The Universal Language Orchestra is continuing into this fall with a new grant from UCIRA! As part of our proposal, we have been coming up with musical ideas and instruments to stimulate our young (8 - 12 year old) students' imaginations. This summer, my role has evolved into research and development of these instruments, with the intention of breaking down the expectations and implicit hierarchy concomitant with traditional instruments.
To this end, Adam Tinkle and I have come out with designs for a very inexpensive mbira, or "thumb piano", which can be easily amplified and otherwise extended to include all sorts of other sound-making possibilities. While the prototype demonstrates something very similar to a traditional (albeit non-Western) instrument, we see this as a platform on which to extend into further sonic zaniness and fun.
An mbira (kalimba, marímbula, thumb-piano, etc) is a lamellophone, a class of instruments that make sound via an array of plucked metal tongues. By "plucked metal tongue", I mean something similar to the tab on an opened soda can, although in general these instruments are much more expressive. They have been widely used in African and Caribbean musics for uncountably many centuries. Pilfering the idea for our own ends, we decided to figure out if we could build one for less than $10 per unit. We succeeded! You can too:
Parts list :
NB these are Home Depot prices, and, with all due respect to them, you may find cheaper hardware at your local shop. We certainly did. Also, smaller stores will let you try out the hardware to make sure everything fits correctly, which is absolutely essential when buying nuts & bolts.
14-terminal ground bar - about $3.00 each
2 carriage bolts - about $1.00 each
4 hex nuts - about $0.35 each
2 wing nuts - about $0.50 each
some sort of wood for the body - we spent $1 or so
bobby pins - $1.00 for a pack of 60
I don't have photo documentation of each step, but I trust you can use your imagination. Also, a side view of the finished product might help you see the big picture:
If you'd like to make your own, the trickiest part is making the bridge, where the tongues are coupled to the rest of the instrument (we used pieces of wood as a body). The best material for this bridge is an electrical ground bar. A 14-terminal bar can be had from Home Despot for a mere $3 or so. This will give you 12 slots into which you may insert the tines, or anything else your heart desires (we were thinking springs might be nice . Sitting in each terminal is a screw which clamps onto whatever you put into it. Take out the first and last screws, and carefully drill out those holes. Make sure these holes are straight, or you'll have a tough time getting the body fastened to the bridge.
There are two schools of thought about how to get a snug fit with a bolt. The one I subscribe to -after some particularly difficult experiences- is that you should use the materials themselves to measure where to put the holes. Sure, take a measurement, and mark up your piece of wood, but in the end it comes down to the angle your drill took as it bored the holes. Therefore, after measuring, I took to clamping the bar onto the piece of wood with two c-clamps and drilling into both pieces in one fell swoop. This will not save you if you take it at an angle, so be very careful! I'm probably laboring this point a bit too much...
Then slide the bolts through the end terminals, and thread a hex nut around the bottom of each, clamping them to the bar. You can use whatever length of bolt you'd like- we went for longer ones because we wanted tongues to vibrate with a lot of action. Use 1/4" bolts, or whatever will match your drill bit.
Next, you want to thread two more hex nuts onto the bolts. These will press down onto the body while allowing as much distance from the tines as you would like. Try to make them somewhat even, although you can correct for any error once you have the board on there.
Now it's time to fasten the bridge onto the body. Use the two wingnuts for these last two points. This will let you manually re-tighten the hardware, which you will definitely need to do at some point. Tighten the top nuts onto the body as well, so everything fits snugly. You may experience some weirdness if your drill came through at an angle. I had no problems here that a little elbow grease couldn't solve.
Now, for the tongues. Our pictured mbira actually uses poly-coated metal rake tines, which we cut off a $20 rake. This will drive up the cost of your mbira, although not by very much, since you can get a lot of tines out of a single rake. However, after a little experimenting, we found that bobby pins actually sounded better! A pack of these can be had for a song. And although our rake tines are coated in poly, some of them still are a bit sharp, so honestly for the kids we're most likely going to stick with bobby pins.
Another drawback to rake tines- they're pretty tough to get off the rake!
And that's basically it! For amplification, I soldered a 1/4" jack onto a piezo element and epoxied it to the board. I am strongly considering making magnetic pickups so we can avoid amplifying contact noise, but then again sometimes contact noise is a good thing. Also, 4,000 turns of wire per pickup, at one pickup per tine, and twelve pickups per mbira... that's a lot of turns of wire. If we went with something like that, it would likely be done with a servo motor / microcontroller setup for automation purposes. I'm looking into it and will report back!
Enjoy the noise! ^_^