Sluicer (2023-curr.)

SFFX (2022-curr.)
Quarries (2016-22)
Sifting (2018-21)
Outwash (2019)
Rhythm Studies (2017-18)
Substitutions (2015)
Missents (2015)
Multipass (2015)
Emerald Tablets (2014)
10K Descents (2014)
Impellent (2012-14)
Locks (2013-14)
Adder (2012-13)
Sieves (2011-12)

Selected discography


Shawn Greenlee is a composer, sound artist, and Professor at Rhode Island School of Design (RISD) where he leads the Studio for Research in Sound & Technology (SRST).  His recent work explores spatial audio, high density loudspeaker arrays, and erratic sound synthesis techniques.

Greenlee has been active as a solo electronic / electroacoustic improvisor since 1997 and has toured extensively across the US and Europe. Conference and festival performances include New Interfaces for Musical Expression (2018 Blacksburg, 2015 Baton Rouge, 2014 London, 2013 Daejeon), International Computer Music Conference (2021 Santiago, 2018 Daegu, 2011 Huddersfield, 2005 Barcelona), BEAST FEaST (2017 Birmingham), PdCon16 (2016 New York), Cube Fest (2019, 2016 Blacksburg), Re-new (2013 Copenhagen), IN TRANSIT (2008 Berlin), and Elevate (2007 Graz), among others.

Greenlee’s solo and group discography spans over fifty releases. He is a founding member of Landed, active since 1997 and known for its deconstructed rock, rhythmic noise, and intense live performances. From 1999-2001, he performed with Six Finger Satellite.

Greenlee holds a Ph.D. in Computer Music and New Media from Brown University

Sluicer (2023-curr.)

Sluicer is a performance system for spatial audio improvisation, adaptable to various output channel configurations from stereo to high density loudspeaker arrays. In this work, two 20-voice, erratic synthesizers operate as a roving “chorus” under the player’s direction. Both synths have a series of multichannel effects designed to work specifically with high order ambisonic signals, allowing the player to create and alter spatial dimensions. As audio flows, the guiding action is like closing/opening gates in a lock on a waterway. The results are timbral and spatial churns, swells, floods and drains, motion in repetition, expansion, and contraction. Sluicer is programmed in Max with tactile interfaces being high resolution, multi-touch control surfaces and a DJ-style MIDI controller.

SFFX (2022-curr.)

Work in progress

Since 2015, my artistic work and research has been primarily focused on an area within spatial audio involving High Density Loudspeaker Arrays (HDLA) which are typically permanent installations with 24 or more loudspeakers in a cube or hemispherical configuration. Some HDLA facilities feature arrays with hundreds of loudspeakers to provide more resolution and precision, and to support a wider range of spatial audio techniques. For this work, I have traveled to various HDLA facilities to participate in residencies and workshops and to perform/present at conferences and festivals. In 2018, I founded at RISD the Studio for Research in Sound and Technology (SRST) which houses a 25.4 channel loudspeaker array. I serve as Faculty Lead for SRST overseeing its staff, curriculum delivery, research advancement, and public engagement.

A prevalent technology for creating immersive audio experiences in HDLA facilities, SRST included, is High Order Ambisonics (HOA). 

In 2021-22, I was the Project Director for a NEA grant-funded software development project that provides proof of concept for my new work in spatial audio going forward. An outcome of this work is FOAFX, a command line tool for applying spatially positioned audio effects to first order ambisonic sound files. It is currently available as a Node.js program, including source code. With this project complete and a wealth of preliminary research accomplished, I am now building on this work to create “SFFX.”  SFFX is a new, multiyear software development project with the goal of producing an open package for 3d audio effect processing intended for sound designers and composers working with High Order Ambisonics (HOA). Because SFFX employs HOA in its approach, the outcomes will be scalable to a variety of loudspeaker systems, as well as to stereo headphones through binaural rendering.

SFFX aims to solve a problem encountered in audio workflows involving ambisonics, wherein several audio effect processes, (e.g. compression, distortion, noise cancellation) cannot be used with encoded 3d audio without ruining the spatial dimensions of the source file or stream. While there are some workarounds known within the 3d audio community, these methods involve combining several tools and complex signal routing which can be puzzling, detering most users. The goal is to apply an effect to the entire sound field or a region within it without entirely losing the 360° fidelity. An exciting affordance provided by the SFFX approach is that a spatially positioned audio effect can be automated to move through the sound field, resulting in a dynamic spatial wet/dry effect mix which can provide a wellspring for creativity. As a practical example, similar to a spotlight tracking a performer on a stage, SFFX could be used to focus in and increase the gain of a moving sound source while suppressing background noise. 
Further SFFX will offer several unconventional methods for altering 3d audio through a process I have termed, Sound Field Displacement (SFD).  

SFD relies on the polygon configurations that underpin HOA for virtual microphone/loudspeaker positions whereby each vertex represents an individual audio channel in the 3d decoding/encoding scheme.  With SFD, these vertices are repositioned in uniform ways to create rotations and transpositions or nonuniform ways to create spatial artifacts and discontinuities, offering new immersive qualities.

︎︎︎ 3d point, polygon, and energy vector representations of octahedral octahedral (6-channel) ambisonic coding

︎︎︎ Energy vector visualizations of Sound Field Displacement, 6-channel

︎︎︎ 3d point, polygon, and energy vector representations of octahedral (20-channel) ambisonic coding

︎︎︎ Energy vector visualizations of Sound Field Displacement, 20-channel
For SFD, I have created a link between color models and HOA exploring shared usage of spherical and cartesian coordinate systems.  For instance, 3d color models such as Hue, Chroma, Luminance (HCL) can be mapped as XYZ spatial positions to place virtual microphones/loudspeakers for the HOA process.  This repositioning of vertices based on color data gives composers a new means to graphically score or automate spatial parameters, thus providing an alternative to inadequate standard music notation systems and software compromises such as timeline-based, breakpoint editors. Furthermore, real-time visualization based on spherical coordinates (azimuth and elevation) is another aspect where salient color models can be applied to support sound design and musical analysis.

Sifting (2018-21)

In 2018, I was awarded a Polar Lab Residency supported by the Anchorage Museum. My project was titled Edges in the Alaskan Soundscape. Over the course of three weeks in April / May 2018, I concentrated on spatial audio field recording in areas of the Kenai Peninsula and Denali National Park. During this timeframe, alongside field work, I met with National Park Service scientists to learn about acoustic monitoring and soundscape ecology from their perspective as researchers. The aim of my project was to conduct ambisonic field recording in areas with low human population density in order to observe and document “edges” while creating source material for new compositions and sound installations. Sifting is an outcome of this work. It debuted as a 4-channel sound installation for the Listen Up exhibition at the Anchorage Museum (April - October 2021).  It was composed in third order ambisonics and may be presented on larger speaker arrays.  A stereo mix is provided on this page.

In my field work, edges recurred thematically as:
  • A spatial relationship, areas between the built environment and natural land
  • A seasonal timeframe, the period between winter (ice break-up) and spring
  • A practical situation, what was manageable for solo expeditions in difficult weather and terrain
  • Ecotone, a region of transition between biological communities
  • Geographical identity, the Alaskan areas of Kenai and Denali as at the edge of the Arctic
  • Portend of climate change and with it a transforming phenology (alteration of life cycle events)

Through the residency, I was able to:
  • Explore spatial audio field recording techniques by focusing on the use of ambisonic microphones.
  • Develop and test strategies for distributed spatial audio recording using several GPS-tracked, time-synchronized recorders.
  • Create an extensive library of sound recordings for use in new compositions, performances, and installations for multichannel sound systems and high-density loudspeaker arrays; the total amount of audio captured on this trip was approximately 120 hours.

Kenai and Denali proved to be excellent sites because:
  • As places new to me, they required a high level of attention.
  • I could experience an expanded acoustic horizon; without competition from human-caused noise, one can hear further, and recordings have a related expansive quality.
  • It is easy to find quietness; different figure / ground relationships become noticeable, and new minimum technical requirements for equipment are evident.
  • There is a great diversity in the built environment, land-use, and natural land areas accessible from Alaskan highways.
  • There is extended daylight, which provides more time for exploration / experimentation.

Outwash (2019)

Outwash was composed in 2019 for high density loudspeaker arrays (HDLA) with high order ambisonics. Development of the piece began during a residency at Virginia Tech’s Cube in March 2019 and it was later completed at RISD’s Studio for Research in Sound and Technology (SRST). In this work, twenty independent voices reliant upon the same underlying erratic synthesis procedure move throughout the room in varied spatial formations. Audible contours and modulations are produced by parametric deviation and distance fluctuations between the voices of this ensemble. While the piece is set in its duration and sequence, real-time processes afford unique outcomes in each performance. The piece was created in MaxMSP and runs autonomously. Outwash premiered at the Cube Fest with a 140 channel loudspeaker array (2019 Virginia Tech, Blacksburg) and was also included in the International Computer Music Conference (2021 Santiago).

Outwash was most recently presented in fifth order ambisonics for a 41.4 channel loudspeaker array on June 9, 2023 in concert at the Lindemann Performing Arts Center, Brown University.  
︎︎︎ Composition documentation, Virginia Tech 2019 

Quarries (2016-curr.)

︎︎︎ October 23, 2022. Machines with Magnets, Pawtucket, RI
Quarries is a flexible, evolving system for electroacoustic improvisation building upon aspects of my prior systems with refined approaches to synthesis, sampling, and audio processing. Quarries has evolved over a period of seven years, developed between performances at club venues, taking into account the discoveries made along the way. The underlying programming language has shifted from Pure Data (Pd) to MaxMSP.

At first focused on the processing of contact mic’ed percussion instruments, the software has expanded to include its own internal synthesis engine with I/O for external effects and modular synths. For gestural control, the performer presently uses three Sensel Morph multitouch sensors and a DJ-style MIDI controller (Faderfox DJ-44), among other equipment to augment the system.

︎︎︎ January 15, 2021. Non-Event at Home
Both through chance and intention, the performer adjusts parameters of an erratic synthesis process. Responding to the results, the player samples segments for further manipulation, hunts for emergent patterns, provides contrast with sampled live percussion, and improvises within the arising circumstances.

Quarries was first presented at the Pure Data Convention (PdCon) in 2016 (NYU / Stevens Institute of Technology). Following performances included several venues in Rhode Island, Anchorage Museum (2017 Alaska), Human Resources (2019 Los Angeles), and a livestream for Boston’s Non-Event Experimental and New Music Series in January 2021.
︎︎︎ March 30, 2018. Machines wiht Magnets, Pawtucket, RI

︎︎︎ May 6, 2017. AS220, Providence, RI

︎︎︎ July 22, 2016. Machines with Magnets, Pawtucket, RI

︎︎︎ Quarries in performance 

Quarries HSL (2016-18)

Quarries HSL is an improvisational performance approaching high density loudspeaker arrays as new interfaces for musical expression. Central to the piece is the use of visual image data scanned from works on paper using a live camera, applied as spatial audio positions and movements. For example, color data is applied as ambisonic coordinates with hue = azimuth, saturation = distance, and lightness = elevation. The works on paper from which the scans are taken function as a catalog of possibilities to be explored during performance. The performer refines the sonic experience through image processing, including adjustments to scan rate, zoom, hue shift, brightness, contrast, and saturation. Using multitouch sensors and a MIDI controller, the performer also creates the sounds spatialized by the camera scanning process. These interfaces provide access to parameters for sound synthesis and transformations of field recordings.

The piece builds upon my previous investigations in graphic sound synthesis, and was developed between 2015-2017 at Virginia Tech’s Cube, University of Birmingham’s BEAST, and RPI’s EMPAC. It has been configured for as many as 140 channels. As the title suggests, this work is a variation on my Quarries system detailed above.

This workwas performed at the International Conference on New Interfaces for Musical Expression (2018 Virginia Tech, Blacksburg) and the International Computer Music Conference (2018, Daegu). It was also performed at the BEAST FEaST (2017, Birmingham UK) and Cube Fest (2016 Virginia Tech, Blacksburg).

︎︎︎ Quarries HSL demonstration

︎︎︎ Quarries HSL sound check at VT Cube