Two Simultaneous places - or How To Fold a Vibrating Wire in Three...

The setup here is this: four lengths of fine piano wire, strung from one end of a room to the other (about seven or eight metres). A piezo transducer picks up vibrations at one end, which are amplified through a speaker at the other. This has an old super-8 film canister lid on top of the cone, over which the strings pass, and which acts as a bridge. Several cheap laser-pointers shine across the strings to the opposite side of the room onto some photodiodes, which convert the flickering light into a voltage, which is then treated as sound. The sound in this video is a mixture of the photophonic and acoustic outputs from this mechanism.
I'd been wanting to buid a long-string instrument for quite a while, but hadn't got around to doing it. The original plan was to play the strings with rosined fingers Paul Panhuysen style, but it quickly became apparent that the pressure you need to exert on the string to get it to sound deflects it by around 20 to 25mm. This meant that the lasers I'd set up would miss the thing almost entirely. So I said goodbye to Panhuysen and hello to Alvin Lucier with the aforementioned speaker/piezo setup; somewhat crude, but it got things buzzing nicely.
Using the lasers in this way, it's possible to isolate points and amplify them independently and with no effect on the string, in a way that is impossible with mechanical methods. You might then surround a listener with these sources, wrapping the vibrating string into a circle. It doesn't sound like a string for the most part; it just is what it is, but I like that.
This particular piece is the result of a week's residency I've just finished at PVA MedliaLab in Bridport, Dorset. Thanks must go to PVA for inviting me, and to Duncan Whitley for his support - both moral and practical - and also to Andrew Hinton.