<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2900.2802" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT size=1><FONT face=Arial><EM>....................."I seem to remember reading somewhere that it was around 30 hz.  Very iffy.<BR><BR>    /Is the point which beat rate is too fast to  <BR>    be unusable for us aural tuners any higher than 12 bps? Maybe that's  <BR>    another measurement for an ETD./<BR><BR></EM><U><FONT color=#ff0000 size=3><STRONG>Definitely </STRONG></FONT></U></FONT><FONT face=Arial><EM> (Ric) not.  You can use 15 - 20 bps no problem.  That is to say if <BR>you are comparing two intervals in which the reference note</EM> </FONT><FONT face=Arial><U><FONT color=#ff0000 size=2><STRONG>yields <BR></STRONG></FONT></U><EM>roughly 20 bps for both intervals... an aural comparison is easy enough <BR>to accomplish.".............</EM></FONT></FONT></DIV> <DIV><STRONG><FONT face=Arial size=2></FONT></STRONG> </DIV> <DIV><STRONG><FONT face=Arial size=2>This is the reason why AO (or A1) is the first note or lowest note on the piano. Any frequency (read as beat rate) lower than 27.5 Hz is no longer perceived as a sound by the "human" brain. In theory we start to hear the separate beats or pulses.</FONT></STRONG></DIV> <DIV><STRONG><FONT face=Arial size=2></FONT></STRONG> </DIV> <DIV><STRONG><FONT face=Arial size=2>AF</DIV> <DIV><BR></DIV></FONT></STRONG></BODY></HTML>