Basically, I'm planning on building a dulcimer-like instrument for a concert of experimental music that we have planned for later this year. The instrument originally used to play this music was built in Mexico in the 1930s and now sits in a museum. Since I don't have access to it (other than a handful of pictures and some very basic measurements), rather than trying to copy that instrument (which would involve a lot of guessing), I'm designing one that follows the same basic layout, but that is a bit closer to what a hammered dulcimer design. Here are the key differences between this instrument and a regular HD:
- This is a microtonal instrument in 1/16th of a tone (i.e. 16 subdivision between C and D, and it takes 96 strings to play a full octave)
- The strings will be plucked, like a psaltery instead of being struck by hammers
- Because of this, the strings will run vertically rather than horizontally
- The instrument needs to produce 2 octaves (C4-C5 and C5-C6)
- The instrument will have 97 (96 subdivisions + octave on top) single course strings, spaced 1 cm apart
- There will be a single bridge located 1/3 (2:1 ratio) of the way between the top and bottom nuts to get the two octaves
- Because of the limited range, the shape of the frame will be rectangular rather than trapezoidal (about 40" wide, 25" tall, about 3-3.5" high)
- The pin blocks will be made of hard maple; rails and braces of 3/4 plywood to minimize wood movement; top of 1/4" ply
- Given the number of strings, a 3/4" bottom glued and screwed/doweled to the pin blocks would seem prudent, but it is going to make for a heavy instrument. Would a better alternative be to use some internal braces in between the pin blocks (with some holes drilled through to allow air movement) and a 1/4" back?
- If I go with the internal brace option, would taking the braces all the way up to the top (rounding the part of the braces that would touch the soundboard) offer enough support for the soundboard, event though the braces will be perpendicular to the bridge? An alternative could be to make the braces shorter and then place a cross support piece that would fill the gap between the braces and soundboard and that lies parallel to the bridge
- Could anyone offer any advice on sound holes (size, location, number, bracing requirements)?
- I'm leaning towards a floating soundboard, but I'm wondering whether some of the construction options mentioned above would work better with a glued sound board. I have not been able to find as much information about HDs with glued tops, so I'm fuzzy on the pros/cons of each.
