How do you block noise from fireworks?
They might be fun to look at, but loud noise from fireworks can be a huge stressor for pets and their human companions. And it’s also big business for companies that sell “relaxing” products like Feliway or puppy edibles to keep your furry companions calm during noisy holidays like the 4th of July or New Year’s Eve.
This 4th of July, I decided to measure the fireworks noise through some of the windows in my home. Fireworks boomed continuously across the entire city until at least midnight. I measured both the decibels and the frequency ranges from these locations:
- an open window (with double-paned glass)
- the same double-paned window again when it was closed
- a double-paned window with an extra layer of 1/4″ plexiglass across it, and
- another double-paned window in a different room that used QuietRock (sound-dampened) drywall
You can watch a short video of the tests here:
Most of the results didn’t surprise me, but it was satisfying to collect the actual data. Even though the window with the extra plexiglass was in the same room as the window that didn’t have any plexiglass, the measurements indicated a small reduction in the decibel level with the extra plexiglass. And more importantly, that sheet of plexiglass significantly reduced the mid-range and higher frequencies, so that most of the remaining frequencies were below 100 Hertz.
Soundproofist’s fireworks noise test results at a glance
The fireworks were not going off directly on my street. Many of them were at least 1/4 mile away, or even farther. However, the clouds in the nighttime atmosphere helped the sound travel all over the city. If the fireworks had been closer to my home (within a block or two), the results would have been different. The window insert might have been less effective, like when loud cars drive just below.
Low-frequency noise (bass) travels a longer distance and has longer sound waves. Lower frequencies can penetrate solid surfaces more than mid-and higher-range frequencies. So it’s no surprise that the lowest frequencies (sometimes as low as 29 Hertz) were still measurable by the plexiglass window insert.
In summary:
- An extra sheet of plexiglass across a window can be effective at lowering some of the noise from distant fireworks
- Plexiglass alone might not be very effective if the fireworks noise is nearby, or if you have thin wall construction
- The plexiglass lowers the volume and cuts out many of the mid-range frequencies, but low frequency noise can still come through
- The QuietRock walls in the rear room helped to lower the decibels compared to all the tests in the front room, even without extra plexiglass on the window — but the untreated rear window still let in a wider range of noise
- QuietRock (and/or double drywall) can be effective against distant low-frequency noise, and might be more effective if combined with extra plexiglass on the windows in that room.
More resources:
- Putting a window “insert” outside the window frame: Some learnings I made, described in this video
- The Window Experts (video): although they sell windows, they explain STC pretty well
- Bob Vila: “5 Smart Tips for Soundproofing Windows“