Electronic Musician * June 1998 * by Bean

Tech: A Soft Touch


Imagine creating a sound collage by waving your arm. With a flick of your wrist, the pitch modulates, and when your fingers bend, the notes' duration changes. The voice changes entirely at the touch of a fingertip. Playing meaningful, melodic or rhythmic musical arrangements in this manner requires a state of awareness that allows instantaneous action and reaction to every sound and motion you make.

Although it may sound futuristic, this technology exists today in the Lady's Glove, developed by French composer Laetitia Sonami with the sponsorship of the STEIM Institute (Studio for Electro-Instrumental Music). For Sonami, the physical experience of making music is an integral part of the performing and composing process.

A brief history of airplay. In the early 1980s, Tom Zimmerman wired up a cloth glove that, when used as an input device to control the onboard synth in an Atari computer, allowed him to play air guitar. A few years later, Zimmerman and Jaron Lanier invented the DataGlove by adding tracking devices to this controller. Their company, VPL Research, patented and manufactured the hand-gesture recognition device for controlling computer interaction. The DataGlove sold for approximately $8,000.

VPL also licensed the hand-gesture recognition technology to Abrahms Gentile Entertainment, which in turn worked with toy maker Mattel to create the Mattel PowerGlove. After Byte magazine published the "secret" pin-outs of the $89 PowerGlove, it wasn't long before musicians were experimenting with the high-tech toy to explore new ways of making music.

From latex to Lycra. Around 1991, Laetitia Sonami developed electronic gloves made of latex rubber, similar to the gloves you may have used to wash dishes. Sonami glued Hall Effect sensors onto the fingertips and a magnet onto the thumb so that when her fingers touched the magnet, a signal was generated. She used a converter to derive MIDI information from this analog signal, which allowed her to trigger sounds. (Hall Effect sensors are a product of American Electronic Components, Inc., a manufacturer of custom sensors, industrial switches and relays, and other electromechanical devices.

Finding Mattel's inexpensive PowerGlove big and bulky, Sonami decided to create a lighter, more responsive controller. The name "Lady's Glove" was meant to be more of joke that a fashion statement, but on stage it's the ultimate in cyber haute couture.

In collaboration with Bert Bongers, Sonami tailored the Lady's Glove of fine Lycra mesh. The skeletal framework of the glove is composed of turquoise blue plastic rods. All the wiring and circuitry is exposed; ribbon cable runs the length of the performer's arm, connecting to microswitches embedded in the glove's fingertips. Many of the Lady's Glove's resistance strips and components originally came from cannibalizing a Mattel PowerGlove, to which Bongers and Sonami added ultrasound, pressure, and motion sensors.

Using ultrasound emitters and receivers to decorate her shoes and pad the palms of the gloves, Sonami is able to modulate pitch as a function of the distance between her hands. As Sonami changes the distance from her hand to the floor, the length of the beat cycle is modified in real time. A miniature circuit board that was originally designed to launch emergency airbags in automobiles detects speed and motion, producing a variable voltage from Sonami's gestures that gets converted into audio.

Mysteries revealed. On the inside of the glove, Hall Effect sensors produce varying voltages that correspond to a preprogrammed set of algorithmic probabilities created in Opcode's MAX, an object-oriented programming language. Sonami uses MAX to set a threshold so that whenever her fingers pass a certain distance, they trigger an immediate response. That way, she doesn't have to actually press a mechanical switch. According to Sonami, because of a response limitation of two inches, the Hall Effect devices are difficult to use if you want to measure distance, but they work well for switching.

STEIM's SensorLab analog-to MIDI converter beltpack translates the electronic and ultrasound signals into MIDI data and relays them to a computer on the side of the stage. Sonami also uses the SensorLab to tune the sensors' voltage regulation, response time, etc., and to channel them to whatever MIDI controller numbers she needs.

For years, Sonami has been using a Macintosh Powerbook 180 and MAX to handle all the music programming. For example, she wrote an editor to control the parameters of her synthesizers as functions of her movements. She recently upgraded to an Apple Power Mac G3 with MAX, Cycling 74's MSP, and a Korg SoundLink DRS 1212 I/O card. This new system will eventually be the source for all of her sampled, FM, and additive synthesis sounds.

Harnessing reality. Coordinating the numerous muscular combinations necessary to master the Lady's Glove is no small feat. Playing in tune requires the concentration of the entire body, with continual motion adjustments for fine-tuning. Sonami gracefully choreographs her unique hand-dance creations, inspired by a cross between East Indian singers and sign language. Watching her constantly adapt to the music she makes, you can clearly see that every composition requires a balance of prearranged physical movement and spontaneous improvisation.

Sonami's performances interleave sonic layers of industrial, ambient, and rhythmic textures with spoken work to form a provocative, transformative journey. Her on-stage freedom is made possible by the programming of parameters she determines with the computer beforehand. By establishing the relationship between the gestures and the sounds in the software, she is able to listen, shape the sounds, and feel as if she is modeling the air in performance.

Sonami admits that the glove has its share of limitations, but like any other instrument, once you learn to use it, these limitations become part of your musical vocabulary and expression. Ultimately, Sonami hopes to transcend technology altogether for both herself and the audience.