We decided to run informal experiment to see how loud a movie theater can be and if a viewing a movie could cause temporary hearing loss. The results were surprising.
Why A Movie?
The greatest risk to our hearing in North America is noise induced hearing loss (NIHL). Unknowingly our leisure time activities can all too often be the reason for over exposure to loud noises. NIHL most commonly occurs by repeated exposure to high noise levels over long periods of time. The slow, subtle loss of hearing is insidious and will often go unnoticed until it becomes an obvious problem.
Noise induced hearing loss is 100% preventable and permanent.
Step 1: we performed a hearing test on our moviegoer to verify that their hearing was “normal”.
Step 2: an hour later we sent our movie fan off to see the movie Logan (2017) at the Scotiabank Theatre Winnipeg (Formerly Silver City Polo Park) where they would take sound level measurements periodically through the movie.
Step 3: immediately after the movie our movie fan repeated their hearing test with a different technician.
Step 4: we then compared the results between the two audiograms.
The human voice is typically heard at a range of frequencies from 250Hz to 4000 Hz
Generally speaking, noise induced hearing loss affects the upper frequencies more so than the lower frequencies. The maximum hearing loss recorded was 10 dB in the right ear at a low 250 Hz and again at 4000 Hz. Although we expected to see a few minor indicators of hearing loss, 10 dB is significant. Equally surprising was the almost uniform 5 dB loss in the left ear with zero loss at 1000 Hz and 8000 Hz.
With a running time of just 2 hours and 21 minutes the movie Logan did not seem to represent a sufficiently long period of time with high noise levels to have these results. With the majority, the movie’s sound levels in the mid to high 80 dB range and the loudest action scenes reaching 96.1 dB for only a few minutes, our informal experiment serves to reinforce the idea that we are often exposed to much louder noise levels than what we might perceive to be safe.
Recent studies have shown that our hearing has a built-in mechanism to help deal with excessively loud environments. Often short-term noise induced hearing loss like this is shown to be temporary when a hearing test is performed just one day later. However, the cumulative effect of loud events has been shown to generate long-term hearing loss.
In the end, do we think that a couple movies a month are going to have a profound negative effect on your hearing?
A couple of movies a month may not cause noise induced hearing loss, but when you consider a lifetime of activities such as movies, concerts or even using a lawn mower these noisy activities can add up to more damage than we realize.
Let us know what you think - leave a comment!
To hear what you’ve been missing, call the Polo Park Hearing Centre Monday to Friday between 9 a.m. and 5:30 p.m. and Saturday between 10 a.m. and 2 p.m. (204) 788-1083