|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
In Reply to: The beat goes on posted by Duke on July 27, 2002 at 10:52:06:
As a horn player a trumpet hitting 34Khz, I don't know about that. There must be some harmonic ossicllations within the brass of the instument or a recording artifact causing that. If not that dude has a magic set of chops.
Charles
Follow Ups:
A number of other instruments have harmonic spectrums that extend well into ultrasonics.Quoting from "There's Life Above 20 Kilohertz! A Survey of Musical Instrument Spectra to 102.4 KHz" by James Boyk of the California Institute of Technology:
"Harmonics of French horn can extend to above 90 kHz; trumpet, to above 80; violin and oboe, to above 40; and a cymbal crash shows no sign of running out of energy at 100 kHz."
Below is a link to Mr. Boyk's paper, which you might find interesting.
I don't think it's any news that the sound of some instruments have ultrasonic components although the detailed measurements are interesting. But, since no one can hear that high, what difference does it make?Kaoru and Shogo measured what appears to be intermodulation distortion in the loudspeaker between ultrasonic frequencies and frequencies in the audible range. They eliminated this by having the ultrasonic frequencies reproduced by separate speakers, at which point the audible effects disappeared. So, we have a ready explanation for the audible effects of ultra high frequency content: deficiencies in the reproducing equipment, not the recording.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
How about trying a comparison between a 20k-stone-walled recording with a 'no-holds-barred' one? (same performance of course).I haven't tried it before but it would be interesting to note on the magnitude of the sonic difference with and without the ultrasonic (convienently defined as > 20k) content, and how much it matters to the music that we are listening to. of course, terms like 'sonic difference' and 'how much it matters to the music' need to be very carefully/comprehensively defined.
Again my earlier comment: Some claim to be able to hear thru their teeth.. perhaps they can but the levels are REALLY low, perhaps even indistinguishable. Nice try.
I'm confused, Bare."BFD"?
"Nice try"??
And while we're on the subject, I never said anything about hearing through one's teeth.
Perhaps you don't buy my explanation of the phenomenon of "beats", so below I've posted a link to a site endorsed by the National Science Teachers Associaton.
By the way, a few years back Bob Carver was working on a device that involved a rather unique application of beats to "beam" a tightly-focused column of sound, using a 200,000 Hz carrier signal. He was able to re-create sound well within the audible spectrum entirely from ultrasonics. I searched the web but failed to come up with any specific reference to Carver's involvement. All I could find was a rather simplistic news article describing this technology, here:
http://www.abcnews.go.com/sections/scitech/CuttingEdge/cuttingedge010831.html
Basically, what I'm saying is: a) the "beat" phenomeon is real; b) ultrasonic overtones are real; and c) that ultrasonic overtones can generate beat signals within the audible range.
On the subjective front, a comparison of analog or SACD to redbook CD's demonstrates that the ear is indeed sensitive to things happening (or not happening) at frequencies theoretically above the range of human hearing.
Cheers,
Duke
This post is made possible by the generous support of people like you and our sponsors: