This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Structurally, it seems to me that the bridge would be least likely to roll at the greatest point of curvature. Consider a piece of steel, 1" wide, 1/8" thick, 2 feet long, welded to a thin piece of sheet metal on edge. This is our bridge on the soundboard, easy to rotate forward and backward. It has no support behind or before it. Now imagine the bar stock bent into an L shape welded on edge on the sheet metal. Near the bend, the corner of the L, the bar stock will be very strong and resistant to rolling. It has the leg behind it to support the direction of the loading. But as force is applied closer to the ends of the legs it will loose strength and rotate easier in that local area. Dean May -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Terry Sent: Friday, February 11, 2005 5:23 PM To: pianotech@ptg.org Subject: Killer Octave & Pitch Raise When I raise the pitch of a piano, typically I find that I need to pull an area of the treble, commonly around the sixth octave or so, a bit extra so that area does not end up flat when the pitch raise is completed. I use typical pitch raise overpulls - 20% in bass, 25% in tenor and 33% or so in treble - but that one octave or so in the treble needs to go a little further - maybe 35 or 38%. I find this to be true on most pianos. My understanding is that one factor that may conspire to produce a killer octave (low volume and/or short sustain) in a piano is the fact that the killer octave area is also the area the long bridge is curved most - rather than having the downbearing supported in part by a straight (or nearly so) bridge (like in the tenor), the curved part of the long bridge in the killer octave area is more prone to rolling - I know, not rolling - actually soundboard deformation - but I'm trying to point out that it can rotate in this area more easily than other areas. My question is - might these two phenomena be related? Is the killer octave area more prone to going flat because the bridge is rotating (I suppose in part due to soundboard not having enough support in that area)? Thanks for any thoughts. Terry Farrell ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/d7/3b/02/95/attachment.htm ---------------------- multipart/alternative attachment--
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