Tag Archives: sound

Unique noise features in populated areas

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People might generally think of cities as noisy. Amid this volume level, there can be unique noise phenomena in cities and populated areas. Here are two examples, starting with temperature inversion layers:

Photo by Anthony ud83dude42 on Pexels.com

Temperature inversion layers, like the one happening the night Tamblyn heard Billy Joel from her backyard, occur when cool air gets trapped underneath a layer of warm air.

The warm air prevents the cool air from rising, along with smog and sound. The sound waves bend away from the inversion layer and back to the ground, bouncing across further distances.

This is more likely to happen during the fall season, as well as during certain times of day.

The second example involves different kinds of surfaces:

Skyscrapers lining the street can amplify city sounds, according to acoustic consultant Scott Pfeiffer.

That’s because sound waves easily reflect off rigid, hard surfaces, like glass and brick, Pfeiffer said. Sounds bounce back and forth like the two sides of the street are playing tennis.

The end result is a sound “canyon,” which often creates an echo…

Trees, grass and other plant life act as natural absorbers and deflectors of sound.

Three thoughts in response:

  1. Does public noise matter less in an era where lots of people use AirPods and other headphones? People have used headphones for decades but the noise-cancelling features of today’s devices plus their ubiquity might mean more people are in their own soundscapes.
  2. If cities are greener in the future, particularly with more plants and greenery among the buildings, does this mean they would be quieter? Having fewer motorized vehicles could also help.
  3. It is common to think of cities in terms of neighborhoods or scenes. These are often defined with physical boundaries. Do sound boundaries roughly match these boundaries or are there different sonic neighborhoods in places?

The extra-real sound of the Olympics

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For those interested in sounds, this is a fascinating read about how the sound from the Olympics sounds so (hyper)real:

For the London Olympics, Baxter will deploy 350 mixers, 600 sound technicians, and 4,000 microphones at the London Olympics. Using all the modern sound technology they can get their hands on, they’ll shape your experience to sound like a lucid dream, a movie, of the real thing.

Let’s take archery. “After hearing the coverage in Barcelona at the ’92 Olympics, there were things that were missing. The easy things were there. The thud and the impact of the target — that’s a no brainer — and a little bit of the athlete as they’re getting ready,” Baxter says.

“But, it probably goes back to the movie Robin Hood, I have a memory of the sound and I have an expectation. So I was going, ‘What would be really really cool in archery to take it up a notch?’ And the obvious thing was the sound of the arrow going through the air to the target. The pfft-pfft-pfft type of sound. So we looked at this little thing, a boundary microphone, that would lay flat, it was flatter than a pack of cigarettes, and I put a little windshield on it, and I put it on the ground between the athlete and the target and it completely opened up the sound to something completely different.”

Just to walk through the logic: based on the sound of arrows in a fictional Kevin Costner movie, Baxter created the sonic experience of sitting between the archer and the target, something no live spectator could do.

Television is supposed be able to bring you live events (I know this doesn’t necessarily qualify for the Olympics) – I know I don’t think much about what technology this requires. But this article suggests the sound is even better than real: there is no one at the Olympic archery range who is even hearing what televisions viewers can hear.

Does this make watching all of those Olympics commercials a little more bearable?

Quick Review: How Music Works

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I like reading about music so I recently thought I would take a chance with a recently published book by British physicist John Powell: How Music Works: The Science and Psychology of Beautiful Sounds, From Beethoven to the Beatles. A few thoughts about this text which is intended for a general audience:

1. One of the key things this text tries to do is explain why we have the music structure today that we do. So he includes explanations about musical modes that developed in history (of which we use two today, one the major scale and one the minor scale) and how instruments, like the harp, can be configured to produce notes.

2. One of the most interesting things to me in this book was the fact that agreement about modern notes didn’t happen until a conference in 1939. Before that, an A in Leipzig and an A in Paris might not be the same sound. It wasn’t until this conference that a particular frequency (A = 440) was set so that all instruments could be set to the same pitches. And even then, Powell suggests choosing this particular frequency occurred not because it is a better sound but rather because it is somewhere in the middle and seemed good. To think that the sounds we know today are really a social construction is intriguing.

3. There are number of little discussions that a reader might find interesting about perfect pitch, the physics of sound versus noise, how we can rate sound intensity (and he does not like the decibel system), and whether there are certain keys that are happier or sadder (the conclusion: no, they all share the same patterns of notes).

4. While I enjoyed a number of these shorter discussions, I wonder whether someone with limited or no musical knowledge could take much from this book. At various points, Powell suggests one doesn’t need to know how to play or read music to understand the discussions but I think it would be difficult. To his credit, Powell does suggest that anyone of any age can learn music – yes, it takes time (and he invokes Gladwell’s rule of 10,000 hours needed for expertise) but he suggests the idea that some people are musical and others are not does not hold water.

Overall, a book with some interesting points. The discussion bogs down in places and may be difficult for those with little music knowledge but it is an interesting start in considering how music is made.