<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Tuning problems: capo improvement suggestions</title></head><body> <div>At 10:34 AM -0600 25/1/03, Ron Nossaman wrote:</div> <div><br> <br> </div> <blockquote type="cite" cite>I think that half agraffes instead of a V bar are a good idea.</blockquote> <div><br></div> <div>Indeed, as Blüthner have used for many years.</div> <div><br></div> <blockquote type="cite" cite>Now I have a question. If string cutting of iron V bars is such a horrible problem, why isn't it such a horrible problem in agraffes?</blockquote> <div><br></div> <div>I think it is Ron, but the symptom<font color="#0000FF"> (string noise)</font> as it appears in the capo-with-front-duplex sections doesn't present to the same degree in the agraffed section, since the<font color="#0000FF"> (usually)</font> shorter free string length between the agraffe and the bearing felt or bearing bar reduces the ability for string noise to develop. Mind you, many agraffes do present with a slight 'zing' which is directly attributable to poorly shaped or deformed string holes.</div> <div><br></div> <div>Notice that upright pianos are far less subject to string noise, yet the V bars in many cases are quite poorly shaped. Furthermore, the pressure bar is often of a quite large radius also. Nevertheless the shorter free length between the V bar and pressure bar tends to control string noise.</div> <div><br></div> <div>In 1995 I rebuilt a Grotrian 275 to original spec. The exceedingly long free string length between the agraffes and the bearing bar allowed the piano to produce unacceptable string noise. As a post-rebuild fix for this piano I manufactured and fitted an overhead pressure bar similar to what one would find on an upright piano. After some experimentation with position I found the 'most open' tone to occur when the bar was placed about 20 mm from the agraffe line. The tonal improvement of this piano with the pressure bar was nothing short of dramatic.</div> <div><br></div> <div>Those of you who saw our no. 003 piano at Reno, will now understand why we manufactured and fitted an overhead pressure bar behind the agraffe line. For those of who didn't see it, an overhead image which shows the pressure bar can be seen at;</div> <div>http://overspianos.com.au/OS003.html</div> <div><br></div> <div>I don't regard the bar itself to be a critical factor, but when someone else designed the plate you are using<font color="#0000FF"> (and that someone designed the plate such that the bearing felt was too far away from the agraffe)</font>, it becomes necessary to add a bar to achieve the shorter string free length.</div> <div><br></div> <div>Ron O</div> <div><br> _______________________________________________</div> <blockquote type="cite" cite>pianotech list info: https://www.moypiano.com/resources/#archives</blockquote> <div><br></div> <div><br></div> <x-sigsep><pre>-- </pre></x-sigsep> <div>_______________________<br> <br> OVERS PIANOS - SYDNEY<br> Grand Piano Manufacturers</div> <div><br></div> <div>Web: http://overspianos.com.au</div> <div>mailto:info@overspianos.com.au</div> <div>_______________________</div> </body> </html>