The Realm of Effective Acoustics Part 2: When Armchair Acousticians Go Viral

The Realm of Effective Acoustics Part 2: When Armchair Acousticians Go Viral

Enter the realm of effective acoustics. Here we will dispel common misconceptions and take a look at the proper way to solve problems related to noise and sound, from making a room sound better to controlling and measuring noise.

In Part 1 we met the armchair acoustician and discussed the differences between sound isolation and room acoustics. In Part 2, we’ll continue to look at sound isolation and room acoustics, but first, let’s unpack the perils of stuffing a space with insulation.


Infotainment for the Masses

The internet is full of explainer videos. Whatever the topic, from mosquito bites to geographic boundaries, some expert somewhere is enlightening the World Wide Web with a fun-yet-comprehensive three-minute video.

Most of these videos fall into the category of infotainment and feature experiments designed to highlight noticeable changes. While the results can be impressive, they don’t always provide solutions to real problems.

For example, in a video that shows how batt insulation can control sound, an expert (an armchair acoustician, perhaps?) places a beeping device in a box and covers it with layer after layer of batt insulation. The expert records the sound levels outside the box and viewers can hear and see how each layer adds additional sound control.

The experiment seems cool, but it lacks rigour.

  • First, nobody controls noise this way. That much batt insulation could create a fire hazard!
  • Second, the most effective acoustical fixes are, simply put, not that exciting. No one wants a video of an acoustician at their desk, reviewing shop drawings, drafting recommendations, and sending emails.
  • Third, an acoustician’s recommendations, when applied, usually result in subtle changes. While these upgrades might be necessary to ensure compliance or improve the usability of space, they don’t make for riveting cinema.


More on Sound Isolation and Room Acoustics

Since stuffing a wall with insulation isn’t the best way to isolate noise between two rooms, what about installing sound absorptive material in the room itself?

As we covered last time, when it comes to meaningfully addressing a noise problem between two rooms, adding material that is intended for reverberation control won’t result in a noticeable difference in sound isolation. Really, the best solution for sound isolation is to add mass to the partition.

Treating a space with sound-absorptive material, however, will make it ideal for studying, reading, or having an intimate conversation. On the flip side, an acoustically “dead” space, that is, one with shorter reverberation times, won’t invoke the party animal in any of us.

So if a party is what you’re after, choose a lively, reverberant room, but do so with caution: The conditions that make a space sound fun can also allow noise to accumulate. This noise buildup is known as the cocktail party effect. You’ll know it’s at work when partygoers begin raising their voices to be heard. (The shouting has nothing to do with the cocktails, though.)

The cocktail party effect definitely adds to the loudness of a space (although, again, not to the sound isolation). Thankfully, most residential spaces are too small to be susceptible to the cocktail party effect. The larger the space, the greater the potential for noise buildup.

Most event spaces have been designed to control reverberation times according to their function. For those that haven’t, adding absorptive treatment can be an effective way to improve how a space sounds—even in multi-use spaces.

If you have a room that might benefit from carefully designed acoustical upgrades or need some professional recommendations for controlling sound between rooms, we’d love to hear from you!

We hope you are enjoying your journey through the realm of effective acoustics. In Part 3 we’ll take a look at the myth of the concert noise measurement app.

Written by Joonas Niinivaara

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