Today's weather: High = 25 Low = 18
Sunny and beginning the warm-up to an impending heat wave this week. It'll soon reach 35 degrees again
Having tried the white noise generator for 3 nights now, it has been quite successful. I'm now going to cross-post this information to the online expat forums in China which have recurring threads where people complain about the noise. I'm also going to bring this experiment into the classroom and use it for a math review lesson on logarithms.
It was all inspired by a powerful air-conditioner in Bangkok that pumped out cool air and white noise at the same time, -thus allowing for multiple days and weeks of restful sleeps while previously living in that large and noisy city. It was then a simple matter of trying to replicate the noise from the air-conditioner in Shanghai without actually having that machine over here. Using a few pieces of basic equipment, the scientific method, and a few tweaks, the experiment is pretty much done.
While it may seem that the Shanghainese are obsessed with noise, and they are happy to live with this racket every day, the government is actually taking the noise pollution problem rather seriously. The government has made some good strides in recent years, particularly the installation of noise barriers along busy highways and railway lines. Also, everywhere you go on busy intersections they have decibel boards set up to record the ambient noise and display a red warning when it exceeds 70dB. They compare with previous years and find that the ambient noise levels are slowing decreasing over time.
The way the decibel scale works is that it is relative. Actually, all measurement scales are relative with some calibration to a standard, for example, 0C is when water freezes, etc. Decibels are 1/10 of a bel, named after Alexander Graham Bell. The 0dB is calibrated to a 'standard threshold of hearing', whatever sound intensity that is.
Going back to the last post, if a sound souce (i.e. train) is 100m away, the intensity where I hear it is 0.0001 times less compared to the source. Using logarithms, that is 4 bels less, or 40dB less. So if the train has a 110dB sound at the source, and the Shanghai government can reduce it to 85dB using noise barriers, then I'll pick up 45dB at my location. Using the computer, that's what I'll need to set the noise generator to match at.
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