jm + noise   7

The Loudest Sound Ever Heard
The Krakatoa explosion registered 172 decibels at 100 miles from the source. This is so astonishingly loud, that it’s inching up against the limits of what we mean by “sound.”
When you hum a note or speak a word, you’re wiggling air molecules back and forth dozens or hundreds of times per second, causing the air pressure to be low in some places and high in other places. The louder the sound, the more intense these wiggles, and the larger the fluctuations in air pressure. But there’s a limit to how loud a sound can get. At some point, the fluctuations in air pressure are so large that the low pressure regions hit zero pressure—a vacuum—and you can’t get any lower than that. This limit happens to be about 194 decibels for a sound in Earth’s atmosphere. Any louder, and the sound is no longer just passing through the air, it’s actually pushing the air along with it, creating a pressurized burst of moving air known as a shock wave.[...]

Amazingly, for as many as 5 days after the explosion, weather stations in 50 cities around the globe observed this unprecedented spike in pressure re-occuring like clockwork, approximately every 34 hours. That is roughly how long it takes sound to travel around the entire planet.
sound  shockwaves  earth  krakatoa  disasters  volcanos  eruptions  noise  decibels 
17 days ago by jm
How Good Is Spotify's Audio Quality? · Baron Schwartz's Website
Various streaming services (Spotify) use lossy formats (Ogg Vorbis); various audio-casting devices (Chromecast) use other lossy formats (AAC). Crappy audio quality issues ensue.
chromecast  ogg-vorbis  aac  audio  lossy-encoding  compression  noise  fail  spotify 
march 2018 by jm
DST breaks everything
LOL as DST bug uncovers spurious automated noise complaints:
In January last year the airport unearthed a scheme whereby campaigners were using automated software to generate complaints against the airport. Officials caught out the set-up when the two anti-Heathrow enthusiasts forgot to take into account the hour going back in October, and began complaining about flights that had not yet taken off or arrived.
bugs  dst  daylight-savings-time  funny  heathrow  complaints  automation  noise 
november 2016 by jm
_Airport Noise NIMBYism: An Empirical Investigation_
'Generally, a very small number of people account for a disproportionately high share of the total number
of noise complaints. In 2015, for example, 6,852 of the 8,760 complaints submitted to Ronald Reagan
Washington National Airport originated from one residence in the affluent Foxhall neighborhood of
northwest Washington, DC. The residents of that particular house called Reagan National to express irritation about aircraft noise an average of almost 19 times per day during 2015.'

Somebody needs help.
airports  noise  nimby  nimbyism  complaints  dc 
october 2016 by jm
Riding with the Stars: Passenger Privacy in the NYC Taxicab Dataset
A practical demo of "differential privacy" -- allowing public data dumps to happen without leaking privacy, using Laplace noise addition
differential-privacy  privacy  leaks  public-data  open-data  data  nyc  taxis  laplace  noise  randomness 
september 2014 by jm
Universal Music Group adding audible "watermarks"
including on paid-for, losslessly-compressed digital audio music files:
Why isn't UMG's watermark talked about more? Maybe people think the audio quality problems are due to some kind of lossy compression, as I did, and ignore it completely, or blame the streaming service/distributor. The problem here is that the UMG watermark degrades the audio to about the equivalent of a 96 kbit MP3. My guess is that if consumers were informed about what is going on, they would care. Especially those who pay full retail price for digital downloads advertised as lossless audio.
lame  audio  drm  media  music  umg  universal  watermarks  noise  consumer  mp3 
may 2013 by jm
That mysterious J
"in e-mail from Microsoft employees, you may find a stray J [...] The J started out its life as a smiley-face. The WingDings font puts a smiley face where the letter J goes. [...] As the message travels from machine to machine, the font formatting may get lost or mangled, resulting in the letter J appearing when a smiley face was intended." aha! mystery solved. Amazon is full of mysterious "J"s in emails, and now I know why
amazon  j  letters  wingdings  microsoft  spoor  fonts  noise  from delicious
november 2010 by jm

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