Polar Suite

String Quartet for augmented instruments and field recordings.

  • Dates: 2001
  • Location: Berkeley, CA
  • Role: Developer
  • Collaborators:
    • Doug Quinn – Composer
    • Keith McMillen
    • David Harrington – Kronos Quartet
    • John Sherba – Kronos Quartet
    • Hank Dutt – Kronos Quartet
    • Jeffrey Zeigler – Kronos Quartet
Polar Suite 1
Polar Suite 2
Polar Suite 3
Polar Suite 4
Polar Suite 5
Polar Suite 6

“This is an opportunity to essentially relearn our instruments and to transform how we approach live performance. “Polar Suite,” is a very different kind of string quartet and an extraordinary sonic adventure–thanks in large part to the K-Bow and what is now possible!” – Kronos Quartet founder David Harrington

Composer Douglas Quin’s Polar Suite, performed by the Grammy award winning Kronos Quartet, is driven by the Keith McMillen Instruments K-Bow system. The piece is the result of a weeklong residency by the group culminating months of work developing a groundbreaking musical experience that couples the world’s most adventurous string quartet with cutting edge technologies.

The K-Bow is standard string instrument bow augmented with a variety of sensor technologies to bridge the gap between traditional musical performance and the possibilities of computers. The sensors integrated into the carbon fiber bow detect detailed data on every aspect of a string player’s performance and send it to a laptop computer via Bluetooth wireless. Once there, a suite of custom software uses that data to control audio effects, sample playback, surround sound, or video. The Kronos Quartet was outfitted with a entire quartet of these bows, one for each member, providing a foundation for interactive sound creation over the whole ensemble.

Composed by Douglas Quin, hailed as the “Audubon of Audio” by the Washington Post, “Polar Suite” integrates the sounds of traditional instruments processed with captured sounds all controlled by movements of KMI’s K-Bow. The piece was commissioned by Kronos and features soundscape recordings from the polar regions of the earth and outer space plus additional processed samples.

The Kronos Quartet of David Harrington, John Sherba, Hank Dutt, and Jeffrey Zeigler has pursued a singular artistic vision, combining a spirit of fearless exploration with a commitment to expanding the range and context of the string quartet, for more than 30 years. Kronos has become one of the most celebrated and influential groups of our time, performing thousands of concerts worldwide, releasing more than 45 recordings of extraordinary breadth and creativity, collaborating with many of the world’s most eclectic composers and performers, and commissioning more than 750 works and arrangements for string quartet. In 2011, Kronos became the only recipients of both the Polar Music Prize and the Avery Fisher Prize, two of the most prestigious awards given to musicians. No other musician or ensemble has ever won both prestigious prizes, let alone in a single year. The group’s numerous awards also include a Grammy for Best Chamber Music Performance (2004) and “Musicians of the Year” (2003) from Musical America.

The K-Bow was the flagship product of Keith McMillen Instruments, a Berkeley, CA based company producing advanced technologies bridging the gap between traditional ensemble music performance and the collaborative information processing machine that is the computer. It measures a number of axes of control, including:

XYZ 3D Accelerometer – measures the playing force and angle of the bow Hair Tension Sensor – detects how hard the bow presses against the strings Grip Pressure Sensor – gives a measure of how hard you are gripping the bow Bow to Fingerboard – a measure of the distance you are playing from the fingerboard via the antennas embedded in the bow Bow Length – by interacting with the included fingerboard emitter, an infrared light sensor shows the distance from the bow frog to the strings of the instrument Bow Tilt – measures the angle of the bow, useful to know which string is being played By enabling the string quartet to access the unlimited sound world of the computer, the K-Bow advances western art music to places never before possible, and allows the interpretation of electronic scores by multiple ensembles. Complete with integrated software, the K-Bow applications feature sophisticated DSP processing that allow performers to process their sound, recording multitrack loops, control surround panning, and communicate with other software; all from their familiar instrument.



  • November 9, 2011 - College of Visual and Performing Arts at Syracuse University.