<!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 6.00.2800.1400" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2> <DIV><FONT face=Arial size=2>MiniMens piano string simulator introduces the new "contact ratio" parameter for = analyzing the break in the scale from blank strings to wrapped = strings.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV>On the lower strings, it is possible that the hammer has multiple = contacts with the string. (see contact force graph)</DIV> <DIV><IMG alt="" hspace=0 = src="cid:000f01c41e58$83b37cb0$2dcefea9@BERNHARDNEU" align=baseline border=0></DIV> <DIV>contact force history for key F-21, string length 1475 mm (58 inch) = diameter Nr. 20 (Steinway model B) hammer speed 3 m/s. The single peak = at 11 ms indicates the recontact of the string with the hammer, when the wave = arrives the hammer after the bridge reflection.</DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>Contact ratio means contact time of all = contacts of the hammer with the string, divided by the time, the wave needs to = run from the hammer to the bridge and back to the hammer. If the time is equal, = the ratio becomes 1.0, what means that the hammer is in a synchronous = movement with the string. A lower contact ratio will produce a more partial = pronounced tone, whereas a higher contact ratio increases the losses of the higher partials.</FONT></DIV> <DIV> </DIV> <DIV>It has been found, that on good instruments (like the Steinway = Model B or D) the wires are always choosen in that way that this contact ratio has nearly the same value (but only true when considering all contacts). Changing only 1 diameter of the copper = wire more or less, will already produce different contact ratios. Since it was not = possible to do dynamic simulations at the time when this scales where = designed, one must assume that the best fit was found by try. It is amazing = to find with dynamic simulation the proove that the = scale designers had found the best wire combination. </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV>(first numeric field is contact time, second field ist wave = time)</DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2> </FONT><IMG alt="" hspace=0 src="cid:001001c41e58$83b5c6a0$2dcefea9@BERNHARDNEU" align=baseline border=0></DIV> <DIV>original contact ratio (0,64) for F21: <DIV>string length 1475 mm (58 inch) diameter 1,125 mm (0,0443 = inch)</DIV></DIV> <DIV> </DIV> <DIV> </DIV> <DIV><IMG alt="" hspace=0 = src="cid:001101c41e58$83b5c6a0$2dcefea9@BERNHARDNEU" align=baseline border=0></DIV> <DIV> <DIV>original contact ratio (0,64) for E20: (contact times and wave = times are different)</DIV> <DIV>string length 1025 mm (40,35 inch) core wire 0,95mm = (0,0374 inch) wound wire <STRONG>0,55 mm</STRONG> <STRONG>(0,0217 inch)</STRONG> </DIV></DIV> <DIV> </DIV> <DIV> </DIV> <DIV><IMG alt="" hspace=0 = src="cid:001201c41e58$83b5c6a0$2dcefea9@BERNHARDNEU" align=baseline border=0></DIV> <DIV> <DIV> <DIV>modified contact ratio for E-20 (red marker for E-20, blue marker = for F-21):</DIV> <DIV> <DIV>string length 1025 mm (40,35 inch) core wire 0,95mm = (0,0374 inch) wound wire <STRONG>0,6 mm</STRONG> <STRONG>(0,0236 inch)</STRONG> </DIV></DIV></DIV> <DIV> </DIV> <DIV> </DIV> <DIV><IMG alt="" hspace=0 = src="cid:001301c41e58$83b5c6a0$2dcefea9@BERNHARDNEU" align=baseline border=0></DIV> <DIV> <DIV>modified contact ratio for E-20 (red marker for E-20, blue marker = for F-21):</DIV> <DIV> <DIV>string length 1025 mm (40,35 inch) core wire 0,95mm = (0,0374 inch) wound wire <STRONG>0,5 mm (0,0197 inch) </STRONG></DIV> <DIV><STRONG></STRONG> </DIV> <DIV>The contact ratio parameter together with inharmonicity = are very important paramters that will limit the number of wire combinations at = the scale break and helps greatly to reduce sound differences at this most = delicate part of the scale.</DIV> <DIV> </DIV> <DIV>Best regards</DIV> <DIV> </DIV> <DIV>Bernhard Stopper</DIV> <DIV>Klavierbaumeister</DIV> <DIV> </DIV> <DIV>Info about the MiniMens/Mensurix Software at:</DIV> <DIV><A href="http://www.piano-stopper.de/html/homepe.htm">http://www.piano-sto= pper.de/html/homepe.htm</A></DIV> <DIV> </DIV></DIV></DIV></DIV></FONT></DIV></BODY></HTML>