Mythbusters and "The Disco Dump"
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From: Arny Krueger on 3 Nov 2006 08:46 "Mark & Mary Ann Weiss" <mweissX294(a)earthlink.net> wrote in message news:cLD2h.144090$bL1.9608(a)fe04.news.easynews.com > "George Gleason" <tbmoas58(a)peoplepc.com> wrote in message > news:fDXUg.6949$o71.3730(a)newsread3.news.pas.earthlink.net... >> Well even 154 dB at 20 cycles could not induce anything >> close to "the brown note" >> it looked like fun but as for soiling ones shorts from >> low freq sound,at least with a healthy person >> just isn't going to happen I've personally experienced this effect to the point of discomfort but not embarassment. The discomfort would have probably resulted in embarassment if it continued for much longer. It takes more like 130 dB @6 Hz to induce the necessary gut resonances. The originator of externally-induced bowel discharge was probably Tesla. His story involved a shaker table large enough to stand on. > I highly doubt the 20 Hz component of that test was above > 124dB with that gear. Conventional drivers like that have > more distortion than fundamental output when driven below > Fc. > For some real output below 20Hz, check this out: > http://www.youtube.com/watch?v=O2rJSZKZsyQ What you can't see is the means used to move the carpeting. The video is not what it seems.
From: Mark & Mary Ann Weiss on 3 Nov 2006 21:38 > > I highly doubt the 20 Hz component of that test was above 124dB with that > > gear. Conventional drivers like that have more distortion than fundamental > > output when driven below Fc. > > > > For some real output below 20Hz, check this out: > > > > http://www.youtube.com/watch?v=O2rJSZKZsyQ > > > the test was done to simulate something a club goer would encounter > they had 150 some dB at 20 and like 120 something at 8 or 9 cycles > I don't remember the exact details as that was mot\re than a month ago and I > didn't take notes in case this came up again > I am sure it will be repeated as TV often does,you can see it then > George > > Mythbusters is hardly scientific, especially in the area of technical matters like this. The 150dB was probably all distortion harmonics from 40-2000Hz. Conventional drivers used in PA equipment like that shown in that episode are not designed to produce anything useful below 45Hz and even at that frequency are about 10dB down from their rated SPL frequency. I'll believe it when I see an earthquake triggered by the experiment. But until then...
From: Mark & Mary Ann Weiss on 3 Nov 2006 21:41 going to happen > > I've personally experienced this effect to the point of discomfort but not > embarassment. The discomfort would have probably resulted in embarassment if > it continued for much longer. > > It takes more like 130 dB @6 Hz to induce the necessary gut resonances. So have I. :-) > The originator of externally-induced bowel discharge was probably Tesla. His > story involved a shaker table large enough to stand on. > > > I highly doubt the 20 Hz component of that test was above > > 124dB with that gear. Conventional drivers like that have > > more distortion than fundamental output when driven below > > Fc. > > > For some real output below 20Hz, check this out: > > > http://www.youtube.com/watch?v=O2rJSZKZsyQ > > What you can't see is the means used to move the carpeting. The video is > not what it seems. Since I'm the author of that video, I DO know the means used to lift the carpet: Infrasound. The SPL I measured in the 16Hz passband at 30' was 133dB. I chose 30' because the SPL was beyond my equipment measurement capability at the more customary 1 meter. Each subsonic transducer is capable of displacing 1250 cu in of air. Compare that to 177 cu in for the average 18" woofer and you start to get the picture...
From: Earl Grey on 3 Nov 2006 22:29 Mark & Mary Ann Weiss wrote: >>> I highly doubt the 20 Hz component of that test was above 124dB with > that >>> gear. Conventional drivers like that have more distortion than > fundamental >>> output when driven below Fc. >>> >>> For some real output below 20Hz, check this out: >>> >>> http://www.youtube.com/watch?v=O2rJSZKZsyQ >>> >> the test was done to simulate something a club goer would encounter >> they had 150 some dB at 20 and like 120 something at 8 or 9 cycles >> I don't remember the exact details as that was mot\re than a month ago and > I >> didn't take notes in case this came up again >> I am sure it will be repeated as TV often does,you can see it then >> George >> >> > > Mythbusters is hardly scientific, especially in the area of technical > matters like this. The 150dB was probably all distortion harmonics from > 40-2000Hz. Conventional drivers used in PA equipment like that shown in that > episode are not designed to produce anything useful below 45Hz and even at > that frequency are about 10dB down from their rated SPL frequency. I'll > believe it when I see an earthquake triggered by the experiment. But until > then... > > > You should view the episode before you rush your judgement The measurement was done by John Meyer and a fellow engineer from Meyer Sound Labs. Those guys have far more credibility in the sound industry than you and your home project
From: Earl Grey on 3 Nov 2006 22:38
Earl Grey wrote: > Mark & Mary Ann Weiss wrote: >>>> I highly doubt the 20 Hz component of that test was above 124dB with >> that >>>> gear. Conventional drivers like that have more distortion than >> fundamental >>>> output when driven below Fc. >>>> >>>> For some real output below 20Hz, check this out: >>>> >>>> http://www.youtube.com/watch?v=O2rJSZKZsyQ >>>> >>> the test was done to simulate something a club goer would encounter >>> they had 150 some dB at 20 and like 120 something at 8 or 9 cycles >>> I don't remember the exact details as that was mot\re than a month >>> ago and >> I >>> didn't take notes in case this came up again >>> I am sure it will be repeated as TV often does,you can see it then >>> George >>> >>> >> >> Mythbusters is hardly scientific, especially in the area of technical >> matters like this. The 150dB was probably all distortion harmonics from >> 40-2000Hz. Conventional drivers used in PA equipment like that shown >> in that >> episode are not designed to produce anything useful below 45Hz and >> even at >> that frequency are about 10dB down from their rated SPL frequency. I'll >> believe it when I see an earthquake triggered by the experiment. But >> until >> then... >> >> >> > You should view the episode before you rush your judgement > The measurement was done by John Meyer and a fellow engineer from Meyer > Sound Labs. > Those guys have far more credibility in the sound industry than you and > your home project http://www.meyersound.com.au/brownnote.shtm |