In case you haven’t seen it yet, The New York Times reports today that New York-area schoolkids have resorted to an unusual solution to cellphone bans. Apparently unaware of phones’ vibrate mode, the students have opted for an incredibly annoying ringtone pitched at 17,000 Hz. Theoretically, “adults” shouldn’t be able to hear that. (The real issue is middle-aged adults, an ironic choice in New York schools where many of the faculty are younger.) I also think that’s a liberal estimate of hearing loss; while most people lose some of their high-end hearing as they age, the numbers from the private security firm quoted in the article seem a little odd — 12,000 Hz for a 50-year-old? I hope not! (Better cover your ears on the subways, huh?)

A Ring Tone Meant to Fall on Deaf Ears [NYTimes.com; registration required and free story may expire]

The upshot of all of this is that there’s a free, if primitive, hearing test in the article (and presumably, all over the Web where these students are getting it). Hearing loss is a major problem; according to Aetna and the Harvard Medical School, 24% and 40% of adults over age 65 have difficulty hearing, and thirty percent of people over age 85 are deaf in at least one ear. For a better hearing test, here’s a free online example (I’m sure there are others online, and of course this does NOT substitute for a medical exam . . . nor can it measure just how annoying a kid with a cell phone can be):

Free Hearing Test

Anyone out there know what typical hearing loss figures are around middle age? (Lately, every time I write something some real experts show up out of nowhere, which is a pleasant experience!)

Hearing over the din of noise is something that humans do a lot better than computers. A new mathematical technique promises to provide highly accurate models of sound, even with broadband noise in the picture. Why does this matter, aside from mathematical curiosity? For one, better sonic analysis could mean more realistic models of instruments and more flexible sound editing tools, inspiring a new generation of music software.

From our friend kokorozashi:

‘In a recent issue of the Proceedings of the National Academy of Sciences, Marcelo Magnasco, professor and head of the Mathematical Physics Laboratory at Rockefeller University, has published a paper that may prove to be a sound-analysis breakthrough, featuring a mathematical method or “algorithmâ€Â? that’s far more nuanced at transforming sound into a visual representation than current methods. “This outperforms everything in the market as a general method of sound analysis,â€Â? Magnasco says. In fact, he notes, it may be the same type of method the brain actually uses.’

Full article:
New mathematical method provides better way to analyze noise [Physorg.com]

This certainly wouldn’t be the first time new algorithms yielded scientific advances and musical advances alike. Even the famed (or infamous) AutoTune plug-in benefits from data processing techniques used in oil exploration. (Lesson: it takes a lot of science to make Jessica Simpson sing in tune. Sorry, couldn’t resist.) Of course, the converse is true, too: better sound processing can be very useful to a broad range of sciences, because, well, sound is just about everywhere.

[Updated] Tom Duff has managed to hunt down the actual paper so you can get this straight from the source:

Sparse time-frequency representations,
Timothy J. Gardner and Marcelo O. Magnasco [Proceedings of the National Academy of Sciences]

While I wouldn’t normally say this of academic papers, it has really pretty pictures. (Seriously: visual renderings of the analyses not only illustrate the point, but also happen to look gorgeous.)

November 29 is the 205th birthday anniversary of Christian Doppler, the Austrian mathematician and physicist who hypothesized what’s now called the Doppler Effect. (You know, that effect when an ambulance or other fast-moving vehicle flies by and the perceived pitch changes.) That calls for Doppler trivia, astrophysics, audio software, and a drink.

In celebration, go check out the excellent Wikipedia page on the Doppler Effect, including one of my favorite Physics equations (while I wasn’t failing.) And if the idea isn’t sinking in, there are plenty of online demonstrations of why this effect occurs. (Science aside, I also recommend celebrating by imitating the sound of an English police car driving by in a movie. It works best if you simultaneously run by your significant other at high speeds.)

Because light can be a wave as well as a particle, the Doppler effect applies to light as well as sound. An increase in the observed wavelength of light emanating from a star is called a redshift. The principle is the same: as the source gets further from you, the wavelength (what it sound we perceive as pitch) shifts; in the case of a star, that translates to observed color.

Here’s the mind-bending caveat: there’s a misconception that Doppler-like redshifts are what allow astrophysicists to measure the expansion of the universe. Wrong! Why? Because it’s not the stars moving away from you (a la the Doppler ambulance); it’s the intervening space stretching, as per the understanding of General Relativity. There you go; if that hasn’t convinced you to go have a drink in honor of Christian Doppler, nothing will. (Heck, it’d probably convince him to have a few drinks, were he alive.)

Back to digital audio: If you want to reproduce the Doppler effect accurately, GRM Tools Classic has one of the best Doppler plug-ins I know of, available for both Pro Tools (RTAS/TDM) and VST. See the detailed review from Electronic Musician of a few years ago. GRM Tools is a great collection of plug-ins, but if you’re on Windows you can also opt for the much-cheaper GBP 15 a la carte option, Spacestation (VST). (Thanks, Afro!)

Or just go have that Dopplertini. (Anyone got a good recipe? I think it involves throwing the drink at high velocity . . .)

Two things most people don’t care to understand: physics and how the heck your car works. But you’re different. Why, you probably already know that phase cancellation occurs when a sound source is delayed slightly (by a real-world reflection, or in recording and mixing), so that two coherent waveforms of opposite phase are superimposes and cancel each other out. (Er, in plain english: one wave’s crests cancel out the other’s troughs and vice versa.)

Now, did you know this principle is what keeps your car’s exhaust from making a racket?

How Mufflers Work [Howstuffworks]

Basically, the muffler is a chamber designed to create lots of echoes, and thus lots of destructive interference.

See an extended discussion above, plus some variations on the design used in luxury automobiles (think active cancellation, as in noise-reducing headphones). And, of course, this is exactly what doesn’t happen when your remove a muffler and get that ear-splitting noise.

Got other candidates for acoustic science in the real world? Let me know!

While image technology has leaped forward, headphones and hearing aids still resemble 19th-Century tech. A show opening this week in London brings together designers seeking to change that. Ideas on view include glasses with built-in earphones that let you listen directionally to whatever you’re looking at, and “goldfish” earphones that repeat whatever someone said in the last 10 seconds — finally, I’ll be able to remember people’s names! My favorite: earbuds connected to a conductive strip so you can finally hear what your friends are saying at a bar. (Wait, maybe that’s not a good thing.)

See a great roundup of links from Régine at WWMNA, or browse a BBC News gallery.

Could selective hearing have possibilities for music? Absolutely — just ask my friend Joshua Fried, whose Headphone Sextet prompts vocalists with spoken cues for a variety of ingenious compositional configurations. And that’s just on the performer side; there are limitless possibilities for new listening environments, too.