Play That Thing

Trading fours

You and the soloist take four bars each. Press the red disc to start with Armstrong. On your turn, tap the keys, use A through ; on your keyboard, or select Hum to sing into your mic. Use headphones for that. Your notes appear on the you line in the chart, followed by the soloist’s reply. The suggestion above the keys gives you a phrase to start with.

Choose Dodds or Ory below the keys, alongside the Memory control. “Lead the band” has the tempo, swing and stop-time controls. Each player’s part is editable in the chart.

The solo models

The models use eight Armstrong solos, six Dodds solos and five Ory solos, recorded between 1925 and 1928. That’s about two thousand notes from the Weimar Jazz Database, transcribed by hand by researchers at the Liszt School of Music. All the solos are transposed to B-flat here, with their rhythms and chord information preserved.

The model searches those solos for a sequence matching your last few notes, then uses what came next to build its reply. It does this one note at a time, favoring notes that fit the current chord. The method follows François Pachet’s Continuator. Your phrases are added after your first turn, so later replies can quote you too.

Memory

Memory sets the length of the sequence used for matching. Stitch uses one note, which allows more jumps between solos. Quote uses five and tends to keep longer phrases from a recording together. Mix falls between the two. The clock’s outer ring names the source recording; the strip below the keys shows its year and the position in the track.

Calling the band

Calls change the band’s parts at the next bar. Each call edits the code in the chart, where you can adjust it further. This borrows from TidalCycles and Strudel, as well as the shouted directions on old jazz records. The name comes from “Oh, play that thing!” in “Dipper Mouth Blues.”

The chart

The chart has one row per player and twelve bars grouped in fours. Tap a bar to move horn notes by a half step, add rests or change the piano and banjo rhythms. Chords are editable too: Edim in bar 6 and G7 in bar 8 are two common older blues changes. You can also type directly into the code for a bar or the full line underneath it.

The clock

The red arm makes one rotation every twelve bars. Each instrument has its own ring: pitch increases outward, and a note’s tail shows its duration. Yellow ticks mark the second eighth note of each beat. More swing moves those ticks later in the beat.

Reading the code

Steps share a bar’s time evenly, so "x x x x" gives you four evenly spaced strums. The notation borrows from TidalCycles and Strudel.

d5

A note name followed by its octave. Use b for a flat or # for a sharp. Middle C is c4.

~

Silence for one step.

[a b]

Fit several steps into the time of one step.

<a b c>

Play a different item each bar, cycling through the list. The twelve-bar blues pattern uses this.

a@3

Make a step last three times as long. a _ _ does the same thing.

a!3

Repeat a step three times. Inside < >, three bars in a row.

a*2

Repeat a step twice in the same amount of time.

[a, b]

Play both at once.

db5>d5

Start on one note and slide to the other.

Bb7

Set the chord for the piano and banjo on the chord line.

x

Piano or banjo: play the chord.

1 3 5

On the piano, play the first, third or fifth chord tone in the bass.

Swing

Swing delays the second eighth note of each beat. A 2:1ratio gives the first note two thirds of the beat and the second one third. Players vary this with tempo. Friberg and Sundström measured ratios near 3.5:1 at slower tempos, moving toward even eighths at faster tempos.

The sounds

All the instruments are synthesized in the browser. The brass uses a sawtooth wave that brightens with volume, with a small slide into each note and vibrato. The clarinet uses odd harmonics and wide vibrato to approximate Johnny Dodds’s sound.

The banjo and piano use Karplus–Strong synthesis: a short noise burst loops through a delay and loses brightness on each pass. Two slightly detuned strings per piano note add the wobble of an old upright.

The band

The lineup follows Louis Armstrong’s original Hot Five: Armstrong on cornet, Johnny Dodds on clarinet, Kid Ory on trombone, Lil Hardin Armstrong on piano and Johnny St. Cyr on banjo. They started recording in Chicago in November 1925. The accompaniment was written for this experiment. The solo parts come from the transcription models.

The palette borrows Kandinsky’s associations between color and sound: yellow for trumpet, light blue for flute, and vermilion for brass and tuba.

The records

Two recordings are included. In “The St. Louis Blues” (Columbia, 1925), Armstrong’s cornet answers Bessie Smith’s singing. In “Dipper Mouth Blues” (Okeh, 1923), he plays second cornet in King Oliver’s band. Both stream from Wikimedia Commons and are in the public domain in the United States.

Sources

• The Jazzomat Research Project, Weimar Jazz Database, version 2.1 (2017). The note data used here comes from the database and is shared under the Open Database License ↗.
• Martin Pfleiderer, Klaus Frieler, Jakob Abeßer, Wolf-Georg Zaddach and Benjamin Burkhart, eds., Inside the Jazzomat: New Perspectives for Jazz Research (Schott Campus, 2017).
• François Pachet, “The Continuator: Musical interaction with style,” Journal of New Music Research 32, no. 3 (2003): 333–341.
• Alain de Cheveigné and Hideki Kawahara, “YIN, a fundamental frequency estimator for speech and music,” Journal of the Acoustical Society of America 111, no. 4 (2002): 1917–1930.
• Anders Friberg and Andreas Sundström, “Swing ratios and ensemble timing in jazz performance: Evidence for a common rhythmic pattern,” Music Perception 19, no. 3 (2002): 333–349.
• Kevin Karplus and Alex Strong, “Digital synthesis of plucked-string and drum timbres,” Computer Music Journal 7, no. 2 (1983): 43–55.
• Alex McLean, “Making programming languages to dance to: live coding with Tidal,” FARM ’14 (ACM, 2014).
• Wassily Kandinsky, Concerning the Spiritual in Art (1911).
• Gunther Schuller, Early Jazz: Its Roots and Musical Development (Oxford University Press, 1968).