Electromechanical devices are beginning to appeal to me greatly; I’ve been flicking through PDFs of Telephony volumes 1 and 2 by J. Atkinson, and the combination of mechanical and electronic methods is fasctinating.
For the next portfolio project I’ll be aiming to create a synthesiser that acoustically excites resonating bodies, as opposed to the classical model of generating AC voltages to excite a speaker cone. Some may argue that the core essence of a synthesiser is the creation of tones in an electronic fashion (be it analogue or digital) and thus physically excited acoustic objects do not fall under the category of a synth, but I am making a claim that all synthesisers have to eventually excite some resonating body to be percieved as sound, and consequently my concepts can be described as synthesisers due to the resonating bodies being excited by electronic means.
I have been drafting ideas for the past few weeks; below is a scan of my notebook showing some of the designs that have been conceptualised. All are planned to operate using some combination of motors and solenoid actuators; so far these are the only two electromechanical devices that I’ve designed with, but other ideas are starting to grow using acoustically noisey relays, or perhaps piezos?
Motors with objects attatched to the shaft present an opportunity for continuous and repetitive beats, like crochets. Solenoids, however, present an opportunity for more complex rhythmic ideas involving simple sequencers using CMOS chips such as the 4017 decade counter IC, or other more complex chips like the 4516 IC which can count both upwards and downwards (similar to the sequencer module in the Serge unit at uni).
Top left of the scan (fig. 2) depicts two designs. The uppermost design is similar in form factor to my last project (which dissuades me from proceeding with the design), and operates by exciting a row of objects with motors or solenoids. Controls for sequencing the solenoids and altering the rate of the motors exist on the front panel, with objects on the top. Objects I would like to use include wood, rock, metal and ceramic.
The device in the lower half of the image, housed in a rectangular case, is a device that excites ceramic plates with solenoids. I have a friend who makes ceramics, and I am considering asking her to create some plates for me similar to those on a glockenspiel or xylophone. I am assuming that by using a mass of clay that is proportional from one to the next, i.e 10g, 20g, 30g, that the pitches produced would be also proportional.
In the lower left part of the image (fig. 3) a third device is shown, one which explores a more continuous form of sound genesis. A cylindrical glass jar is slowly rotated by a DC motor, the rate of which can be altered either with a knob or, if the design process trends this way, modulated with a variety of low frequency oscillators. Pebbles are placed inside the jar, but a variety of other objects can be used, pebbles just seemed to be an appealing choice to me. This design appeals to me as the exact rhythmical outcome is random, but the use still has control over the flavour of the sound.