<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2600.0" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT color=#0000ff>Comments below:</FONT></DIV> <DIV><FONT color=#0000ff></FONT> </DIV> <DIV><FONT color=#0000ff>Some of my input below is playing the devil's = advocate - I'm trying to push this so that I might understand some of this stuff.</FONT></DIV> <DIV><FONT color=#0000ff></FONT> </DIV> <DIV><FONT color=#0000ff>Terry Farrell</FONT></DIV> <DIV> <SPAN id=__#Ath#SignaturePos__></SPAN> </DIV> <DIV>----- Original Message ----- <DIV>From: <<A = href="mailto:A440A@aol.com">A440A@aol.com</A>></DIV> <DIV>To: <<A = href="mailto:pianotech@ptg.org">pianotech@ptg.org</A>></DIV> <DIV>Sent: Friday, October 25, 2002 11:33 AM</DIV> <DIV>Subject: Re: Soundboard Panel Grain Angle</DIV></DIV> <DIV><BR></DIV> <DIV>> Greetings, <BR>>    There are acoustic reasons = for quarter sawn wood being used.  Sound <BR>> transmission is much = better with the grain than across it, (something on the <BR>> order of 3 = times faster,too?)  I believe this is because there is a loss of <BR>> = acoustical energy every time there is a change from one medium to the = next, <BR>> and going across the grain requires the energy to go from one = density of wood <BR>> to another with every "ring line", effectively losing = energy at every step. </DIV> <DIV> </DIV> <DIV><FONT color=#0000ff>Then it would seem that quarter sawn spruce = would effectively stop/minimize sound transmission across the grain. If the = boards were flat sawn, the sound would not have to cross between hard and soft = layers. Going along the grain, it would seem as though there might not be much difference between flat and quarter sawn - just that quarter sawn would = be lots of little hard grain strips and flat would be larger more continuous = layers of hard wood for sound to "travel along".</FONT></DIV> <DIV> <BR>> Harder material transmits the sound faster, too, so = the harder grain <BR>> transmits the sound better and faster than the = softer "summer" wood. </DIV> <DIV> </DIV> <DIV><FONT color=#0000ff>I'll buy that. That applies to the previous statement.</FONT></DIV> <DIV> <BR>>     The more truly quarter sawn it = is, the more contact there will be between <BR>> the harder grain and the bridge.</DIV> <DIV> </DIV> <DIV><FONT color=#0000ff>Yes, I see that. What about if you had flat = sawn and simply planed it until you had a nice dense late-season growth ring = near the surface? Then you would have 100% contact with the harder grain and = the bridge. </FONT></DIV> <DIV> </DIV> <DIV>>  There is a reason that the best sounding <BR>> boards = have the bridges directly connected to the ribs, since the ribs <BR>> = transmit the energy to the entire board with greater efficiency than if all <BR>> = the energy had to spread across the grain from the bridge. </DIV> <DIV> </DIV> <DIV><FONT color=#0000ff>I suppose then this would get into advantages/disadvantages to having the ribs quarter sawn or flat sawn or = somewhere in between. Should they be one way or another because of = acoustical properties, or would/should that decision be based on strength/stiffness = properties of the various cuts?</FONT></DIV> <DIV> </DIV> <DIV>SNIP</DIV></BODY></HTML>