This is a multi-part message in MIME format. ---------------------- multipart/related attachment ------=_NextPart_001_0008_01C425A4.3E027830 Dear Stephane, After i entered the string measures that you sent me, MiniMens reports = clearly that this a problematic string length/diameter setting. The = Longitudinal wave matches very close the 13. transversal partial, what = results in a strong resonance effect. (speaking length 1058 mm, 0,975, = plain wire, copper 0,5 mm) The three pointers in the "Longitudinal Freq." meter representing the = first 3 longitudinal partials in the transversal partial spectrum = (represented by the meters scale, transversal partials reported from = partial Nr. 12-48, the first longitudinal partial has a frequency of = 1290 Hz.=20 The meter indicates, that the longitudinal partial matches slightly = above the 13. transversal partial. Physically, longitudinal partials near to Odd transversal partials = produce a strong resonance with 2 times the frequency of the odd = transversal partial, what means in this example, the 1. longitudinal = partial has a resonance with the 26. transversal partial. Due to = inharmonicity of the 26. partial, this occurs if the frequency of the = longitdunal partial is slightly above the 13. transversal partial. In the sound simulation produced by the MiniMens Simulator one can = clearly here the whistling produced by the longitudinal resonance. listen to the sound by clicking the link: http://www.piano-stopper.de/dl/Kawai_G23_0,975_0,5.wav a solution would be to change the diameters to 1,0 mm for the core wire = and 0,475 mm for the copper diameter. (inharmonicity must be checked with the neighbour keys) what would sound like this: http://www.piano-stopper.de/dl/Kawai_G23_1,0_0,475.wav Regards, Bernhard Stopper info about the MiniMens Simulator: www.piano-stopper.de ----- Original Message -----=20 From: St=E9phane Hanriat=20 To: Bernhard Stopper ; Isaac Oleg=20 Sent: Sunday, April 18, 2004 9:15 PM Subject: Re: Analysis of plain wire string/wound wire break on = aSteinwayModel Bwith MiniMens 1.0.6 Hello Bernhard, Please find hereafter the measurements I made for the note G23 (the = note for which the kissing noise is the most audible): - speaking length : 1058 mm - steel diameter : between 0.9 & 1.0 mm (may be 0.95 mm) - section = looks square where covered with copper. - total wire diameter (includin copper wraping) : 1.9 mm (copper = should then be around 0.5 mm diameter) - strike point : 133 mm from the agraffe. Hope you'll be able to sdo something with those information. All the best, Stephane ----- Original Message -----=20 From: Bernhard Stopper=20 To: Pianotech=20 Sent: Friday, April 09, 2004 10:06 PM Subject: Re: Analysis of plain wire string/wound wire break on = aSteinwayModel Bwith MiniMens 1.0.6 Hello Stephane, is it possible for you to send me length and diameters for the keys = that causing the problems? I will do a dynamic simulation and a sound simulation with the = Minimens to find out what might be the case. Please let me know also = what kind of steel wire Kawai is using. MiniMens can do a sound = simulation that reports also the longitudinal waves. I rather think it = is a problem caused by the longitudinal waves (as Isaac Oleg metioned = also earlier), but to do an exact simulation, it is necessary to know = the value of youngs modulus of the core wire. (I actually only have it = for R=F6slau steel, it varies from 201 to 207 kN/mm=B2 depending on the = diameter). I "measured" youngs modulus of R=F6slau steel by simulating = different diameters with the Minimens Simulator and measured = inharmonicity on real instruments with same settings until the spectra = fit. I don=B4t think that the problems are caused by the multiple = contacts, because they are normal for the lower keys. on the lowest = octave the hammer does bouncing with the string up to 3 or 4 times, = thats normal. Best regards, Bernhard ----- Original Message -----=20 From: St=E9phane Hanriat=20 To: Pianotech=20 Sent: Friday, April 09, 2004 8:21 PM Subject: Re: Analysis of plain wire string/wound wire break on a = SteinwayModel Bwith MiniMens 1.0.6 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. ------=_NextPart_001_0008_01C425A4.3E027830 An HTML attachment was scrubbed... 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