pauln Posted July 21, 2006 Share Posted July 21, 2006 There's Life Above 20 Kilohertz! A Survey of Musical Instrument Spectra to 102.4 KHz http://www.cco.caltech.edu/~boyk/spectra/spectra.htm Quote Link to comment Share on other sites More sharing options...
psg Posted July 21, 2006 Share Posted July 21, 2006 Slight contradiction of this: Author's Notes, May 4, 2000 At the request of people involved in standards-setting for audio, who wanted this information made available as soon as possible, I published this original paper here, rather than in a professional journal. with this at the end: This paper is being published long after the work was completed because of the difficulty of creating publication-quality graphs from the data. I spent a lot of time and money discovering half a dozen programs that would not make acceptable graphs. Finally, Caltech undergrad Peter Oakley learned to use Matlab to do the job, and carried out the work reliably and creatively. He may have a Caltech email address, but he's not a scientist. I don't know how credible any of this is. I have no idea if the spectral content at 50 KHz is real or simply leakage from the peak a bit past 20 KHz. I wonder if this would get past peer-review. Peter, Ph.D. Quote Link to comment Share on other sites More sharing options...
Rivendell61 Posted July 21, 2006 Share Posted July 21, 2006 Peter, The Boyk paper (next comes Oohashi) has been bouncing around audio web sites for a long time, and I don't think the general premiss is much disputed--or new. What it does not address is the desirability of reproducing that high frequency information. That question seems to be always answered in the negative (if we want to get an accurate representation of the event in the audible range). And there is vinyl.... Until the mid-60's or so it was limited to about a 12kHz top. And modern Lps usually top out at c.15+kHz. There are claims of higher than 20kHz frequencies being possible--but this is not the norm, even on 'audiophile' releases. Yet no one seems to complain about a lack of top end. So....not sure why this high frequency thing gets advocated by vinyl folks. Lots of effort (by Sony, Philips, etc) went into finding some excuse for ultrasonic reproduction due to SACD, DVD-A, etc. But there has been zero evidence (in theory or listening tests) discovered to date. In fact there are significant arguments against running ultrasonics through amplifiers and speakers (Kaoru and I believe Griesinger have written on this). Mark Quote Link to comment Share on other sites More sharing options...
psg Posted July 21, 2006 Share Posted July 21, 2006 Thanks Mark. Peter, The Boyk paper (next comes Oohashi) has been bouncing around audio web sites for a long time, and I don't think the general premiss is much disputed--or new. Still would have been nice to see peer-review on it. He wasn't really in a hurry since he took years to write it up. It doesn't help the credibility factor. Quote Link to comment Share on other sites More sharing options...
jorjen Posted July 21, 2006 Share Posted July 21, 2006 There's Life Above 20 Kilohertz! A Survey of Musical Instrument Spectra to 102.4 KHz http://www.cco.caltech.edu/~boyk/spectra/spectra.htm Not with my ears. [] Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted July 21, 2006 Share Posted July 21, 2006 I think my dog would appreciate the extended response more than me. I'd like to see the harmonic extension for an ambulance siren. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted July 22, 2006 Share Posted July 22, 2006 , Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted July 22, 2006 Share Posted July 22, 2006 well... there might be some 50 KHZ info , or, is it noise ... but I guarantee your amp is limited to not reproducing it, so as RF doesn't drive the amp into oscillation ... Quote Link to comment Share on other sites More sharing options...
DRBILL Posted July 22, 2006 Share Posted July 22, 2006 I am not inclined to dismiss this offhand. Although we might not "hear" the >20kh sounds, we may react to them emotionally. Tube TVs used to emit a supersonic whistle from the HV supply. It would make me edgy to be around them in close proximity. As in all academic endeavors, "more research is needed." DRBILL Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.