February 2024 Newsletter: Wading the Acoustical Waters

Acoustics is a field that is difficult to understand.  Subtle distinctions between metrics, technical jargon, and non-arithmetic mathematics create a perfect storm of confusion for those who don’t normally swim the waters.  There are common malapropisms that we hear time and time again, which we would like to put to rest.  From the existence of silence to the use of the term “soundproofing,” read on to learn how to avoid misusing these words.

If you’ve ever been camping before, you’ll likely know the experience of laying down to sleep and realizing just how quiet your surroundings are. However, even in the middle of a forest, the wind causes the leaves to rustle, crickets chirp, and our own breath fills the soundscape. Silence is defined as “the complete absence of sound.” What many would quantify as silence is actually just a very low sound level. According to the US National Park Service, the forest described above would have an ambient sound level of between 20-35 dBA depending greatly on its proximity to populated cities and roads. This is still well above the threshold of human hearing, which is defined as 0 dB. Even below this threshold there is still sound, it’s just imperceptible to the human ear. Since sound is transmitted by the movement of particles in the air or in other materials, absolute silence would require the movement of all particles to stop. In other words, silence does not actually exist. At least not outside of a perfect vacuum.

The most commonly misused word in regard to acoustics is “soundproofing.” Acousticians tend to get annoyed at the usage and popularity of the term, but why? The suffix “-proof” means to protect against or make impervious to, and being impervious to sound is not possible. Sound can be reduced in energy whether its absorbed or blocked, but nothing will ever be resistant to all sound. Furthermore, the term is ambiguous and often misused by referring it to sound absorption and sound isolation, which are two entirely independent concepts.

By doing an internet search for the word soundproofing, everything including the kitchen sink comes up. One of the more common hits references soundproofing to surface applied acoustically absorptive panels. When utilized effectively, wall panels like fiberglass, felt, or mineral wool, help reduce reflected sound within a space; they do not however, make your room impervious to sound. In addition to acoustically absorptive panels, the internet search will bring up materials related to isolation between rooms or from outside to inside including curtains, mass loaded vinyl, and blown-in insulation. All of these materials have their uses, but it sometimes takes an expert to sort through the overload of internet information.

To recap, silence does not exist, soundproof is not a thing, and absorption ≠ isolation. We’ll help you sort through what does what as there is no one size fits all solution for acoustics, which is a good reason to ❤️ your local acoustical consultants!

March 2024 Newsletter: To be or not to be... Intelligible
SenSV Team Visits Mispro