Bumblers use rubber bands as free reeds to create a humming or buzzing sound. The instruments are laser cut from wood.
I prefer to use #64 rubber bands. Different sizes will alter the pitch and timbre.
The basic Bumbler design allows the user to specify the number of rubber bands. Adding wax paper to the instruments changes the timbre and volume.
A two-piece design that allows multiple configurations. I prefer to assemble these with one cross piece furthest from the string attachment. This puts more weight toward the bottom of the instrument and allows it to swing easier. These bumblers will often rotate rapidly around their long axis, producing an interesting modulated sound.
The ‘mortiseWidth’ and ‘mortiseTolerance’ values may need to be adjusted based on the thickness of the material you choose.
The tri-bumbler requires some assembly. Cut 3 pieces for each tri-bumbler. The tenons fit into the central holes to hold it all together. A bit of wood glue between the pieces and around the tenons will help hold it all snug. The ‘mortiseWidth’ and ‘tolerance’ values may need to be adjusted based on the thickness of the material you choose.