OK guys. I need a bit of mad experiment know how and ideas..
Has anyone made any bowed instruments?
I would like to make a cello type instrument and about the only thing I know about all this is that at the basic level the string curvature is quite rounded (so that the bow has enough clearance to effect the strings one at a time).
Has anyone in this group produced any noise from anything in this way? If so, how is it done without all the finesse of going out and buying one of these things to strip it down.
Replies
Go for it, it can't be too different from building a git.....
Violin, Viola, Cello, Upright/Double Bass are all built the same way.
1. the narrow waist, excessively tall bridge, severe back-angle and break across the bridge to the tailpiece are all so that the strings are in a position so that the bow can play one at a time. the bow does have some flex in the hair and pressing hard enough you can hit 3 strings at once, but it's not good for the bow. light bow pressure for a soft sound and firm bow pressure for a loud sound need to be allowed for. a little googling found the radius for the end of a cello fingerboard should be between 64 and 70mm, the string height at the nut a hair less than 1mm, at the end of the fingerboard 6mm for the high pitch string, 8mm for the low pitch string.
So, give it a really good break angle over the fingerboard, a tight radius to bow one string at a time, and room to not hit the body of the instrument with the bow.
2. violin/viola/cello/bass make sound the same way a CBG does, the strings vibrate and the bridge conducts that to the soundboard/face/belly of the instrument, reverberates around in the empty space, bounces off the back and comes out the sound holes.
sounds easy enough
3. Because of the very tall bridge, severe back-angle, and break angle over the bridge of almost 30 degrees, the face/belly/soundboard of a violin/viola/cello/bass takes a LOT more pressure than an acoustic git, so thery are braced with a bass bar on the bass side, and a soundpost on the treble side.
the soundpost is a dowel that is wedged between the front face and back face of the body to stop the extreme pressure from crushing the face (like a jack stand keeps a car from crushing your chest when doing an oil change) it's placed near (tailward and outboard a little) the treble foot of the bridge. it's not directly under the bridge so that it doesn't kill the sound from that side.
the bass bar is a brace (like the bracing on the soundboard of a guitar) under the bass side of the bridge, running longwise to give the soundboard strength but allow more vibration than the soundpost side.
so just make sure the soundboard doesn't collapse under the pressure.
SO really all you need to do is give yourself some space for the bow and don't let the string/bridge pressure crush the soundboard, all else is open to your creativity.