<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Short Treble (sustain?)</title></head><body> <div>Del, Ron N. and all,</div> <div><br></div> <div>The string buzzing on the side of the agraffe slot is most certainly the problem. Earlier in my career I recapped the failed bridges on a Grotrian 220. Since the owner was travelling to Germany on business, when he visited the factory they sold him a replacement treble bridge cap. Unfortunately, the new bridge cap was afflicted with the same 'disease' which was common to '70s era Grotrians<font color="#0000FF"> (I have no idea if it remains a problem with their contemporary instruments)</font>. However, the bridge pin spacing was so close that there was virtually no free space between the string and the adjacent bridge pin. Consequently, there remain several notes on my client's Grotrian 220 which have string noise at the bridge pins<font color="#0000FF"> (which varies in intensity according to the relative humidity at the time)</font>. A gentle side pressure on an offending bridge pin will stop the noise.</div> <div><br></div> <div>These Grotrian bridges from the '70s are prone to failure on account of the close bridge pin spacing. There is simply insufficient bridge wood around the pins to provide adequate support for the side thrust on the pins. On Grotrians from earlier periods they have used a wider bridge pin spacing and they do not have the same problem. Isn't it amazing how corporate knowledge often fails to be passed down from one generation to another? The 'Johnny come latelys' turn up with new thinking but fail give appropriate consideration to lessons learned long ago by an older generation of thinkers. I'm all for innovative technologies, but one should come to it after stepping off from the knowledge which has gone before.</div> <div><br></div> <div>Clearly, the idea of placing a damping material on a noisy string segment<font color="#0000FF"> (wether it be new-age silicon as in the case of the Stuart agraffe, a piece of felt or a lump of fat from under the barbecue)</font>, its still is just a case of fixing the symptom instead of addressing the cause of the disease.</div> <div><br></div> <div>The bridge agraffe we have been discussing is a case in point. It simply wasn't thought through prior to execution. I concur with your views Ron N. and Del, with regard to widening the slots and using rolled pins as a solution. Less overall height would be a plus as well. As you and I have both mentioned previously Ron N., it would allow for the retention of a more sensible bridge height and stiffness.</div> <div><br></div> <div>Ron O.</div> <div><br></div> <blockquote type="cite" cite>----- Original Message -----<br> From: "Ron Nossaman" <RNossaman@cox.net><br> To: "Pianotech" <pianotech@ptg.org><br> Sent: November 01, 2003 8:23 PM</blockquote> <blockquote type="cite" cite>Subject: Re: Short Treble (sustain?)</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite>I suspect the problem is with the string buzzing against the side of the</blockquote> <blockquote type="cite" cite>slot.</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite>Del</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite> Perhaps, though I have a hard time imagining much vibration excursion in</blockquote> <blockquote type="cite" cite> that short segment. At that, how difficult or more expensive is a wider</blockquote> <blockquote type="cite" cite> slot, as long as you're cutting one anyway? It's not like it will cost</blockquote> <blockquote type="cite" cite> anything important in rigidity. A grooved center rod would help too,</blockquote> <blockquote type="cite" cite>though</blockquote> <blockquote type="cite" cite> it would cost a bit more to produce.</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite> Ron N</blockquote> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite>-------------<br> <br> As do I. I did think it a possibility, though, as I worked with similar<br> devices at Baldwin. The easiest way to solve the problem (if it exists)<br> (and, other than putting some damping material between the leading<br> termination and the center deflector rod) is, as you suggest, to groove the<br> center rod. This could be rolled and, in quantity, is not as expensive as<br> you might think. In limited quantities, however, it might well be a factor.<br> This can be used to solve another problem as well -- the varying string<br> deflection angles as the wire size changes. I played around with several<br> groove depths, deeper in the low tenor and bass, more shallow in the<br> tenor/treble.<br> </blockquote> <blockquote type="cite" cite>Del</blockquote> <div><br></div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:info@overspianos.com.au<br> _______________________</font></div> </body> </html>