Have you ever wanted to play an instrument designed by a blue, two-headed, guy from a Star Trek re-run:an instrument that uses light in place of strings? Of COURSE you have because then you could be like Captain Kirk (or Mr. Spock if you a less demonstrative and more thoughtful type).

Peter DeSimone, as far as we know, is not now (nor has he ever been) a crew member on the Starship Enterprise. Nor is his skin blue. He also appears to have the normal number of human heads. Nonetheless he has created such an instrument. And he took some time to chat with Gearwire about it.

Tell me what the light harp IS in simple terms. It seems like a sort of light based theremin but without the UFO sounds.

Yes, a light harp bears some resemblance to a theremin, but there's a critical difference (beyond how it physically accomplishes the proximity detection); a theremin is a monophonic instrument that allows the performer to control the pitch and volume of a single note. A light harp, on the other hand, is a polyphonic instrument that allows the performer to play multiple notes at once, since each "light string" acts like its own separate instrument. As with a traditional harp, each string creates its own note.

Tell me about the principles behind this instrument?

Well I suppose light harps have been around in one form or another since the very first electro-nerd had the idea to plug a photosensor into some kind of buzzer. Some of them play a note when you "break" a beam or cast a shadow, like when you walk through the door at the Kwik-E-Mart. Others bounce light beams off your hands and use the faint backscatter to trigger notes. Each has its own set of pros and cons. Without going into too much detail, a "shadow harp" can detect objects at a potentially greater distance, but a backscatter harp offers proportional dynamic control that the former does not.

All the instruments I'm currently working on are MIDI controllers. They just send "note on" messages to whatever arbitrary hardware or software you want to use to perform the synthesis. This allows me to focus on improving the human interface without having to worry about the entire other half of the coin.

How easy is it to play? What sort of musician is going to have the easiest time with it? What sort of background lends itself to this?

Since I'm developing light harps mostly for song-writing and vocal accompaniment, I've been focusing on using them to trigger chords. My favored system at the moment involves using 7 light strings, each keyed to a separate diatonic chord. Most popular music is composed mostly or entirely of diatonic chords, so I would say for the average person with little or no musical background, it would be a lot easier to play a popular song on a light harp than on a guitar or piano (on the light harp, each of these chords can be played by simply holding out your hand).

Since many songs use modulations (chords outside the key of the song), I made the 7th light string double as a modifier that, when played in conjunction with any of the other six, converts the desired chord into its parallel major or minor. This allows easy access to the "II" and "III" chords so often employed by The Beatles and countless other songwriters throughout history. So with immediate and intuitive access to 13 chords (7 "primary"/diatonic + 6 "secondary"/modulations), I would have to say that I don't know of any polyphonic instrument that's easier to play. Even as someone fairly proficient on guitar and piano, I find myself using the light harp for song-writing purposes and to analyze the chord structures of popular songs. That's what I would consider to be the light harp's ideal application.

How easy is it to integrate into, lets say, a live performance? Will live sound engineers around the world soon be calling for your head?

It's as easy as any other electronic instrument, with the exception of the fact that since light is used to detect the performer's gestures, there's always a possibility of interference from extraneous light sources. I think this would be a task for the lighting technician more than the sound engineer. The pulsed LED differential backscatter system I cooked up seems highly resistant to such interference, though. Unlike most backscatter light harps I've seen, ours will function in a well-lit room without any problems.

(in other words, sound engineers WILL be calling for his head-editor)

Talk to me about amplifying this in a live setting?

It's as straightforward as amplifying a synthesizer keyboard, since at the moment the light harp is a MIDI controller. Your audio will be coming from either a laptop or a synth module, so it'll be standard line-level stereo either way.

What about the studio? Talk to me about recording w this light harp?

The same principles apply to recording a light harp as any other MIDI instrument. My preferred method is to record the MIDI note data rather than the audio, so I can edit the performance later if necessary, change instrument patches and all that good stuff. When I recorded Anna Coleman for instance, I later changed the Logic patch to a different choir sound and added a second patch at a lower volume to create a subtle effect. The light harp has its own arpeggiator, but for recording purposes I would recommend using a software arpeggiator instead so you can change patterns after the fact.