<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Damper Thump Noise</title></head><body> <div>Terry,</div> <div><br></div> <blockquote type="cite" cite><font face="Arial" size="-1">1950-ish Baldwin L grand, all original. Raise dampers with pedal and then release pedal. Dampers make quite an audible thump. Remove action and manually lift a dozen or so dampers and you get a similar thump - it is especially prominent with the bicords - very little noise from the flat dampers.</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Is this nothing more than the sound that 55 year-old grand dampers make? That is my strong suspicion.</font></blockquote> <div><br></div> <div>Certainly old and hardened dampers will increase the propensity for any damper system to thump on sudden return. However, another factor about which some piano manufacturers seem oblivious is the damper/pedal lift ratio.</div> <div><br></div> <div>We rebuilt a Baldwin SD-10 around 1989 and a Grotrian 275 concert piano in 1995. Complaints were received about the sustain pedal mechanism of both pianos. The Baldwin system had the thump which Terry described, while some pianists complained of a lack of control with the Grotrian. I looked at both pianos to find the difference between their damper lift systems, since we had rebuilt both pianos similarly, yet they had quite different characteristics.</div> <div><br></div> <div>The difference turned out to be the damper/sustain-pedal lift ratio. The Grotrian had 5 mm of pedal travel for every 1 mm of damper lift, while the Baldwin had around 2 mm of pedal travel for each mm of damper lift. After discovering the lift ratio to be a factor worthy of consideration, I examined a few other pianos from different manufacturers, concluding that the ratio should be no lower than 3.5:1 and no higher than 2.5. Our 225 piano has a ratio of 3.2.</div> <div><br></div> <div>I altered the trap-work levers on both pianos so that the damper/sustain lever ratio was adjusted to 2.5:1. I haven't had a damper complaint from either piano since. The Grotrian 275 is the broadcast and recording piano at Sydney FM radio station 2MBS FM. The Baldwin was used by us as a hire piano for many years. We sold it two years ago to a piano enthusiast here in Sydney. It is coming back to the workshop very soon for a minor overhaul which will include a re-string, and finally a proper fix for the action, which has always been heavy. Rick Wheeler has just completed a making a new keyboard and key-frame which I designed for fitting an Overs action to the Baldwin. I'm really looking forward to doing this refit, since I regard the Baldwin SD-10 as one of the very best contemporary concert grand piano designs (action and keyboard excepted). The major problem which held these pianos back from trumping their opposition (aside from poor action geometry) was sloppy workmanship and a complete lack of attention to detail. What a shame.</div> <div><br></div> <div>Ron O.</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:ron@overspianos.com.au<br> _______________________</font></div> </body> </html>