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Old 11-03-2020, 03:52 PM
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iim7V7IM7 iim7V7IM7 is offline
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Join Date: Feb 2012
Location: An Exit Off the Turnpike in New Jersey
Posts: 4,766
Default Selecting a Top

Mark selected some European and Italian Alpine Spruce tops that he thought would work well for my Bristlecone. He joined them and cut them to his Sequoia shape (his largest 16” model).

The photos show the results of his test process and the Chladni numbers for frequencies that he associates with long-grain and short-grain stiffness for each top set. The Sequoia numbers marked with a star are bogus because the top didn’t quite fill the pattern in the lower bout, so the cross-grain numbers are artificially biased higher than they should be.

After recording all the Sequoia numbers, Mark cut all the tops down to his Tamarack size (15-5/8”, slightly larger than the Bristlecone at 15-1/4” across the lower bout) and recorded the Chladni numbers again. All of these tops now appear workable for a Tamarack, so he doesn’t want to cut them all to Bristlecone size. The Bristlecone numbers are predictable at this point given the 3/8” difference in lower bout width.

Out of these five potential top sets, four where appropriate for a Bristlecone (one was too stiff cross grain). Mark and I ended up choosing Set #2 which is an Italian Alpine Spruce set that he purchased from violin luthier David Morse (Soquel, CA) nearly two decades ago (so it is well seasoned at this point). David Morse would visit the famed Val di Fiemme in the Alto Adige region of in Italy to select individual trees for harvest, split, re-saw and ship the processed wood back to the US. This is a well quartered set displaying medullary rays that is likely a AA aesthetic grade top BUT it has the right properties for the guitar being built. It does have a slight a color streak on the treble side upper bout, some of which will obscured by the rosette, covered by the polyester pick-guard and some will be removed by the cutaway.

A bunch of nice archtops, flattops, a gypsy & nylon strings…
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