This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment So what about the high treble? Often the top octave or more is quite = lively, loud and brilliant. Terry Farrell ----- Original Message -----=20 From: Marcel Carey=20 To: Pianotech=20 Sent: Sunday, October 05, 2003 5:49 PM Subject: RE: RC vs CC again Terry Farrell said: " When flat ribs are glued to a very dry flat panel, no force = vectors exist in the system. As the panel takes on moisture and the ribs = bend, the ribs will always be trying to pull the panel flat. Period. If = that assembly has crown, the ribs will always try to go straight by = pulling down on the panel. The compression forces in the panel are the = only thing that has provided the force necessary to bend the rib into a = crown. Whether or not you ever load that soundboard on top, the ribs = will always be fighting the panel compression to go flat. When you do = apply a load to the top of the soundboard, the compression on the panel = will increase, but the ribs will do nothing other than still try to go = flat. As the crown lessens under increasing load, the ribs will pull = downward a bit less, but only because they are being bent upwards less = by the panel. "=20 The way I see it, the reason why we have the killer octave problem = with mostly CC boards, is that the crown produced with the panel's = growth will be kind of proportional to the lenght of the ribs. So, with = this method the treble that always have shorter ribs than the tenor will = have less crown in the beginning. Since compression will affect the = board's with aging, we end up with a dead killer octave and a no crown = zone exactly where the ribs get shorter...in the killer octave. So I guess there is no way to have a decent board assembly that will = have a predictable lifespan with the Compression Crowned method. It's = physics. Again, I might be wrong, but I think I've seen the light. Marcel Carey, RPT Sherbrooke, QC ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/51/d9/56/3b/attachment.htm ---------------------- multipart/alternative attachment--
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