Monday, February 10, 2020

The BitKlavier: A Performer's Perspective

This post takes the format of a formal-ish paper about my experience of developing a practice on the BitKlavier. It goes quite in-depth, and I hope it can be helpful to anybody who wants to engage with this fascinating instrument for performance, teaching, and pleasure. I may add to it over time as I get feedback from people who use the instrument.

- Adam Sliwinski
Feb 10, 2020

Table of Contents 

  • Introduction
  • The Synchronic setting (w/ performance video)
  • The Nostalgic Setting (w/ performance video)
  • Tuning
  • Software Alteration and Interpretation 
  • Reworking Traditional Repertoire
  • Pedagogy



In 2013, I started planning a new solo piece with Dan Trueman. We previously collaborated on Five (and a half) Gardens and neither Anvil nor pulley for Sō Percussion, and he had already written solo pieces for Jason Treuting and Josh Quillen. I steered the conversation towards percussion keyboard instruments such as marimba and vibraphone.

While discussing our project, Trueman introduced me to a new concept he was working on. It was a "prepared digital piano," which grew out of neither Anvil nor Pulley. The instrument was thrilling: metronomes emerged out of the keyboard, long notes washed backwards in waves beyond their release, and any kind of tuning was possible.

I jumped in, asking if I could try the software and practice his first few pieces. As I learned them and my enthusiasm grew, Trueman starting writing more pieces for me. Our mutual excitement yielded the Nostalgic Synchronic set of eight etudes for what he soon called the "BitKlavier." I recorded the entire set for New Amsterdam Records in 2015, which also included a New York Times-reviewed release concert in New York City.

This article is a concise but detailed exploration of the main settings in the early versions of the BitKlavier, and how I adjusted my practice to grapple with them. My keyboard skills, which were not yet adequate for all of the challenges these pieces contained, grew enormously under the supervision of my wife Cristina Altamura.

The BitKlavier and the Nostalgic Synchronic Etudes 

Many of the following score examples resemble traditional piano music. The grand staff, pedal markings, and the notes themselves will be familiar to any pianist. Hidden inside each of them is a new expressive tool, which changes the nature of the keyboard instrument in ways which are impossible with physical instruments: the BitKlavier embodies a vast array of potential behaviors which reside in algorithms rather that mechanisms.

The settings in the BitKlavier fundamentally alter the performer’s mind/body relationship with the keyboard: The synchronic setting introduces metronomes which can be re-triggered, the nostalgic setting introduces the possibility of growth in note intensity where only decay previously existed, and the tuning settings allow for instantaneous tuning changes in the middle of a piece.

The Synchronic Setting 

Releasing a held octave in the opening bars of the first Nostalgic Synchronic etude launches a metronome. The timing of further attacks depends on the consequence of these releases. This is a new concept and physical reality for keyboard playing. In traditional repertoire, key releases on the piano or organ matter in voicing, timing, and duration, but they rarely trigger new musical events which require their own response.

In etude number 1 entitled “Prelude” (example 1), the cue notes in the score indicate what will happen upon release: sixteenth notes built from the octave will play at 100 beats-per-minute. This means that the performer’s release must anticipate the tempo exactly. As I worked through this etude, I developed a habit of physically exaggerating key releases in order to articulate this timing. 

This precision matters as the etude develops. In Trueman’s quartet 120 BPM for Sō Percussion, hitting a woodblock triggers a metronome in the computer. After performing that piece, I was adept at working with these triggers purely as attacks. Although attacks are frequent in percussion playing, note releases are not. Rhythmic and physically exaggerated key releases on BitKlavier became like another kind of attack for me. They helped me mark my way through the piece and ensure that my timing was accurate.

Example 1—The opening bars of Trueman’s Etude number 1, “Prelude”

Since the sixteenth notes at 100 beats-per-minute are triggered by key releases, their placement in the overall flow of time depends on the performer’s action. There is no other quantizing or time-keeping element in the software that determines where these notes are placed. If the performer doesn’t release at the right moment, the piece will sound uneven.

Towards the end of the etude, careful attention to written duration is necessary. In example 2, the eighth note at the end of each group of sixteenth notes must release right with the beginning of the following pulse. Although it is hard to grasp this from looking at the score, a slightly early release would place those sixteenth notes too early, altering the natural feeling of the quarter note pulse underneath.

To reiterate: the sixteenth note cues in the example will not occur there without a correctly timed release. When we see an electronic element cued in a score, we are accustomed to thinking of it as fixed and immutable, but almost all responsibility with the BitKlavier is in the performer's hands.

Example 2—bars 104-109 of Trueman’s “Prelude.”

The synchronic setting multiplies rhythm. It feels like a coiling and setting loose, especially with the key release trigger. It is not always practical to notate the resulting effects into the score as Trueman does in the first etude. The performer must experiment with the score and the settings to understand how the effects relate to the notes on the page (although it is possible to generate Midi mockups through Sibelius using the BitKlavier as a Virtual Studio Technology).

Example 3 illustrates a section of the fourth etude called “Marbles.” While the first etude contains only one setting, in “Marbles” there are two synchronic settings and two tuning settings, which can exist in any combination of setting/tuning. In this case, the synchronic effects consist of quick falling-off gestures rather than metronomic pulses. This means that the performer is (mostly) dealing with a noisy effect rather than worrying about timing.

Example  3, opening of the fourth Nostalgic Synchronic etude “Marbles”
Trueman builds settings into each piece by assigning keys as buttons, often composing their sound into the work. In “Marbles” the synchronic settings are triggered by the highest C (c8) and lowest A (A0) of the keyboard, which speak as normal notes and also toggle between the two settings. This creates an exciting and dangerous new element of keyboard performance, because the performer always must be in the correct synchronic state. A mis-triggered or double-triggered note flips the settings to the invernse. At first, I struggled with this reality, but gradually I acquired an instinct for fixing the settings mid-performance to get back on track.

This is where adaptability from my percussion practice came in handy: this instrument would most accurately be described as “Marbles BitKlavier,” with unique sounds, potential, and behaviors. It must be learned on it own terms, and the brain must develop a unique map of actions and consequences to navigate it.

In the first versions of BitKlavier, the programming behind these settings was more opaque than it is now, so I mostly discovered these behaviors through trial and error. With the latest version of the program, keymaps are easy to locate and reference to see which keys have been programmed with behaviors. In "Marbles," c7 and c#7 toggle the tuning states, which noticeably shift pitches up and down. These triggers operate the same in both synchronic settings, so the performer also has the potential to be in the right or wrong tuning state at any time.

It took me awhile to build awareness of these digital states into my physical practice, and to know how to hear myself properly inside the piece. I needed to develop an intuition for what each of the possible four permutations sounded like and felt like under my hands. Almost none of this is evident from the score. Too much information about the synchronic settings would likely be visually overwhelming on the page, providing extraneous information which would confuse the performer about which notes mattered for execution. Trueman does indicate which setting is being triggered each time it happens. As the performer becomes adept at switching the states it is easy to know from the score where to be.

Example 4 shows the first synchronic setting for "Marbles." Setting 1 features an extremely fast tempo for the repeated notes (1120 BPM) which creates a blinding stream after each trigger. In contrast to etude 1, these synchronic settings are triggered by the attack rather than the release of the note, so quick staccato strokes are appropriate (and necessary) for executing the patterns. There is no uneven spacing in the synchronic effect (beat multiplier), and the accents of the ten notes increase steadily, providing a sense of momentum rather than falling off.

Example 4—Synchronic setting 1 for “Marbles.”

Setting 2 (example 5) features about half the tempo of repeated notes (580 BPM), an inverse of accents (falling off rather than building), and -- via beat length multipliers -- a gesture akin to a bouncing ball being pulled more rapidly to the ground with each bounce. In the most recent versions of the software, this graphical representation of the settings is helpful. Even without advanced understanding of what each setting does, comparing them side-by-side reveals some sense of how they differ.

Example 5— Setting 2 for “Marbles”
The first note of this synchronic effect is almost exactly a sixteenth note at the tempo of the piece. When I perform sections with setting 2, I always hear this doubling and try to time it in my performance. Setting 1 feels more like an effect - a flurry of notes under my hands -- while setting 2 feels like playing with a metronome.

In the excerpt from the first page of “Marbles” (example 3), what appears to be a consistent texture of steady eighth-notes is actually a rapidly shifting exchange between random flurries and sixteenth note echoes.

Another moment in the piece which highlights this contrast (Example 6) is during the “phasing” section, inspired by the technique of phasing in Steve Reich’s music. The performer phases the right hand of steady eighth notes against the left hand, but at each pivot Trueman switches the synchronic setting via A0. When simultaneous notes phase apart to alternating, and the setting switches from 1 to 2, the resulting patterns resemble Reich’s from works like Piano Phase. By the time he composed “Marbles,” Trueman was writing for me, and he enjoyed throwing in moments like this.

Example 6 — Phasing in “Marbles”


The Nostalgic Setting 


The Nostalgic setting on the BitKlavier manages sound duration and growth in new ways. The most common behavior in this setting is where the note plays "backwards" upon release. This means that the exact attack, duration, and decay play in their reversed versions after the note has been released. For a pianist, this is a new and different way of hearing.

Like the synchronic setting, it also makes sound after the pianist is no longer playing or holding a note. The natural correlation between physical movement and sounding note becomes scrambled. The performer has to imagine sounds still to come based on the digital behaviors of the instrument and incorporate that into their playing.

Two examples from the current repertoire for the instrument illustrate this unique challenge. Dan Trueman’s “Undertow” from the Nostalgic Synchronic etudes uses a preparation that slightly tweaks the playback and then adds another element. Example 7 shows the Nostalgic preparation for this piece. The sound wave image from left to right represents the normal attack and decay of the piano note. Upon release, a cursor moves back towards the left to show the growth of the mirror note.

Example 7 — Nostalgic preparation for “Undertow”
The beige bars above and below show where the Nostalgic playback can be altered and augmented. In the case of “Undertow,” the mirror note stops 200 milliseconds before the peak of the swell and then ricochets back again towards decay for 4000 milliseconds (4 seconds). Trueman calls this an “undertow” effect, and it creates a third note-growth direction to listen for. So for an undertow note: 1) attack/decay;  2) reverse, stopping just short of the peak; 3) decay again for 400 ms.

“Undertow” proceeds at a very slow pace (quarter note equals 40 beats per minute), and the performer is responsible for syncing up timing between all these waves. But the waves are not programmed to follow a certain tempo: they match the duration of the held notes. The pieces could be performed just as easily at 80 BPM or 20 BPM without altering any settings. My own internal sense of timing varies widely with this piece, and I tend to play it too fast.

Example 8 shows a section of “Undertow.” Any musician is used to reading these simple quarter notes and half notes, imagining them to be held for the durations indicated and then released. On the BitKlavier, the performer also needs to factor in the behavior of the current settings. In this case, the written duration with its release only indicates about half of the actual resulting sound. The rapid decay of a piano note also means that the final swell of its mirror image is dramatic at the end of the nostalgic effect.

A kind of nostalgic counterpoint emerges: the attack of each note foregrounds each note as it is struck, and then its reverse swell is equally prominent when it arrives later. The half notes will take twice as long to swell as the quarter notes, so they will return in reverse order.

Example 8 — Mirror notes in “Undertow”

In the book of Microetudes which Trueman commissioned, composers found unusual possibilities within these seemingly simple settings. Nate May’s piece “Cygnet” (Example 9) demonstrates how the direct sound of the instrument and the nostalgic effect can be eerily decoupled. For the performer, it also flips the practice of piano pedaling.

Example 9 — Opening of Nate May’s “Cygnet”
Each key on the BitKlavier can be assigned any combination of behaviors from the available settings. Different effects can happen even within one pattern on one hand. In this case, May silences Bb4, c5, Db5, and Eb5 on the Direct setting, so that the notes don’t speak when pressed (this parameter is called "direct"). This does not mean that they can’t have an effect attached to them! (Example 10)

Example 10 - Nostalgic setting for "Cygnet"

May attaches long nostalgic effects to these notes, which he augments by a duration multiplier of 3, and he provides an undertow tail to each. In the opening bars of the piece, we can see that the “x” noteheads are silent, but since the pedal is down from the beginning, their nostalgic effect is also suppressed until the pedal is released. The performer is playing a consistent sixteenth-note pattern, but only the outer F-natural notes make direct sound (reminiscent of Ligeti’s "touche-blocques" from his piano etudes). Then, when the pedal is released, pent-up nostalgic effects from those muted notes swell gently over the repeated patterns.

The pedal is held down to silence these notes and let up to release their sound. The relationship between aural and physical is scrambled from what a pianist is used to. This is one of the most difficult aspects of the piece. While each harmony lasts for two bars, the pedaling occurs in the middle of each pattern rather than when the harmony change occurs. It took me awhile to get the hang of this new relationship, as my brain kept telling me to lift the pedal on the harmony change.



As a performer, I find variations in tuning to be the easiest to cope with in the Nostalgic Synchronic Etudes. I don’t have perfect pitch, and percussionists are usually more concerned about where to hit something and the timing of the notes than by tuning. Trueman wrote many subtle tuning changes into the Nostalgic Synchronic etudes. Every time I perform them in public people react to their strangeness, while familiarity has made them more comfortable for me.

The greatest challenge comes from situations where tunings change rapidly, such as in the combination of tuning and synchronic settings in Marbles which were previously discussed. In that case, the challenge lies more in accurately triggering settings than in coping with a different tuning.

In the case of “Marbles,” there is one catch that took time to get used to: I am frequently playing a fixed physical pattern when the tuning changes, which means that pitches are changing without me shifting to different notes. This is disconcerting at first, because it circumvents the relationship between physical movement and a change in sound.

The tuning shift provides the sensation of creeping up and down, since it resets between a partial tuning based on a root of C vs. C#. None of this knowledge was essential for me to perform the effects, I just needed to adapt to the sound changing while my fingers repeated the notes on the page. I could imagine this being extremely disorienting for a performer with perfect pitch who is used to mapping a note on the page to an exact frequency.

Software Alteration and Interpretation 


My discussion so far has focused on grappling with the settings of BitKlavier as they are given by the composer. One of the most exciting aspects of the instrument is that the performer can adjust it without any specialized programming skills. Just as I make changes to my percussion setups, I also tinker with small alterations in the BitKlavier settings to optimize my performances.

The performer stumbles upon new insights that aren’t evident to the composer while creating the piece. Also, the BitKlavier is so dynamic that it can be continually tweaked to suit the performer’s strengths.

For instance, it may seem while reading my discussion of the first etude that the fixed tempo of the synchronic setting means that you can’t experiment with tempo. While this is true once a performance is off and running, the tempo can be easily and intuitively adjusted (example 11) during practice. It is easy to set up practice tempi where all the synchronic effects still work in proportion to them, which also means that different performance tempi are possible.

Example 11: tempo for “Prelude” reduced to quarter note equals 90 (each sixteenth note is 360)
As I learn pieces better, my relative sense of tempo changes. When I absorb and especially when I memorize music, I gradually begin to hear the marked tempo as being much slower than when I first encountered the piece. Although there are many reasons to consider and observe the marked tempo, the process of developing an interpretation often leads to small changes. If I wanted to adjust the tempo for the first etude a bit faster as my familiarity increases, it is easy to do so.

I could make other small changes that the composer wouldn’t even  know about. For instance, in “Marbles” I could program several notes at the bottom of the keyboard to flip the synchronic settings back and forth. Even though a wrong note will still sound like a wrong note, if a mistakenly hit B-natural still flips to the right setting I’m in better shape than if I had missed both the note and the setting change. Customization becomes part of learning the instrument.

Finally, learning how to alter settings in the program stimulates a hunger for more creative engagement with it. It is so easy to change settings and immediately hear the consequences that it becomes addictive! Musicians who aren’t accustomed to thinking of themselves as composers will find themselves creating spontaneously and potentially spending hours tinkering with them. In one session, I got carried away with seeing if I could build an accurate machine to perform Reich's piano phase just triggering one note (I could), while in another I set different octaves of the keyboard to trigger metronomes at different tempi and improvised with it.

Reworking Traditional Repertoire 


My interest in the BitKlavier has been geared mostly towards new repertoire, but its usefulness in reexamining older music is one of my favorite aspects of the software. The tuning and synchronic functions allow the performer to reinterpret historical repertoire by excavating its original qualities.

The tuning parameter of BitKlavier achieves what would be impossible with any acoustic instrument: instantaneously changed tuning schemes for the entire instrument. This means that we can hear keyboard repertoire from before Bach’s Well Tempered Clavier in the original tunings. Many music students are only peripherally aware that there ever were different tunings, and so it is a shock to hear the variety of color palettes which we no longer use.

Cristina developed a performance of Frescobaldi’s First Toccata using Trueman’s setting for “quarter comma meantone” tuning, the closest we can guess to the way Frescobaldi’s instruments were tuned. The settings do not only bestow an ancient aura to the music; they provide direct insight into the way the piece is structured. The consonant cadential harmonies are sweeter, while the dissonances are far more dissonant than with an equal temperament keyboard. I felt that I could hear why Frescobaldi would want to lean into those dissonant harmonies, which on a modern instrument sound only mildly so.

These realizations are available to anybody who listens to recordings on instruments which are retuned, but with the BitKlavier the ability to play and hear is available with one change of a setting. Anybody with the program can hear the vast range of colors beyond our modern semi-tone system. 

I have used the synchronic setting to enhance and reinterpret Baroque music, especially J.S. Bach. The ability to set trigger notes means that certain notes in the bass can behave like a basso continuo: struck once, they continue to provide rhythmic and harmonic support while the hands are busy elsewhere. In the one-semester trial course we conducted in 2017, one of Kristin Cahill's students, Jai Raman discovered how this technique could enliven his interpretation of a Bach prelude.

Piano students frequently struggle to develop a good sense of time and pulse. As a percussionist, I developed this skill through ensemble playing, where I got years of feedback from other players about whether my playing was fitting in. The synchronic setting provides a kind of “contextual metronome.” It provides a steady pulse, but the student perceives it as coming from within the performance, rather than from a separate device chirping at them on the music stand.



Cristina has a large piano studio, and we have started incorporating the BitKlavier into her teaching. We, along with Kristin Cahill, already have had two successful efforts at incorporating the instrument with piano students: one was a series of private lessons and masterclasses on learning current rep for the instrument, which culminated in a performance at the Sō Percussion Summer Institute; the other was a semester-long Saturday course which was taught more like classroom piano. Each was an experiment, and we learned much about how the BitKlavier could enhance student’s experience and engage them in new ways.

We have been using several categories of the program with students:
  • Learning the new repertoire for the instrument. In this case, students learn pieces from the Nostalgic Synchronic and Microetudes sets of pieces. The unique characteristics of BitKlavier challenge them to learn a new instrument in a new way. 
  • Enhancing traditional and pedagogical repertoire. Sometimes students struggle just to learn pieces for their main lessons. We’ve sometimes found it difficult to interest them in adding other pieces. We are exploring how adding settings to traditional piano pieces (especially the synchronic) can augment their learning and encourage engagement with repertoire. 
  • Physical disabilities. Cristina currently has several students with physical disabilities, including one with few than ten fingers. The BitKlavier offers the possibilities of expanding the sound world of both original pieces and traditional repertoire for students with physical limitations. For example, it is easy to program arpeggiation over bass notes with varying levels of life-like accents and quirkiness. The student gets more feedback from their music-making and the focus is taken off of what they struggle to do. 
  • Creative composition and improvisation. Once a student starts making their own settings, there is no limit to how far their curiosity can take them. Some kids unsurprisingly learn the program better than we do after only a few weeks or months. They can compose new pieces, and also leave a setting in place and improvise with its possibilities.

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