Playing discord on the bottom register of a pope organ produces some very obvious low frequency beat notes. But whether you hear them or feel them .... :-) On 19 May 2014 23:37, Brooke Clarke wrote: > Hi Rupert: > > If you look at the plot at: > http://people.xiph.org/~xiphmont/demo/neil-young.html > showing threshold of hearing and threshold of pain, at the upper frequenc= y > end the two curves intersect, but at the low > frequency end the plot has been artificially truncated. It's clear the > people can hear sounds lower the 20 Hz, it's > just not plotted. Yes it takes more power to hear, but when that amount o= f > power is present you do hear (and not > experience any pain). > http://www.prc68.com/I/HomeTheater.shtml#SSS > > When I watch movies on a 7.1 surround sound system (the ".1" is the sub > woofer) you really do experience those low > frequencies. > > Note elephants and other animals can generate and hear infrasound that we > can not hear. > http://www.prc68.com/I/Sensors.shtml#Isnd > > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > > piclist-request@mit.edu wrote: > > [OT] Audio frequencies > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 __________________________________________ David C Brown 43 Bings Road Whaley Bridge High Peak Phone: 01663 733236 Derbyshire eMail: dcb.home@gmail.com SK23 7ND web: www.bings-knowle.co.uk/dcb --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .