freya
Oud Junkie
Posts: 276
Registered: 2-8-2004
Location: Asheville NC
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Mood: Happy in the mountains of WNC
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Diagonal Top Grain
FYI,
I was watching this guitar on eBay last week. It has the grain of the soundboard oriented diagonally. I think this is a famous builder from the late
1800s/early 1900s (whose name I can't remember at the moment) and (apparently) whose work is highly valued as the guitar went for $330 even its
"reduced" state. In any case I found the diagonal orientation of the grain of the soundboard unusual - as well the bracing pattern which may be
connected to the dynamics of the soundboard grain. Food for thought.
Harry
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Andy
Oud Junkie
Posts: 314
Registered: 10-5-2004
Location: MA
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Mood: excellent
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Hi Harry, looks like a great project for you to work on.
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jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
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The grain direction reminds me of 'acoustic' piano sound board construction where the grain direction in uprights runs at about 45 degrees to the
vertical and in grands at about 45 degrees to the keyboard. Piano bracing is placed diagonally across the grain. Not sure if this is done in pianos to
economise on sound board material (unlikely) or if it has any significant acoustical benefits (longer grain length on average over the sound board
surface perhaps or to deliberately provide longer grain length in certain areas and shorter in others?).
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freya
Oud Junkie
Posts: 276
Registered: 2-8-2004
Location: Asheville NC
Member Is Offline
Mood: Happy in the mountains of WNC
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Not trying to divert discussion here away from ouds only posting when there may be some (distant) applicability...
Yes, I suspect that maximizing the effective grain length over a given area might have some benefit. For guitars, with the larger upper bout, the
diagonal orientation seems like it would increase the total grain length keeping in mind that too much deviation would have a sizable impact on the
flexural modes. For ouds, my instinct tells me that the traditional orientation is more likely to achieve the same result. My calculus is rusty, but
it seems like if one had a mathematical approximation of the shape of the plate, you could use something like a surface integral to figure out the
orientation that maximized the total grain length. Another thing to bug my brother-in-law mathematician about...
BTW, the guitar is probably a "Tilton". Tilton was an "innovative" builder that also introduced the idea of a bar running from neck to heel block
claimed, I think, to provide some enhanced resonance. Didn't seem to catch on.
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