Wednesday, March 7, 2012

Ongoing Sound Experiments

Tube Zither 

This is our attempt to replicate a Valiha, a type of zither from Madagascar usually made using a piece of bamboo.  We pre-drilled small holes in a piece of abs pipe we had laying around and used wood screws and eye screws attach the strings just like in the canjo. We put a small pieces of wood on the point of the screws were sticking into the pipe (not visible) and used similar small blocks of wood with grooves in them to function as bridges.  The first test produced a soft but clearly audible sound, that could be adjusted by moving the bridges, tightening or loosening the strings or figuring them like a guitar.  As the tube functions as both the resonator and the neck of the instrument its a very simple and versatile.  We will try to make a more standard model employing a cardboard tube in the near future and will post instructions when we do.  

Tube trumpet

Some times referred to as a Hosaphone, there are hundreds of different examples online.  That said we don't claim to be doing something new here, but instead were trying to figure out the nuances.  We started with 28'' of 5/8'' and 67'' of 1/2'' vinyl tubing and then started changing the mouth pieces and horn bells to see how it would effect the sound.  With out any modifications we were able to get 5-6 tones out of the trumpet consistently.  Below are some of the horn we tried:

the 3/4 2 liter resulted in a clear but muffled tone, the water bottle was buzzy and had the added feature of being squish-able which sounds sort of like a mute on a trumpet, the vitamin water bottle sounded very much like a stadium horn (Vuvuzela) and the straight cone made the clearest tone. The 3/4 2 liter seemed to make playing hight notes difficult.

Here's the tube with a mute (a 2 liter bottom) and some mouth pieces we tried. The small section of larger vinyl tubing as a mouthpiece is playable, but a small section of pvc worked better, but not great.  Given the success the pvc we tried boring out the inside of a identical pvc pipe to make the opening bigger, this resulted in an even more playable mouthpiece. I noticed that you could get higher notes more easily with this mouth piece.  Hoping this trent of wider and stiffer would be better we tried gluing the very top section of a 2 liter to a pvc pipe to make a super wide mouth piece, this was did not work as planed.  The horn was very easy to sound, but getting high notes was nearly impossible, as you couldn't close your lips tight enough with the wide opening .    
Given the surprising variety of results planning an activity based on making a curtain timbre (character of sound) with a tube trumpet or similar instrument might be possible in the future.      

Sound Automata: Drum Machine

   This is our first attempt at programable sound automata, a drum machine.  It consists of a cardboard tube you can rotate with a crank, into this drum you can add tacks at various intervals to strike the drum sticks and create a rhythm.

Here's the automata in action playing on a tea tin (sorry for the uninspired rhythm).
We plan to develop a few standard models of this and post them in the future, stay tuned.

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