Wikipedia:Reference desk/Archives/Science/2018 August 3

= August 3 =

Material that generates ultrasound, and not sound, when hit
Could a ultrasound drum exists? That is, when hit, it would generate ultrasound and not sound? Could any ultrasound (silent for humans) instrument exist? Does this strike a chord to anyone?--Doroletho (talk) 12:02, 3 August 2018 (UTC)
 * A Dog whistle is an ultrasound instrument. ←Baseball Bugs What's up, Doc? carrots→ 12:10, 3 August 2018 (UTC)
 * A drum is a membranophone, and there's no reason why one can not be tuned to sounds higher pitched than humans can perceive. The tuning of drums would obey a two-dimensional analogue of Mersenne's laws (which describe the tuning of strings); that is you can alter the diameter, thickness, and tension on the drum head and create any arbitrarily high sound.  The problem with doing this with drums is that drums have a very broad musical "bandwidth"; so while you could perhaps create a drum which had significant sound in the ultrasound range would still have some frequency space in the audible range.  For an instrument like a whistle, the bandwidth is MUCH tighter, so you only get a narrow band of frequencies.  -- Jayron 32 18:12, 3 August 2018 (UTC)
 * And an old Guinness said the lowest musical instrument is a 64 foot tall organ pipe in Atlantic City that makes 8 Hertz. Sagittarian Milky Way (talk) 19:44, 3 August 2018 (UTC)
 * That's infrasound. Abductive  (reasoning) 04:42, 4 August 2018 (UTC)


 * Jangling a bunch of keys generates plenty of ultrasound, but some audible sound too.
 * Some depends on your definition of "ultrasound". Children can hear frequencies which adults no longer can. Some of the first TV remotes, the 'Zenith Space Command' from the 1950s, used this range of near-ultrasound, generated with by a purely mechanical remote control with mechanical reeds like a thumb piano, and a frequency-sensitive receiver on the set. Andy Dingley (talk) 20:55, 3 August 2018 (UTC)


 * Hitting a drum is like subjecting it to an Impulse function, which will then yield an Impulse response. Since the original impulse contains all frequencies, it will include audible sound requencies, so you will need a structure than can act like a high pass filter to only allow ultrasonic frequencies. You will need a mechanical Audio filter. If you can arrange to beat you drum at a rate of 20 kHz or higher you should be able to achieve what you want. Graeme Bartlett (talk) 05:21, 4 August 2018 (UTC)
 * Or make 2,001 copies of an mp3 of an AK47 and start them at 1/20010th second intervals? Sagittarian Milky Way (talk) 05:58, 4 August 2018 (UTC)


 * Pedantry: MP3, as with any lossy audio codec, removes various parts of the audio signal that humans don't notice significantly. However, this might cause issues in something like that. It would be ideal to use a lossless audio recording. --47.146.63.87 (talk) 09:14, 4 August 2018 (UTC)
 * Actually, the chopping of sound from cymbals seems like a good thing. My personal opinion has been that the "ultrasound" of the cymbals so overwhelms the other instruments in a rock performance as to completely overwhelm them in a live concert, while the MP3 will balance them.  Barring that, a strategic pillar might be an option (ultrasound is pretty line of sight).   at least confirms they go up into "ultrasound". Wnt (talk) 21:51, 5 August 2018 (UTC)
 * Ultrasound avoidance is an antibat tactic known to be evolved by insects to escape from predators that echolocate using ultrasound. Evolution of a similar ability in humans, as Wnt's report suggests, is an unexpected byproduct of Rock concerts. During the time it will take to discover whether the ability is inheritable (readers are probably aware of some popular methods) a practical step against concert-induced SHL or NHL is to invest in Earplugs which may be of the passive or active In-ear monitor kind. They won't help much after Tinnitus sets in. DroneB (talk) 13:25, 6 August 2018 (UTC)