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From: Ross
Remote Name: 76.101.10.136
Date: 26 Feb 2007
Time: 07:50:19 -0500
Luthier’s Blog 2/26/07 Here’s Monday again. Retraining day. It’s usually good, though, to have the benefit of perspective which the weekend gives. I made the mistake of leaving the shop in relative disorder on Sat. and now need to reorganize before I can actually do any real (paying) work. Golly. I have been trying to find the documentation to support the unfinished thought I had 3 days ago about soundboard length as dictated by fundamental frequency. I believe the length of the fundamental freq.‘s sound wave must be supported by a soundboard of at least a quarter of that length. I can’t find the reference, though. It has made me review my copy of Musical Acoustics by Charles Culver of Carleton College, though. Also the excellent music acoustics site of the University of South Wales in Australia, Research in Guitar Acoustics. Also The Glenbrook Physics tutorial on frequency and harmonics, Fundamental Frequency and Harmonics. And a bunch more. Reviewing this stuff is good, because, although it’s sometimes tough reading, you always bring to the study more information and experience than you had the first time you read it. Sometimes a bell goes off. “Finally” I say to myself “I think I understand this.” That or “Duh….?”. If what I believe about plate length is true, it would require a sound board with a length of approx. 3 ˝ feet to support the fundamental of the lo “E” string. The first fully supported fundamental would not occur until around the “C” on the 5th string. All the fundamentals we “hear” are actually assorted harmonics working together to suggest the fundamental. A little thought will tell my luthier that to place our bridge in an effective position on a soundboard of the length necessary to support all the fundamental frequencies down to the lowest note on our 25.5” guitar will leave precious little neck standing free of the body on which to play. Not to worry, though. Generation upon generation of musicians have come to standardize the accepted sound that constitutes “The Guitar Sound”, and if a musician actually heard all the lower fundamentals that the strings can produce, he probably would think it sounds odd. No sale there. If the luthier varies the location of the lowest supported fundamental by more than a half tone, the difference will probably disqualify the instrument from serious consideration for use in the intended idiom. I will return to the subject of plate size when I can locate the appropriate reference. In the meantime, I think it’s time to compile my list of things that I don’t understand about instrument design. Tomorrow. 9:04 a.m.