Skip to content

The Gravity Harps: Process and Credits


The Gravity Harps were my first large-scale project and were accordingly, the most difficult.  Just summarizing all of the work, ideas and people is a bit overwhelming.  This page is intended to be the canonical document about the two dozen people and the innumerable processes involved from 2009 to 2015.

I’m grateful to everyone for their participation and fortitude.  At the end of this document is a summary of everyone’s names, their roles, and links to their websites.

Demos and Commission

Cambridge, MA

Fall 2009

In the Fall of 2009, Björk, Michel Gondry, James Merry, and a small contingent visited the MIT Media Lab, asking to see demos of grad students’ musical projects.  A lot of demos for important people happen at the Lab.  But this was extra special.  A long line of us gathered outside a conference room holding our laptops or inventions, waiting for our 20 minutes with Björk and Gondry.  At the end of the day, three of us were surprised to be invited to participate in further talks about a new project.  We were Noah Feehan, Mark Feldmeier, and myself.  

The project was to be a 3D IMAX film called Biophilia about the intersection of music, technology, and nature.  And we were being invited to help develop new musical instruments for it.

Mark was the only one with experience developing large projects and helped guide us on the subjects of scope, budget, and schedule.  And then Mark transitioned out to return to his Plan A – a company designing electronic music technologies.

Early Design Process

Boston, MA

Spring 2010

Noah and I got started developing ideas for Biophilia.  Noah’s ideas were more visual and cinematic and mine were more strictly musical.  I got so much help on the prototypes from Mihaeko and her fine skills and good sense.  The list below shows my designs and prototypes in this phase.

Design: Walkers, Weavers, and Mechanical Music

These designs explore ways to extend the concept of a music box into something more alive and more cinematic.

First I played around by making music box reels. This reel plays one of the many concurrent musical parts from Moon.

Then I imagined replacing the reel with a woven tapestry of music. There would be two pairs of machines, a weaver and a human-sized music box full of tuned percussion instruments. They are connected by tapestry which carries music encoded in its knots from one machine to the other. Gravity makes the tension between them visceral.


Another design has the two machines pulling against each other, while slowly walking in one direction.

Weaver and Music Box

I love this design and may still try to use it in a future project. 

Prototype: Water Harp

Björk had asked us to explore instruments that harness forces of nature.  I chose to start with water, or gravity and surface tension, to be more precise.

The idea was to use water’s insistent softness to create music. In this rough prototype, I dropped water droplets on the strings of a harp to set them resonating.

Trying to aim the droplets precisely was maddening.  They left the nozzles in non-deterministic directions and drifted in the slightest breeze. I modified the nozzles with guide-needles and increased the water’s surface tension by adding salt or sugar.  But some of the randomness remained.

I liked the result when I finally got it working.  And I had a lot of 11th-hour help from the precise and perceptive Mihaeko.

This works nicely on film! But it would be hard to recreate on a tour. So these videos are all that is left of the work.

Photos by Mihaeko.

Design: Generative Music with EEG and Genetic Algorithms

This design creates a collaboration between an AI and Björk’s subconscious mind. And it does it in a way that isn’t BS, like many other brain-music projects.


A computer is running an evolutionary algorithm that evolves a population of sensitive musical sounds and patterns. Björk listens on headphones with her eyes closed, feeling the music. Measurements from biometric sensors (most likely brain) are used to infer her levels of pleasure and displeasure. This pleasure measurement is used as the selection determinant for the genetic algorithm. With some learning and fine tuning, this should create a reinforcing feedback loop that generates ever more pleasing music for Björk.


This is a machine that requires a human subconscious as a functional element. It also creates an intimate machine interaction that requires no volition on the part of the human.


The music evolved in collaboration with each individual human brain may eventually settle around patterns that are unique to that person and reveal aspects of their deeper nature.

Illustrations by Josh Wall.

Design: Timbrebox

Björk asked me to explore the possibility of a keyboard instrument that sounded like a gamelan. My favorite aspects of gamelan music are the range of timbres and the shimmer created by the interference of the male and female instruments.

I explored this idea using raw JavaScript and gamelan samples recorded by Akito van Troyer.


Click the image above to open the app and explore the sounds. The white bottom of each key is a damper to stop the resonating of each virtual metal bar. It takes a moment to load fully because of the high-quality sound samples.

I also tried an experiment with the Heliphon, a computer-controlled metallophone by my friends in Ensemble Robot.

Design: Universal Keyboard for Atypical Musical Systems

I was already imagining how these new sounds might be organized and played live.  Below is a design detail from a proposed universal keyboard for diverse tunings, timbres, patterns, and processes. The physical layout is based on a Bosanquet Generalized Keyboard. Each key’s colors and image can be assigned by software, allowing for many interactive arrangements.



Prototype: Ripple Table Experiments

Continuing to explore water and waves, I created a ripple table with glass and lights, a mirror and a scrim of oiled paper. One concept was to trigger digital sounds using optical sensors which respond to the ripple patterns.  Here is the first prototype.

This whole idea is inspired by the Sound Forms project by my good friend Seth Hunter.

This prototypes worked well but needed to operate in a vibration-free environment.  Si I kept designing.

After months of contributing his own, more cinematic ideas, Noah left for a previous commitment.   I continued on with help from Mihaeko.

Pendulum Design Process

Boston, MA

Summer/Fall 2010

Prototype: Pendulum Instruments

Björk was inspired by Foucault pendulums because they are awesome.  Playing a song with a single pendulum presented design issues that I couldn’t resolve.  In particular, the pendulum runs completely out of kinetic energy by the top of its swing.  So I started woking with multiple pendulums that could mechanically play music towards the bottoms of their swings.

The first prototype, called The Marinas, were made with objects and materials I found around my loft.   They showed how three pendulums with equal periods and different phases can make many musical patterns.  Mihaeko created the little string instruments and lent the projects the tuning pins from her cello.

The second version includes one more voice and a change in timbre.


The next challenge was playing a specific piece of music.  Björk asked me to focus on playing the new song Solstice. Her assistant James Merry sent me this hand transcription of the interesting new piece, which has both a floating lightness and a tension that can never settle back down to Earth.  And its time signature shifts between 6/4, 7/4, and 12/4.



Design: Finding the Best Layout

The first designs arranged the pendulums in a simple, straight line.  Cinematically, this makes some very dramatic perspectives possible.  But I also experimented with other layouts.

The Biophilia Project was ever-evolving at this point.  And the current plan was to shoot one segment in an abandoned power station outside Reykjavik.  The space had 21m ( 70 ft.) ceilings what could allow for long, slow pendulums.  And Björk could walk in and out of the swinging patterns while singing.

An amazing thing happens when the circular layout is set in motion.  I could see it in my pencil sketches.  And I asked illustrator Fardad Faridi to create a simple animation showing the hypnotic, moving pattern.  It echoes the theme of natural celestial cycles

The gold cube at the bottom represents the approximate scale of a human being, walking among the enormous, swinging pendulums.

Production pt.  1: Bootstrapping 

Brooklyn, NY

Winter 2011

Björk loved this new design as much as I did.  So we were off to the races.

I’d never built anything on this scale before.  I was thrilled, terrified, full of ideas, totally without a map, and hopeful that by the end I’d have some idea of what I was doing.

Björk wanted the whole piece to be built in New York, where she and I could collaborate more closely.  So Mihaeko and I started the search for a new home and a new studio in Brooklyn.

We also received the news that Biophilia would now be many more things, including a tour!  This was very exciting but also very challenging.  A piece built for a tour must break apart modularly, be certified safe in public spaces, have custom cases for all of its parts, and last for years of assembly, disassembly, shipping, and performance.

So I needed to hire some experienced people.   People like Dan Paluska and Bill Washabaugh.

Bill and Dan explored possible drive mechanisms for what was coming to be known as the Pendulum Ring.  Bill and Dan called the prototype …

Cavatortic Pendulation

This prototype tests a single-motor drive mechanism with sinusoidal cams and inverted pendulums to control each pendulums’ natural period.

Mathematically, the prototype produces perfect simple harmonic motion.  But we learned that we cannot fool the eye when it comes to pendulums.   They will have to swing freely to be believable.  This is why we prototype — to discover what it true in practice but not in theory.


The new stage and lighting designs were starting to emerge.  The performance would be in the round, with Björk and performers in the center and the pendulums undulating around them or lifted out of the way.

Bill and Dan created a beautiful CAD model of the whole system.

Space Search

I was originally planning to work in Matthew Barney’s studio, as he was away filming River of Fundament.  But that window closed as our start date dragged on, anchored by an intercity move and a thousand other details.  And so started the search for an affordable, two-story-tall workshop.  In New York, no less.

It took weeks of snow-soaked footwork, some sleuthing, and some threatened legal action against an unscrupulous agent, but I eventually landed us a huge space right in Brooklyn that was perfect.


Production pt. 2: Pendulum Ring

Brooklyn, NY

Spring 2011

Production Crew

This was my first large-scale production phase.   I looked for extremely adventurous generalists with depth in mechanical engineering and CAD, fabrication, electrical engineering, and pretty much anything that might be useful.

I found “recovering physicist” Doug Ruuska and mechanical engineer Karl Biewald to build pretty much everything mechanical and physical;  fellow Media Lab alum James Patten to make the motor controllers; fine artist Mikaeko on design details and fine fabrication;  myself on whole-system design, software, and having just a couple fingers in every part of the project.

Doug literally lived at the workshop, sleeping on the high scaffold in the freezing winter and the sofa in the sweltering summer.  Karl came with his own entire CNC machine shop nearby.  James juggled a number of other projects in his own studio and magically appeared occasionally with tools or test equipment or circuit boards.  Mikaeko worked on so many iterations of harps, solving all of their structural, musical, and aesthetic issues.  And I plowed away for 70-90 hours a week on software, designs, communication and documentation, getting caught up in all other details, and trying to hang on.

This was my first big project.  If there is a project management mistake I didn’t make, it’s only because I ran out of time.

Pendulum Choreographer

I created a lot of videos, images, and simulations to communicate ideas to Björk and others.

Below is a screen shot of the Pendulum Choreographer, for use with an iteration of the design that dropped the pendulum arms one at a time.   Click it to play with the interactive tool.  You can use the pill-shaped buttons to change the physical patterns by rearranging the location of each pendulum arm.

Pendulum Choreography


Evolution of the Harps

Mikaeko’s many iterations of harps became ever-more-beautiful-looking and -sounding.   There aren’t enough photos.  But here is an incomplete fossil record of the process, ending with hand-formed fiberglass and a spruce/aluminum composite structure.


Harp Wing Design

We built a ventilated isolation room so Mihaeko could cast fiberglass forms.  The results were becoming very graceful.

2011-04-05 15.27.28


Motor Controllers

James finished a sharp-looking circuit board that can control two motors, read two rotary encoders, speak on an RS485 network, and was re/programmable — a feature that came in very handy later.


The Beastly Truss System

On the mechanical side, the biggest single beast was the 13m wide truss system and its dynamic loads, modular sections,  assembly process, and its hundreds of power and data cables.

Doug launched a massive networking campaign to secure enough local fabricators to build all of the sections simultaneously. I believe this process involved a lot of Doug’s secret weapons: quality beverages, charm, and yarn-spinning.


Karl created some beautiful renderings of the whole structure.

Layered System Photo.Final Color Output_crop2

Layered System Photo.Final Color Output_crop


Design Progress and Bad Dreams

But something troubling was happening.  The graceful, organic form was becoming menacing as it grew to leviathan proportions — aesthetically and practically.  Björk and I were both having bad dreams about it.   The more real it became, the clearer the difficulties and expenses of touring it became.  So Björk and I met to discuss a smaller version.

Production pt. 3: Gravity Harps

Brooklyn, NY

Spring 2011

In one of the previous versions of the Pendulum Ring, each harp could rotate to play any note.  I made a quick sketch of a modest version of that idea.  This would have four pendulums closer to a human scale.

Gravity Flower, Prototype 1

It was heartbreaking to change direction when we were so heavily invested in the Pendulum Ring.  Especially when we were all exhausted already.  And with only five weeks left before my final deadline with Björk.

But the upside was that we had so much already figured out and so many tools and materials in place.   Mikaeko and I understood harps very well by now.  James’s circuit board could be reprogrammed to control the two motors of the new design.  And many of the Pendulum Ring’s mechanical designs could be applied to the new instrument.

Here is a boring physics test we created to verify that the rotation of the harp did not affect the swinging motion of the pendulum.

The New Harps

I designed a new, circular harp for the new instrument.  Mihaeko worked out the details and made it beautiful and functional.  Her new designs (one sketch below) had to account for many factors and processes.


Here is one iteration with fiberglass, poplar, and aluminum.


The final version used a composite material developed by Mihaeko, made of sculpted layers of walnut veneer and epoxy.  It was beautiful, sounded great, and was nearly as indestructible as fiberglass.

Barrel Harp

The tuning heads look like they were made with a 5-axis CNC process.  But they were hand-shaped by Mihaeko out of walnut.

harp prototype 3

Motions and Mechanisms

And James’s updated firmware for the motor controller was coming along well.  This free-swinging version presented and unusual challenge.  We needed the pendulums to swing freely but receive little kicks to keep them swinging high and occasionally nudged into sync.

Here is an early video I composited to demonstrate for Björk how the four-phase motions together play the piece.  It uses samples we recorded from Mihaeko’s current harp at the time.

Karl and Doug still had a massive amount of engineering and fabrication ahead of them.



parts in production









The Countdown to the Deadline

And finally, James’s four motor controllers were finished.  And he wrote a Python test script that could get the pendulums started, wait several minutes to give each time get into sync, and could rotate each harp to a precise position at the right time to play the sequence for Solstice.  It was wonderful to see everything moving.


Karl, Doug, and I finished making structures and big clamps to hang the pendulums off of the workshop’s columns.    And Doug began running power and data cables along the high ceiling.

I vote Doug for #1 tool-wielding ladder monkey.


Here’s a quick video of the first test of the whole system: harps, motors and mechanicals, structural parts, motor controllers.

Production pt. 4 : Tour Prep, Software

Brooklyn, NY

Summer 2011

Now the basic prototype worked.  But we needed much more before we could tour with it.

The Sprawling Software Begins

I started work on what would become a sprawling software system including graphical interfaces for calibration, for troubleshooting, for composition, and for live performance.  The core of the software measured the synchrony and stability of the pendulum rhythms, could record and recall the precise positions of each string on each harp, and managed the loading and play|pause|rewind of musical compositions.

The first new interface to get written was the troubleshooting interface.  We had timing errors that were impossible to understand just by looking at the rhythms.  The interface reads a number of values from the motor controllers and graphs them to help make visible patterns.

amplitude bug seen in spin-down

The Touring Kit

I had amazing help in the 11th hour from friends and fellow MIT alums Ryan Wistort, David Cranor and Seth Hunter.

Seth, a friend of his, and I disassembled the whole system all through one sweltering night of sweat-slippery ladders and tools.

We needed to build all creates for all of the parts – which was refreshingly straightforward but still takes days.


And we needed a way to pre-stretch harp strings to get them to ‘settle’, so they could stay in tune for hours without tuning.  We did this with a simple case called The Rack, which simulated the approximate correct string lengths.  And we would tune the rack every time we tuned the harps, to keep them all in sync.


The surprise was that the rack sounded great.  So we experimented with amplifying and playing it.   The contact mic was also useful for tuning.


And we began to prepare for the upcoming tour as if for a long and dangerous sea journey.  We packed every tool, part, and material that we feared we might ever need to maintain, repair, or rebuild the system.  I thought a lot about Ernest Shackleton’s carpenter.

And I started to train Ryan, who would be handling the second part of Björk’s month-long residency in Manchester, UK.


First Performances, First Shows

Manchester, UK

Fall 2011

Ryan and I arrived in Manchester exhausted and sick.  And completely unprepared and unaware that there would be no rest for a few weeks.  Our ‘venue’ was a beautiful old Victorian market building that had been used for storage until recently.  An army of riggers climbed ropes to the high ceiling all day installing trusswork, lighting, speakers, and enough heavy cables to stretch to Paris.

New Stands, Unexpectedly

The first thing we discovered was that our plans to mount the pendulums off of the building’s antique columns had been nixed and we needed to come up with a new plan ASAP.  We tried mounting with the aluminum trusswork but it flexed and twisted under the heavy pendulums.

Ryan and I made some sketches of new indestructible stands with gargantuan strength.  There was no time to be wrong a third time.   But we really were still just guessing about the forces involved.  The Gravity Harps were brand new and still completely mysterious creatures to us.

Ryan got to work with a local fabricator, welding steel and hewing railroad lumber.  I bought out all of the threaded rod and nyloc nuts in one hardware store and bought the biggest gangster gat of a drill I’ve ever seen.  Like something your grandfather would use to kill grizzly bears or repair buffalo.

And of course, I couldn’t find lumber or a hardware store in London because they are called timber and engineer’s supply there.  So we needed a local guide to interpret for us.  We met Charlotte Utting-Brown at random while asking for directions and found she knows Manchester extensively, has perfect pitch, and loves Björk’s music.  SOLD.  


Our British Interpreter

I’d also guessed that we needed a dedicated tuner to tune the 44 harp strings before each show, over and over, until the tuning settled.  I was still learning how hard it would be to tune them in a cold venue, fill it with thousands of warm/humid people, add hot lights, and have the harps still be in tune at the end of the show four hours later.

The tuning was such an intensive process there would be little time for just one person to search for and resolve any other issues before the show.

Charlotte also helped us immensely with her knowledge of where to find the right parts and people for our continuing scramble.  I love Google but the best interface to a new city is still a resourceful local.

Mysterious Creature / The Quest for Certainty

With a week before the first show, Ryan and I were still wrestling with the Gravity Harps, which were strangely different and unpredictable after being reassembled.  And we needed the system to be 100% perfectly reliable during the performances.

I began writing the command-line show control interface that we still use today because I was getting nervous about the stability of my homemade, pre-official prototype of WebSockets used in the graphical interfaces.   

Here are Ryan and Charlotte tensely observing the current and unknowable state of the Gravity Harps.  By now, they would behave when we were looking directly at them.  But we still didn’t trust them.  We still changed parts and made impulsive adjustments, more as voodoo than science.

The Sound and the Fury

All of this high-tension troubleshooting was happening during the hours of loud booms and flashing lights of sound checks and lighting checks and rehearsals.  Ryan and I were definitely unraveling as the show came beautifully together.   We were twitching and staring vacantly and mistakenly locking ourselves out of our shared apartment.

Debut in Manchester, UK

The First Performance

The very first performance of Björk’s epic, new Biophilia project closed with a very intimate and exposed duet between her and the Gravity Harps.  I thought I would have a heart attack waiting for something to go wrong during the 6-minute song.  And afterward, I couldn’t stop pacing around in the chilly, dark night behind the venue, letting the adrenaline subside.

I didn’t know it then, but this was a ritual I’d be acting out dozens of times over the next 12 months.

I’d like to offer special thanks to Ryan for bravely operating the Gravity Harps for the last two weeks of performances in Manchester.  He felt the same pressure for perfection that I did.

And the show was a great success, of course.  A testament to the good ideas and hard work of so many people involved.  And mostly to Björk herself, of course.

Bjork photographed in Manchester on 23 June 2011. Photo by: Carsten Windhorst / /

Bjork photographed in Manchester on 23 June 2011. Photo by: Carsten Windhorst / /




The very first show was billed as a preview because everything was still in flux.  The only video of that show that I can find online shows Björk improvising and exploring the vocal part live as only she can.

The Reykjavik Residency

Reykjavik, Iceland

Fall 2011

The next stop on the tour was a month in Reykjavik!

My local guide to Iceland would be Frank Arthur Blöndahl Cassata, who I met because he was the most helpful person on the Iceland subreddit.  I was also joined by Astrophysics PhD candidate Adrienne Hillary Sanctuary, who introduced herself out of the blue online and had a little bit of funding to come and learn about music and new possibilities.

I was grateful not only for their help but for the opportunity to train more people able to take over on the tour.  The months away were causing a lot of trouble in my both my professional and personal life.

A Complete Re-Write

I used the downtime between shows to refactor all of the software into a more intentional structure, to fix bugs, and to add features.

The big new feature was the generation of MIDI time code based on the timing of the pendulums.   We were hoping to use that to synchronize the lights and show control system to the swinging of the pendulum – since it was impossible to sync the pendulums to anything.

Training and Rituals

I was also teaching Frank and Hillary the ways of the Gravity Harps.  These ranged from the abstract and mathematical to the musical to the very physical.

Here is Frank with The Big Wrench, fine-tuning the natural timing of the pendulums by moving the counterweights up and down by sometimes less than a millimeter.  This photo is from another venue but demonstrates the process well.


Below is a video of Frank carefully comparing the natural timings of the pendulums.

The motor controllers have a very limited ability to affect the timing of the pendulums.  So their natural periods need to be as close to identical as we can physically get them.  When they all naturally swing in the same rhythm at least 20 times with no visible difference, we call them equal.  This iterative process of fine-tuning can take hours and must be done every time the Gravity Harps are moved.

And [Near-] Arctic Adventures

The most memorable event may have been getting trapped on the roof of the opera house when Frank forgot that a door automatically locks.  The sky was alive with the Aurora Borealis and we held onto the flat roof in howling Icelandic winds that are known to lift grown people.  If it wasn’t for cell phones, our bones would probably still be up there.  Many thanks to our rescuers.  Photo by Hillary Sanctuary.


I never know what to do when someone points a camera at me.


Also – when in Iceland …

… make an appropriate bike.  I covered this rental with reindeer fur.  When I returned it, the owner decided to keep it this way.



Grotta Lighthouse

Reykjavik, Iceland

Winter 2011

The Grotta Lighthouse is believed by many to be haunted.  It’s only accessible at low tide, and then only barely.  When the month of shows was finished, Björk took all the invented instruments to the island to experiment with new songs.


Frank joined her as an audio engineer and newly-minted pendulumologist.  Frank did an amazing job moving the Gravity Harps across the muddy isthmus and also rebuilding the whole system himself for the first time.

Frank and I worked out some ways to connect the Gravity Harps to the songs created in the Biophilia iPad app suite.  But Björk wanted a more intuitive way to compose for them.  So I created a new interface for composition and improvisation.

You can play with it here.  Below are the details I sent to Björk and Frank.

It’s inspired by recombinant DNA.  You can make music codons – little phrases – and arrange them in any sequence to compose more complex structures.  And you can modify and re-order them while the composition is playing.

Anything composed and saved using this interface can be played on the Gravity Harps.





Frank used it to score a particularly spooky Icelandic song for his solo overnight stay on the haunted island, isolated by the high tide.


New York Residency

New York Hall of Science & Roseland

Winter 2012

Mihaeko joined me during the New York Residency.  And I finally started to feel like I understood and trusted the Gravity Harps.  The refactored control software was solid.  The harps held their tuning for days in the dry winter air.  I was using the lull of crises to work on larger issues like new cables, new road cases, and strange large-scale drifting patterns in the pendulum sync.

The new road cases are about 13 ft (4m) long.  You can just imagine how heavy they are empty.   Mihaeko and I sourced the lumber and built them in one bright and cold winter afternoon outdoors behind the venue.  When the cases were filled, we would walk them like coffins with four strong people lifting.


The first shows were held in a retro-futuristic space at the New York Hall of Science.  I invited folks from the production crew to join us for the setup process, for that full-circle satisfaction of seeing all that work come to life.

Here I am showing the new show control software to Doug, Karl, and James.

The blue glass walls of the space worked perfectly for the aesthetic of the Biophilia show.


I never shot a video of any performance, out of respect for Björk’s no cameras request.  All I have to remember these shows by is other peoples’ phone videos.  Here is one from the New York Hall of Science shows.

The shows at the New York Hall of Science happened in a sort of intimate and reverent hush.  When we packed up and moved to Roseland, the shows took on loud, wild party feeling.  It would be hard to pick a favorite.  


Buenos Aires Residency

Buenos Aires, Argentina

Spring 2012

Mihaeko and I flew to Buenos Aires for the next Biophilia Residency, where we were plagued by constant minor problems.  Computers and other equipment would spontaneously die.  And we’d go scrambling in an unfamiliar city looking to replace parts from another hemisphere.

In the constantly-shifting famously-high humidity of Buenos Aires, the harps would be out of tune within a half hour — which was catastrophically unacceptable.  We spent days inventing and testing methods to stabilize them – changing string weights, taking data to try to predict the direction and degree of drift depending upon the current relative humidity. There was no magic bullet.  But a combination of techniques got us close enough.

You’ve seen enough Solstice by now.  So here is Björk and Manu Delago performing One Day as an encore in Buenos Aires.


The residency ended a week early.  Björk had been working hard against the vocal cord nodules that can affect anyone who sings this hard for years.  But she felt herself slipping and would not compromise on the quality of her performances.   After the dangerous surgery and a few months of rehab, she came back sounding better than ever.

Modification and Training

London, UK

Summer 2012

In summer of 2012, Frank and I flew to London to modify the Gravity Harps and to practice the setup, maintenance, operation, and breakdown procedures.  We both had the flu.  There was only one bed in our hotel and I slept on a pile of sofa cushions.

We were also adding slip rings to the gravity harps to carry the microphone signals so we wouldn’t need to use radio transmitters anymore.  I made a sketch of the plan because I think better in drawings.


Frank and I both had to remind each other of protocols and refer to our own previous documentation of the processes.  But by the end, Frank knew more than anyone in the world about the Gravity Harps except me.

Remainder of Biophilia Tour

All Over the World


Frank Cassata

Just this guy.  Frank finished out the rest of the tour and did it wonderfully.  He was a better fit than me because he had many other skills applicable to the tour and because it fit into his life much better than mine.   He also got along with the tour manager.  I should use a less skeptical-looking photo for this part, but I’m in a hurry so this is what we get.  😉

Commission from MU Gallery

Eindhoven, Netherlands

Spring 2013

The nice folks at MU Gallery in Eindhoven invited me to participate in an upcoming show called Sounds Like Art.  They were hoping I could bring the Gravity Harps.  That would have been far too complicated, with shipping containers and international carnet documents disrupted.  So, with Björk’s gracious permission, I created a second iteration of the Gravity Harps.

The new Gravity Harps would be very similar to the original version.  Except they would have harps with a wider musical range and an all-new control system.  And there was a brand-new mechanical-linkage plucker mechanism.

Karl still had all of the CAD files and was able to produce the structures.  I was assisted mostly by new friend Di Mainstone, herself an amazing artist working with sound, bridges, dance, and much more.  And we had some invaluable help from studio-mate Andrea Lauer, designer of costumes, sets, and wearable technologies.

Another Ridiculous Deadline

And they had to be built from scratch in two weeks.  I told MU Gallery from the beginning that the whole project would be down to the wire.  Promise: delivered.

Di and I worked around the clock at my workshop and Brooklyn.  And the sleeplessness continued in Eindhoven, where we had great help from gallery production guy extraordinaire Kor Smeenge.

Here we are stringing and tuning the harps after finishing the last of the finer carpentry.



Those Pluckers

The new plucker mechanisms looked great and worked perfectly.


Gravity Harps v2 at Mu Gallery


The New Control System

The new control system addresses the wish-list I’d slowly developed while touring with the original Gravity Harps.  Variable periods and timing.  Variable note dynamics.

I was still learning that I can never write software while directing other people’s work. Too much distraction and too little continuity.  So I didn’t even get to start on the new system until 20 hours before the opening.  Typical.

I stayed overnight in the glassy, open gallery while a snowstorm swirled around it like a snow globe.  I spent four hours just stabilizing the serial communication with the commercial motor controllers, sort of wondering how I’d ended up at this point in my life.

By dawn I had them all synchronizing and playing.  And I spent the rest of the day adding features, motions, and sounds for the upcoming opening that evening.  I never did make it home for a shower before the opening, my talk, the Q&A, chatting with the visitors, the afterparty.  The rest of the evening is replaced by that special blur only sleep deprivation can cause.

But I’d had my first official gallery show.

MoMA Björk Retrospective

New York, NY

Winter/Spring/Summer 2015

In winter 2015 I received word that the Gravity Harps would be featured in a new MoMA retrospective about Björk.  I began a set of meetings to help MoMA staff plan for the requirements and best options.  I found myself also advising them about other Biophilia-related artifacts, in part because Björk’s team were focused on quickly finishing the Vulnicura record after someone maliciously leaked an early version online.

The first phase of the real work took place in a large staging room in the basement of MoMA.  My task was to restore the Gravity Harps to museum-quality readiness after they’d been moved around the world and dis/assembled dozens of times.  It was humbling to see them amid dozens of priceless artworks processed in the same room.

I was assisted by Ayodamola Okunseinde as I rebuilt the Gravity Harps, cleaned them up, tested them, and updated their software to operate in cycles all day, every day.

After much discussion about how to present them, I was overjoyed to discover they would be displayed in one of my favorite locations in any museum — the Gund Lobby at the entrance of MoMA.  And I felt honored to have my name on the wall.  Especially since I’m a terrible self-promoter who has never applied for a single show or grant or residency.

A few weeks after the opening, a technical problem caused them to be shut down on a day when I could not come in to troubleshoot them.  Luckily I have a friend who specializes in saving the day.  Andrea Lauer stepped up to visit MoMA and use her keen perception to correctly diagnose the source of the trouble.  And she used a tiny bit of her extensive knowledge of materials to repair it.  After that, everything was working perfectly and smoothly.  Though I still did check in on them twice a week just to be sure.


photo by Klaus Biesenbach

photo by Klaus Biesenbach





Summary Credits for Gravity Harps, in order of mention:


Source of entire Biophilia Project, in all of its many manifestations

Michel Gondry

Film treatment and other concepts

James Merry

Tireless organization and communication on behalf of Björk and Biophilia

Mark Feldmeier

Early advice on scope, budget, and schedule.

Noah Feehan

Many early design concepts and prototypes

Andy Cavatorta

Recipient of commission.  Design collaborator with Björk.  Inventor, designer, whole-system engineer, and software engineer for both versions of Gravity Harps.  Production manager.  Touring technician and operator on the first year of the tour.  Restorer and operator for MoMA exhibition.


Extensive assistance in design and prototyping, fine sculpture and fabrication, tuning and tour support.

Akito Van Troyer

Source of gamelan samples used in Timbrebox design demo.

Seth Hunter

Help with the first, arduous disassembly and crating.  Inspiration for ripple tanks prototype.

Fardad Faridi

3D animations of original Pendulum Ring

Dan Paluska

CAD model and early drive prototype for Pendulum Ring

Bill Washabaugh

CAD model and early drive prototype for Pendulum Ring

Doug Ruuska

Extensive mechanical engineering and fabrication during production phase.

Karl Biewald

Extensive mechanical engineering and fabrication during production phase.  Engineering and metal fabrication for second version of Gravity Harps.

James Patten

Motor controller circuit boards and the first Python test script to operate them.

Ryan Wistort

Help with crates, The Rack, the tour kit, building the stands, troubleshooting the system, and operating it during the 2nd half of the Manchester residency.

David Cranor

Help with crates, The Rack, and the tour kit.

Charlotte Utting-Brown

Help with tuning, guide to Manchester

Frank Arthur Blöndahl Cassata

Everything related to touring and operating the Gravity Harps.  The world’s only other certified pendulologist.   Remote technical tester of composition software.

Adrienne Hillary Sanctuary

Assistance with tuning and troubleshooting harps during Reykjavik residency.

Di Mainstone

Fabrication and extensive practical support during the creation of the second version of the Gravity Harps.

Andrea Lauer

Support and problem solving during the creation of the second version of the Gravity Harps and during the MoMA Retrospective.

Kor Smeenge

Support and fabrication during the creation of the second version of the Gravity Harps.

Ayodamola Okunseinde

Support during the preparations for MoMA Retrospective.