<!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 6.00.2737.800" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Hello Bernhard,</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Very interesting post. I'm wondering if = the "contact ratio" has something related to the "kissing noise" effect I've = observed on most of the Kawai piano I've played. Please see below the = post I sent to the list on the subject. I've working with Kawai Europe & = Japan to try understanding the root cause, but they were not able to explain this = parasitic noise to me, just saying that this is well known and likely = due to hammer condition ??? I've never been convinced about that explanation, = since only very few notes are impacted (few first notes below the break tri-cord/bi-cord) and only on the 1.78m and 1.86m piano...</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Personnally, as an engineer, I already = made the hypothesis of multiple contacts with the strings in that range, creating = this parasitic noise (see below)...</FONT></DIV> <DIV><FONT face=Arial size=2>I would be very much interested to have = your feedback on this point.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Cheers,</FONT></DIV> <DIV><FONT face=Arial size=2>Stephane Hanriat - Owner of Shigeru = Kawai SK3</FONT></DIV> <DIV><FONT face=Arial size=2>______________________________________________</FONT></DIV> <DIV> <DIV><FONT face=Arial size=2>Hello List,</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I'm back with another topic I would = like to share with you.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>During the process of selecting my = Shigeru piano, I played a lot of Kawai instruments, and I found a strange noise impacting = very few notes, but always the same notes : 23, 24 and 25. The noise looks = like a whistling appearing at the attack, and is very easy to ear when playing = a non legato trill at pianissimo. This noise is clearly audible on most of = RX-2, SK2 (1.78 m), RX-3 and SK3 (1.86 m). Very difficult to ear it on larger = instrument. RX-6 or SK6 (2.12 m) do not have it.  - sorry for the metric unit -:)</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I had extensive discussions on that = with our french MPA who is now an expert to determine whether an instrument is having = the noise or not. We have contacted Kawai in Japan. They replied that this is well = known as "kissing noise" and that mostly all prestigious brands are facing = this problem that originates from hammer conditions. Kawai also told us that Steinway has extensively studied the topic without identifying = the root cause ; and when the problem is creating inconvenience at playing, = Steinway is replacing the hammers...</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>We made some experiments at the french = Kawai show room on some RX, without being capable to find a reliable fix. Some = pianos were not having this kissing noise, but most of them had it in the showroom.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>When I play grand pianos in this size = range, I always discreetly check the stuff... but I've not seen this kissing = noise as present as on the Kawai. I can tell you I've been cautious when = selecting my Shigeru, so it took me 2 years to find an SK3 almost free from kissing = noise (but not completely free).</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>If some of you have an explanation = and/or a fix, I would be very excited to learn this (and lot of MPAs too, believe me).</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Cheers,</FONT></DIV> <DIV><FONT face=Arial size=2>Stephane Hanriat, the french guy who = loves the Shigeru's.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV></DIV> <BLOCKQUOTE dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B> <A title=b98tu@t-online.de = href="mailto:b98tu@t-online.de">Bernhard Stopper</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A = title=pianotech@ptg.org href="mailto:pianotech@ptg.org">Pianotech</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, April 09, 2004 = 7:31 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Analysis of plain wire = string/wound wire break on a Steinway Model Bwith MiniMens 1.0.6</DIV> <DIV><BR></DIV> <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:004001c41e5f$74dca480$c1c94152@bureau" 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:004101c41e5f$74deee70$c1c94152@bureau" 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:004201c41e5f$74deee70$c1c94152@bureau" 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:004301c41e5f$74deee70$c1c94152@bureau" 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:004401c41e5f$74deee70$c1c94152@bureau" 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></BLOCKQUOTE></BODY></HTM= L>