduce focused acoustic reflections by spreading the energy
around. When sound hits a surface that is not flat, it will cover the entire surface, bending
around the corners and curves, and then bounces off in different directions.
This reduces what we refer to as ‘specular’ reflections – or direct, mirror reflections – which are
responsible for slap echoes, ringing, and flutter.
However, some hard, reflective surfaces in the front of the room can be beneficial to help
reinforce acoustic sound sources, like speaking, singing, or acoustic instruments.
Treating corners with bass traps can help to reduce bass buildup, as well as corner reflections,
which can cause other clarity issues within the listening environment.
Don’t forget…look to the ceiling for rafters and other elements that cause sound to bounce
around and put some absorption up there.
Thanks to everyone who flooded our booth at the 2017 AES/NAB show last week at the Javits Convention Center in NY! We enjoyed all the enthusiasm of the attendees, and all of the conversations about projects, products, and acoustics!
If you kept your AES Dailies, you may have seen Jim and the Art Diffusor® Model D on Page 4 of the 2nd edition.
Enjoy the spinners!
(Note: Fidget Spinners are not an acoustic device… technically)
*spin* *spin* *spin* *spin* *spin*
Here at Acoustics First, we often receive inquiries from business owners who have moved into a commercial building shared with other tenants. Unsurprisingly, the most common acoustic issue is excessive sound transmission between neighboring businesses.
In commercial buildings with multiple tenants; such as outlet malls, office buildings and shopping centers, it is important to understand the nature of the neighboring businesses, especially ones directly next to, above or below an occupant. The following are categories of adjacent tenants with distinct acoustic environments which can disrupt or be disrupted by neighboring businesses.
Standard Adjacencies: These neighbors tend to be have soft to moderate ambient noise levels that range from about 40-75 dBA, which generally remain constant throughout their operating hours. This often includes low-moderate levels of background music or chatter that has no significant amounts of low bass frequencies. Some examples of these spaces would be standard retail, electronics, clothing, or shoe stores, coffee shops, grocery stores, department stores, call centers, or an office with an open layout. The requirements for sound isolation associated with these types of adjacencies are less stringent, so standard construction practices are generally acceptable.
Dynamic Adjacencies: These neighbors come in two categories “loud” and “soft”. The neighbor that would be categorized as “loud” would have an average of ambient noise levels above 75 dBA for long periods of time throughout operating hours. This level of noise sustained over long time periods will conceivably disrupt other neighbors that share adjoining walls. Some examples of these spaces are pre-schools or daycares, kennels (doggy day cares), high-sound-intensity fitness studios (cycling, aerobics, Zumba, CrossFit, etc.), bars/restaurants with loud or live music, recording studios and live music venues.
The dynamic neighbor that would be categorized as “soft” would have average ambient noise levels below 40dBA during operating hours. With this type of noise level, there is less tolerance for excessive noise coming from adjacent spaces/tenants. It’s important to minimize the overspill of noise to these spaces to avoid disturbing them. Some examples of these types of spaces would be doctor or law offices, spas/massage therapy, yoga studios, upscale retail, fine dining restaurants, libraries and book stores.
Dynamic adjacencies will usually need specialized acoustic treatment and/or construction in order to control excess noise transmission. If you are surrounded by dynamic neighbors (both loud and soft) or would classify your business as dynamic, you may have to apply fundamental construction and extensive acoustic treatment to control noise transmission. That said, even after taking these precautions, the noise transmission may not be reduced to tolerable levels. Some examples of these situations would be a high intensity fitness studio next to a yoga studio, a live music venue sharing a wall with an upscale restaurant, a Law Office above a Daycare or a recording studio under a book store. Avoid the hassle and expense of extensive construction by choosing your neighbors wisely!
So remember: when you are considering commercial locations for your business it is quite possible that you may encounter a number of these issues. It’s always best to design your space with the acoustic requirements of your neighbors in mind.