This is a multi-part message in MIME format. ---------------------- multipart/related attachment ------=_NextPart_001_0046_01C41E70.3886B820 Hello Bernhard, 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... Personnally, as an engineer, I already made the hypothesis of multiple = contacts with the strings in that range, creating this parasitic noise = (see below)... I would be very much interested to have your feedback on this point. Cheers, Stephane Hanriat - Owner of Shigeru Kawai SK3 ______________________________________________ Hello List, I'm back with another topic I would like to share with you. 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 -:) 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... 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. 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). 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). Cheers, Stephane Hanriat, the french guy who loves the Shigeru's. ----- Original Message -----=20 From: Bernhard Stopper=20 To: Pianotech=20 Sent: Friday, April 09, 2004 7:31 PM Subject: Analysis of plain wire string/wound wire break on a Steinway = Model Bwith MiniMens 1.0.6 MiniMens piano string simulator introduces the new "contact ratio" = parameter for analyzing the break in the scale from blank strings to = wrapped strings. On the lower strings, it is possible that the hammer has multiple = contacts with the string. (see contact force graph) 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. 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. 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.=20 (first numeric field is contact time, second field ist wave time) =20 original contact ratio (0,64) for F21:=20 string length 1475 mm (58 inch) diameter 1,125 mm (0,0443 inch) original contact ratio (0,64) for E20: (contact times and wave times = are different) string length 1025 mm (40,35 inch) core wire 0,95mm (0,0374 inch) = wound wire 0,55 mm (0,0217 inch)=20 modified contact ratio for E-20 (red marker for E-20, blue marker for = F-21): string length 1025 mm (40,35 inch) core wire 0,95mm (0,0374 inch) = wound wire 0,6 mm (0,0236 inch)=20 modified contact ratio for E-20 (red marker for E-20, blue marker for = F-21): string length 1025 mm (40,35 inch) core wire 0,95mm (0,0374 inch) = wound wire 0,5 mm (0,0197 inch)=20 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. Best regards Bernhard Stopper Klavierbaumeister Info about the MiniMens/Mensurix Software at: http://www.piano-stopper.de/html/homepe.htm ------=_NextPart_001_0046_01C41E70.3886B820 An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/6d/8a/50/81/attachment.htm ------=_NextPart_001_0046_01C41E70.3886B820-- ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 36575 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/a7/9e/33/6d/attachment.jpe ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 17220 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/be/58/f4/8a/attachment.jpe ---------------------- multipart/related attachment A non-text attachment was scrubbed... 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