<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Hi Bob I dont try at this point to explain this or related questions.  I approach this from a slightly different angle.  If a change in string tension is at the root of the seasonal pitch changes we see, then it seems to me that one should first take a look at what needs to happen to the string itself for that to happen. One can use the formula provided by Galembo in sort of reverse fashion to do exactly this.  We observe a pitch change and <<attribute>> it to a a combination of a change in string tension and length....  so what such combination needs to occur to account for a given pitch change ? Doing this... one sees the required changes lack at present a good explanation... at least as far as I can see. If tension / lengths are changing to the degree required to account for the patterns and amounts of pitch changes we see... then the present explanations dont do it. Cheers RicB <blockquote> I've been following this discussion with some interest, and don't have any strong opinions or data on one side or the other of the soundboard/bridge debate.  However, I'd be interested in how the various factions explain the difference in humidity-related pitch change between the treble and bass bridges.  We've all observed the same sort of difference with both solid-body and cantilevered bridges, so I don't think it can be explained by simply saying, "Bass bridges have more wood, so they expand and contract more."  And how about those Yamaha C3s where the lowest octave of the tenor bridge has far greater seasonal pitch swings than any other part of the scale, treble or bass?   Just wondering Bob Hohf</blockquote> </body> </html>