A Bit of Acoustical Treatment Can Go a Long Way

Reverberation is the great equalizer. It can make great music sound the same as less-stellar counterparts. It can make a great speech in a large hall sound the same as one that is devoid of content, and it can distract anyone from the task at hand.

And of course reverberation is like good wine – too much is as bad as too little.

The Canadian government recently announced that they were going to renovate one of their old office buildings to house more government officials in downtown Ottawa. What caught the news is that they were going to be spending $131,000 to add acoustic paneling to the walls.  (What the news missed is that they also paid $5,000 for some coat hooks!)  While $131,000 sounds like a lot, it is a small price to pay to make this old building accessible for speech communication.

Courtesy of Broadmead Hearing Clinic

It’s easy to make a room more live – to increase the reverberation – and one does not need to spend $131,000. One can simply erect reflective structures such as mirrors, change curtains to ones that less absorbent, and remove the 1960s shag carpeting.  One does not need an acoustical engineer to figure this one out.

But reducing the reverberation may require some professional help. 

There are some simple things to do until the acoustical engineer does come. If it’s a school class room, placing 3-D art on the walls will certainly help, leaving the doors open to the cloak room at the back of the room will deaden unwanted reflections, and the use of heavier-than-normal window coverings or drapes will also help. Reducing the sources of noise will also help; for example, tennis balls on the legs of the students’ chairs will reduce the scraping sound. Reducing noise will reduce the sound that ultimately will be reflected.

And it doesn’t need to be expensive.  The erection of a series of acoustic panels on one wall can be less than $300 and will significantly increase the “warmth” of any room.

Courtesy of Acousticmac.com

However, once the acoustical engineer does come in, some amazing things can be done to optimize the listening in any room. 

Stucco-like spray can be applied to the ceiling of school gymnasiums, or large halls. The irregular surface serves to reduce the shorter wavelength, high frequency reflection.  Acoustic banners suspended from the ceilings can be both informative and colorful.  We see this in many airport arrival and departure halls – informative signs that also (surreptitiously) serve to reduce echoes.

In many cases, we don’t even know that an acoustical engineer has been there. Out of sight; out of mind. But acoustical engineers are one of the most important people in building design and the subtlety of their work sometimes causes us to forget that they were even there.

Audiology counselling rooms tend to be on the small side so one would not normally be concerned about reverberation. The hearing health care professional is usually within several feet of the hard of hearing listener, and the room is typically away from noisy hallways and waiting rooms.  But even the use of some acoustic paneling on the walls, can increase the warmth of the sound by reducing the sound reflections- and they can add to the beauty of the room.



About Marshall Chasin

Marshall Chasin, AuD, is a clinical and research audiologist who has a special interest in the prevention of hearing loss for musicians, as well as the treatment of those who have hearing loss. I have other special interests such as clarinet and karate, but those may come out in the blog over time.