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For anyone new to the world of acoustics, there is a multitude of terms, coefficients and numbers that are thrown around. This flood of information can seem intimidating, especially to beginners. In this series, acoustician Cameron Girard of Acoustics First® hopes to help you distinguish between what’s useful and what’s not.
Part 3: Perception of Volume
Our ears are wonderful and intricate tools that many of us take for granted. It is very important to understand the idiosyncrasies of our hearing when considering the effect a certain acoustic treatment will make. For starters, let’s take a look at how our ears interpret volume.
Volume (Sound Intensity)
Sound levels (i.e. how loud something is) are typically expressed in decibels (dB). Human hearing ranges from 0dB (threshold of hearing) to 130dB (threshold of pain). The following chart displays common sound sources and their typical dB level.
Do two candles really burn twice as bright?
If one trombonist plays at 70dB, how much louder would it be if another trombonist started playing at 70dB? One might assume that the two trombonists combined would play at 140 dB, but this is not the case. Since decibels are logarithmic values, they cannot be combined by normal algebraic addition. When two sources at the same level play, 3dB should be added to the value to find the combined sound level. So in adding another trombonist, you would really only increase the level to 73dB, a much smaller jump than expected.
“Doubling” the amount of players will double the acoustic power, but what do we actually hear? The loudness perception table shown below displays how these decibel changes are actually perceived by the listener.
Loudness Perception Table
|Change of Level||Approx. Perceived Difference||Volume Gain Factor||Acoustic Power Gain Factor|
|+10dB||“twice as loud”||2.000||10.000|
|– 3dB||“noticeably quieter”||0.812||0.500|
|– 6dB||“significantly less loud/noisy”||0.660||0.250|
|– 10dB||“half as loud”||0.500||0.100|
*Chart Courtesy of David Eagan’s Architectural Acoustics (New York: McGraw-Hill, 1988),
As you can see, doubling the acoustic power (a change of 3dB) would be “noticeable” but not “significant”. It would take a jump of 10dB to make something sound twice as loud. Keep this chart in mind when reviewing acoustic predictions, particularly those that that pertain to noise reduction/control and sound isolation.
Here’s a nice example of a 3D rendering vs. real life. This 3D model was created by our acoustic analyst, Cameron Girard, for one of our church clients. We think the final results turned out fantastic!
Sonora® Acoustical Wall Panels are always a great choice where excessive reverb and diminished speech intelligibility are an issue.
Acoustics First® Art Diffusor® Model D spotted in music video for Usher’s “Rivals” featuring Future…
Watch the video on YouTube here… Usher – “Rivals” Featuring Future.
Acoustics First® is hankering to announce the first products made with our newly developed AuraGELL-O™ Compound. First realized by Peter Cooper and patented in 1845, this Biosynthesized Bifractive Polyamide has a “sweetness” when combined with our Diffusive Biomass Technology. AuraGell-O™ is a Bio-Polyamide compound which exhibits Bifractive properties, doubling the potency of the Biomass Diffuser Technology by carving the wave in two, thereby creating a phase cancelling stream which functions as a frequency tuned absorber.
The AuraGELL-O™ Infra-Red dissolves low-frequencies, while AuraGELL-O™ In-LIME absorbs the mid-band frequencies (Acoustics First® is cooking up AuraGELL-O™ Ultra-Violet for high frequencies).
Available in AuraGELL-O™ Barrel and Pyramid formats, you get the benefits of classic diffuser styling with the added bonus of the AuraGELL-O™ Biosynthesized Bifractive Polyamide with Biomass Diffuser Technology.
“We loved our AuraGELL-O™ Barrels so much – we went back for seconds!” – Angelo LeMonjello
Call Acoustics First® and get your AuraGELL-O™ Barrels and Pyramids today – because by tomorrow, they will all be devoured!
Update: Due to an outbreak of AuraGELL-O™ weevils, and massive consumer demand, we regret to inform you that this was an April Fool’s joke.
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.