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SHATTERING MYTHS

In the matter of glass-shattering vocalism, Cecil seems to have been led astray by Gunter Grass's fictional tin drummer, Oskar [May 11]. In fact, there is no authentic record of glass being broken by the unamplified human voice. Dorothy Caruso categorically denied rumors that her late husband had accomplished the feat; a fortiori it was beyond Gigli's comparatively feeble instrument. Practically speaking, there are reasons to believe the thing impossible, and without going into technical detail, the following are among them: (1) Glass is simply much too strong. Try shattering a wine glass in your (gloved) fingers. Not easy. Now imagine doing the same with the puny little bands of your vocal cords. (2) Coupling acoustic energy from larynx-to-air-to-glass is highly inefficient due to large impedance mismatches; by contrast, marching troops couple very efficiently to bridge platforms. (3) In glass shattering attempts, resonance or no resonance, the glass structure finds other ways to dissipate energy short of fracturing. Remember the playground swing in which successive small but well-timed swings sent your sister sailing higher and higher? And the tales of going "over the top" when the process went critical? Alas! it never happened, because other dynamic processes supervened ("Gee, Mom, we were just playing") before the longed-for loop could occur. --Timon, Dallas

A fortiori? Supervened? Boy, I see I wasn't the only one to get a Word-A-Day calendar for Christmas. As for glasses, let's clarify one thing: it is certainly possible to shatter glasses with the amplified human voice. The folks at the Memtek company in Fort Worth, Texas, which makes Memorex recording tape, do it all the time for sales demonstrations and whatnot. (You'll remember that Memorex used to run those TV commercials showing Ella Fitzgerald and others breaking glasses with their voices.) What's more, they do it pretty much the way I described: they go out and get a drinking glass with high lead content, tunk it with a rubber mallet to make it ring, then read the frequency on an analyzer. Then they get a singer to sing the same note (typically F above middle C), amplify it to maybe 92, 94 decibels, and with luck you get glass shrapnellini. Memorex technicians using a strobe have found that prior to the break the sound causes the rim of the glass to deflect as much as a quarter inch. (I get this from Rick Needham, engineering manager, lest you think I am making this up.)

Your beef is that I suggested this could be done with the unamplified human voice. I'll grant I haven't been able to turn up a documented instance of this, but it seems subsidiary to my main point, which is that you can shatter glasses with sound, and furthermore that the human voice, which can generate a relatively pure tone, is well suited to this purpose. Furthermore, none of the technical people I spoke to about this seemed to think doing it by voice alone was completely impossible. Admittedly 90-plus decibels is pretty damn loud, but one of the reasons the Memtek folks crank it up that much is that they're using an inexpensive ($7) glass rather than fine crystal, which is more fragile. So let's not be such a font of negativity, Timsy. It's the can-do attitude that has made this country great.

PROOF THAT THE ALIENS HAVE LANDED!

Aliens do create "crop circles" [April 20]. Specifically, to give indications of their presence here, according to my reliable sources (several, mostly channeled independently). Despite massive official denials and cover-ups, this planet's been crawling in ETs since we shook up this sector of the galaxy splitting atoms. Why "answer" questions to which you don't know the answers? --J. Jones, New York City

The more letters I get like this, J., the more I start to think you're right.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

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