чё претихли?

...I was referred to a research project conducted at CalTech about 15 years ago. The resulting paper is titled:

There’s Life Above 20 Kilohertz!
A Survey of Musical Instrument Spectra to 102.4 KHz
James Boyk
California Institute of Technology

You can check out the paper by clicking here.

Here’s the abstract:

“At least one member of each instrument family (strings, woodwinds, brass and percussion) produces energy to 40 kHz or above, and the spectra of some instruments reach this work’s measurement limit of 102.4 kHz. Harmonics of muted trumpet extend to 80 kHz; violin and oboe, to above 40 kHz; and a cymbal crash was still strong at 100 kHz. In these particular examples, the proportion of energy above 20 kHz is, for the muted trumpet, 2 percent; violin, 0.04 percent; oboe, 0.01 percent; and cymbals, 40 percent. Instruments surveyed are trumpet with Harmon (“wah-wah”) and straight mutes; French horn muted, unmuted and bell up; violin sul ponticello and double-stopped; oboe; claves; triangle; a drum rimshot; crash cymbals; piano; jangling keys; and sibilant speech. A discussion of the significance of these results describes others’ work on perception of air- and bone-conducted ultrasound; and points out that even if ultrasound be [is] taken as having no effect on perception of live sound, yet its presence may still pose a problem to the audio equipment designer and recording engineer.”

I applaud the author on establishing that musical partials extend to well above the accepted upper limit of human hearing. It’s clear that we’re exposed to a lot of ultrasonic frequencies during a live performance of a symphony orchestra. Of course, the distances involved in this test are not like being in Carnegie Hall but it reveals something that I’ve known for a long time. Music doesn’t stop at 20 kHz…so why should our recording and reproduction systems?©

https://www.realhd-audio.com/?p=2465