Research Projects

Lab research focuses on new musical instruments and the study of expressive performance, with a particular focus on extending the capabilities of familiar instruments. Performers spend many years building proficiency on traditional instruments, and whenever a new interface can engage with this existing expertise, the learning curve for a new instrument is shortened and high-quality results can be achieved more rapidly. Goals of lab research include new expressive possibilities for expert performers and composers, new instrumental learning methods for beginners, and a deeper musicological understanding of performance technique.

Magnetic Resonator Piano

[Main Magnetic Resonator Piano Project Page]

The magnetic resonator piano (MRP) is an electronically-augmented acoustic grand piano which places electromagnets inside the instrument to create vibrations in the strings. On the traditional piano, once a note is struck, the performer has no way to modify its sound before it is released. By contrast, the MRP enables the performer to create infinite sustain, crescendos from silence, harmonics, pitch bends and new timbres, all produced acoustically by the vibrations of the piano strings and soundboard. The MRP has been used in performances and installations in the UK, US and Canada, with a growing repertoire of music by 10+ composers.

Visit the main magnetic resonator piano project page for further details and videos.

Selected References

  1. A. McPherson. The magnetic resonator piano: electronic augmentation of an acoustic grand piano. Journal of New Music Research 2010, 39 (3), 189-202. Link
  2. A. McPherson and Y. Kim. Augmenting the acoustic piano with electromagnetic string actuation and continuous key position sensing. Proc. New Interfaces for Musical Expression, Sydney, Australia, 2010. PDF
  3. A. McPherson. Techniques and circuits for electromagnetic instrument actuation. Proc. New Interfaces for Musical Expression, Ann Arbor, MI, USA, 2012. PDF, Design Materials
  4. A. McPherson and Y. Kim. The problem of the second performer: building a community around an augmented piano. Computer Music Journal 2012, 36 (4), 10-27. PDF | Link
    (PDF © 2013 Massachusetts Institute of Technology; archived with permission from Computer Music Journal)
  5. A. McPherson. Portable measuring and mapping of continuous piano gesture. Proc. New Interfaces for Musical Expression, Seoul, South Korea, 2013. PDF

TouchKeys: Capacitive Multi-Touch Keyboard

[Main TouchKeys Project Page]

The TouchKeys project adds capacitive multi-touch sensing to the surface of any piano-style keyboard. Sensor overlays measure the location and contact area of the player's fingers on the key surfaces, and the data can be used to create a wide range of expressive effects including vibrato, pitch bends, timbre changes and improved emulations of non-keyboard instruments. The keyboard is traditionally a discrete interface, measuring notes by onset and release. The TouchKeys let the player continuously shape each note through the subtle expressive details of their finger motion.

Visit the main TouchKeys project page for further details and videos.

Display of finger touch locations on key surfaces

Selected References

  1. A. McPherson and Y. Kim. Design and applications of a multi-touch musical keyboard. Proc. Sound and Music Computing, Padova, Italy, 2011. PDF
  2. A. McPherson. TouchKeys: capacitive multi-touch sensing on a physical keyboard. Proc. New Interfaces for Musical Expression, Ann Arbor, MI, USA, 2012. PDF
  3. C. Heinrichs and A. McPherson. A hybrid keyboard-guitar interface using capacitive touch sensing and physical modeling. Proc. Sound and Music Computing, Copenhagen, Denmark, 2012. PDF | Video Demo
  4. A. McPherson, A. Gierakowski and A. Stark. The space between the notes: adding expressive pitch control to the piano keyboard. Proc. ACM Conference on Human Factors in Computing Systems (CHI), Paris, France, 2013. PDF

Hackable Instruments

[Main Hackable Instruments Project Page]

This project investigates novel design practices for "hackable" digital musical instruments (DMIs), which let the performer deliberately subvert the designer's intentions for creative ends.

Musicians often use instruments in unexpected ways. This is so common that many instruments are primarily associated with performance techniques which were not part of the original design, for example jazz saxophone pitch bends, distortion on the electric guitar, and scratch DJ use of the turntable. Some performers even make physical modifications to their instruments to adapt it to their personal needs.

The "black-box" design of modern DMIs often prevents musicians from making arbitrary modifications or personalisations. The first objective of the Hackable Instruments project is to explore and enhance appropriation in the context of DMIs, studying how design constraints influence the development of unexpected playing techniques. The project also seeks to enable modification (even possibly destructive modification) of the original instrument to suit the performer's personal taste. This component includes the study of prevailing hacking and circuit bending techniques and the design of new DMIs which are specially suited to them.

The hackable instruments are self-contained boxes, using an embedded BeagleBone Black ARM computer running Linux and a new ultra-low-latency sensor/audio platform. Although technology plays a fundamental role in the project, its scientific and artistic contributions are closely tied to collaboration with musicians and music hackers.

This project is funded by the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/K032046/1 (2013-14).

Left: the hardware used for the design platform. Right: a performer playing a first simple instrument designed for the study on appropriation.

Selected References

  1. V. Zappi and A. McPherson. Design and use of a hackable digital instrument. Proc. Live Interfaces, Lisbon, Portugal, 2014. PDF
  2. V. Zappi and A. McPherson. Dimensionality and appropriation in digital musical instrument design. Proc. New Interfaces for Musical Expression, London, UK, 2014. PDF
  3. J. Topliss, V. Zappi and A. McPherson. Latency performance for real-time audio on BeagleBone Black. Linux Audio Conference, Karlsruhe, Germany, 2014. PDF

Piano Touch Analysis

Piano touch is a term often used by pianists to describe the physical gestures of pressing the keys. The sound of a note on the acoustic piano is determined almost exclusively by the velocity of the hammer-string collision, and by extension, a piano performance can be accurately reproduced based only on the velocity and timing of each key press plus the motion of the pedals. However, many pianists devote a great deal of study and attention to the qualities of keyboard touch, examining the physical motions of keyboard technique in ways that go well beyond basic key velocity.

This research project investigates the nuances of keyboard touch by measuring the continuous motion of each key. Our results indicate that while sound production may depend almost exclusively on key velocity, pianists can and do manipulate the motion of each key in several independent dimensions.

Four interrelated but distinct dimensions of piano touch examined in the studies.

Selected References

  1. A. McPherson and Y. Kim. Multidimensional gesture sensing at the piano keyboard. Proc. ACM Conference on Human Factors in Computing Systems (CHI), Vancouver, BC, Canada, 2011. PDF | Link
  2. A. McPherson and Y. Kim. Piano technique as a case study in expressive gestural interaction. In Music and Human-Computer Interaction; Holland, S., Wilkie, K., Mulholland, P. and Seago, A., Ed.; Springer, 2013; Chapter 7, pp. 123-138. Link

Digital Bagpipes

The Great Highland Bagpipe is widely regarded as an instrument with a high barrier to entry. The Highland piping tradition requires the aspiring player to memorise a diverse array of distinct and formally defined ornamentation techniques before attempting all but the simplest of tunes, which can often take six to twelve months of regular and disciplined practice. The aim of this research is to develop technological tools to assist and accelerate this process.

We have designed and built an electronic bagpipe chanter interface which uses touch-free infrared sensing to detect the continuous positions of the player's fingers, allowing the user's performance to be recorded and analysed using specially developed software. The computer program can act as both a solo practice aid to prevent the introduction of bad habits between lessons, and as an illustrative tool to assist an experienced instructor in communicating their feedback to the student in the context of one-to-one piping tuition.

Selected References

  1. D. W. H. Menzies and A. McPherson. An electronic bagpipe chanter for automatic recognition of Highland piping ornamentation. Proc. New Interfaces for Musical Expression, Ann Arbor, MI, USA, 2012. PDF
  2. D. W. H. Menzies and A. McPherson. A digital bagpipe chanter system to assist in one-to-one piping tuition. Proc. Sound and Music Computing, Stockholm, Sweden 2013. PDF

Violin Gesture Sensing

Violin gesture analysis is an active area of study in many research groups. This project aims to capture the nuances of violin performance through a sensor-augmented instrument, with particular emphases on low-latency, economical, portable and non-intrusive setup and applications to new forms of expression in live performance. Left-hand finger locations on each string are measured by resistive material on the fingerboard. A new method of bow position and pressure tracking has been developed based on low-cost optical reflectance sensors. One eventual aim is to produce a new expressive interface using expert violin technique to control other sound sources.

Selected References

  1. L. Pardue and A. McPherson. Near-field optical reflectance sensing for violin bow tracking. Proc. New Interfaces for Musical Expression, Seoul, South Korea, 2013. PDF
  2. L. Pardue, D. Nian, C. Harte and A. McPherson. Low-latency audio pitch tracking: a multi-modal sensor-assisted approach. Proc. New Interfaces for Musical Expression, London, UK, 2014. PDF

EMvibe: Electromagnetically Actuated Vibraphone

[Cameron Britt's EMvibe Project Page]

The EMvibe is a collaborative project with Cameron Britt and Jeff Snyder of Princeton University. The EMvibe generates new sounds from the bars of an acoustic vibraphone. A small magnet is affixed underneath each bar, and electromagnets induce the bars to vibration. The resulting sounds resemble a bowed vibraphone in purity and sustain, but with greater control possibilities. Individual harmonics (1, 4 and 10) can also be elicited from each bar. The EMvibe electromagnetic sounds can be used simultaneously with traditional playing and can be activated based on the bars the performer strikes.

Demonstration of EMvibe techniques

See also: Ctenophora for EMvibe and three laptop performers by Cameron Britt. Score and video on Cameron's project page.

Selected References

  1. N. C. Britt, J. Snyder and A. McPherson. The EMvibe: an electromagnetically actuated vibraphone. Proc. New Interfaces for Musical Expression, Ann Arbor, MI, USA, 2012. PDF