I've made a device in my connected device class. I want to use this portable device to measure the sound level around me every day. The device connects to the network and uploads readings whenever the sound level exceeds 80dB. The reason why I chose 80 is based on CDC(Centers for Disease Control and Prevention)'s data chart.
According to the chart, noises under 80 dB show no significant hearing damage no matter the exposure time to the noise. However, when noises exceed 80dB, damage to hearing will occur from 2 hours to less than 2 minutes when it reaches 110 dB.
I've bought my device with me through my trip to Philadelphia, where I was utilizing different methods of transportation including subway, taxi, and train, as well as walking on the street.
The first readings appeared when I was in my Uber to Penn Station. During the 25 minutes trip, the readings averaged 90 dB and peaked 105 dB, which is surprisingly loud. I was talking with my girlfriend during the ride and none of us had any problem hearing or understanding each other. Without any supporting evidence, my hypothesis is that there are two reasons why the noise is less noticeable. First, the road noise is relatively consistent. I and my girlfriend potentially get used to the sound where our ears did the "filtering" for us. Secondly, I suspect it also has to do with the frequency of the noise, as most road noises are heavily concentrated on the lower end. When people communicate with each other, the higher frequencies play a more important role in recognizing certain vocabularies and emotions, and therefore, aren't affected as much if the noises are only at the lower frequencies.
In fact, the readings in Philadelphia's monorail sort of demonstrated my hypothesis. Also peaked at 104 dB, we experiences a much more disturbing feeling while in the station, much similar to what we experienced in the MTA. When the train brakes and accelerates, there's always a high pitch sound that makes me want to cover my ears. Although the peak seemed to last shorter than the ones captured in Uber, they do feel more intrusive and unbearing.
Philadelphia's street isn't necessarily quiet either. While walking on the street, I get a reading of around 85-90 dB from every 30 seconds to a few minutes. It won't hurt your hearings, but it's definitely unpleasant when you are trying to enjoy a casual walk.
Another surprising reading, or to say "none" reading is when we were in restaurants. Although it was very crowded, the noise level rarely exceeds 80 dB, which doesn't really line up with my impression. Whenever entering a restaurant, I always feel overwhelmed by the crowd, yet the reading tells differently. I was a bit confused by this result while on site, and in fact tested the device by shouting at it just to see if there was a malfunction. It turned out that the reading wasn't wrong. I suspect it also has to do with the frequency: Human voices are centered around a range of frequencies and most of us probably experienced this in real life that when two people are talking simultaneously, none of them could be understood. Therefore, although experience difficulties hearing each other, I and my girlfriend aren't exposed to hearing-damaging noises.
Throughout this project, I was able to understand my environment more deeply from the perspective of the noise of sound level. Realizing my biased opinions on certain locations and scenarios was really valuable for me.