<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Hi Ric.. a couple comments below... <blockquote> Maybe one the strings had a false beat in it?  </blockquote> He does mention false beat briefly later on in the paragraph about figs 5 and 6.. so I think he probably would have been obs on this point. <blockquote> He doesn't write about talking to a piano technician in setting up his seeming elaborate laboratory like observation of piano stings in vibration.  Yet some of his "readings" might be due to a common phenomena known by technicians, but  not necessarily by Science Phds.   It seems in these "studies" the piano tuner is rarely mentioned, or if so, very offhandedly.  What other authority is there in scientific experiments on pianos?  </blockquote> This is actually a very good point. Few times are knowledgeable pianotechs involved in such efforts.  Dr. Coleman is a noted exception.... and there have been others.  The point was very much illustrated to me personally last year in Rochester when I had a chance to look at Stephen Birkets' computer action model. There was an obvious error (to a pianotech) in the movement of the jack at escapement... which he was able to adjust immediately by changing a few parameters.  Cool model tho... and no doubt when finished would be a very valuable tool for anyone wanting to do / learn about action designing <blockquote> OK, even if we all don't agree he knows exactly what is going on, the next step is replication.  Can anyone demonstrate "coupled motion"   Aurally, with tuning machines, only in a lab?    Rm </blockquote> I think you could start by very carefully doing the exact same experiment on say.. middle C.  Allow just two strings to vibrate...  insert a felt wedge about 10 seconds into things.... and watch the display.  Tunelab would be probably quite good at showing the results.  I might try it today for fun ! Cheers RicB </body> </html>