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Strudel Tutorial - Part 1

Coding music is fun!

Strudel is a tool to make music using JavaScript. You can use to to explore melodies or drum pattern in a coding sort of environment called REPL. But that is just the beginning. Many people use it in live-coding settings called algorave.

Here is a very good example Strudeldudel. Just hit the play button on the upper right.

A basic drum pattern

Let's take Abelton's making music tutorial and try to replicate the drum pattern.

There are four different sequences in this pattern. Each has a total of 16 notes.

A very first and verbose strudel version would look like this:

setcpm(85/4) // make 85 beats per minute (bpm)

let drum = "RolandTR808"

$: s("- - - -  - - - -  - - - -  - - oh -").bank(drum)
$: s("hh hh hh  hh hh hh hh  hh hh hh  hh hh hh hh - -").bank(drum)
$: s("- - - -  cp - - -  - - - -  cp - - -").bank(drum)
$: s("bd bd - -  - - bd -  bd bd - bd  - - - -").bank(drum)
Each of a the $ functions will run in parallel.

The two letter acronyms refer to pieces in a drum set. Here is a list:

bd = bass drum
sd = snare drum
rim = rimshot
hh = hihat
oh = open hihat
lt = low tom
mt = middle tom
ht = high tom
rd = ride cymbal
cr = crash cymbal
cp = clap

A more compact version would just stack up the sequences. In addition, instead of writing out each beat we can just us the beat function to tell strudel what when to play. 

setcpm(85/4) // make 85 beats per minute (bpm)

let drum = "RolandTR808"

$: stack(s("oh").beat("14",16)
      , s("hh").beat("0,1,2,3,4,5,6,7,8,9,10,11,12,13",16)
      , s("cp").beat("4, 12",16)
      , s("bd").beat("0,1,6,8,9,11",16)
     ).bank(drum)

Now, I guess, the "official" strudel version would rather look like this. It is pretty cryptic and harder to read in the beginning. I hope this will ease up over time.

setcpm(85/4) // make 85 beats per minute (bpm)

let drum = "RolandTR808"

$: stack(
  s("~@14 oh ~"),                // Open hi-hat (delayed to step 15)
  s("hh!14 ~ ~"),                // Hi-hats (14 hits, 2 rests)
  s("~ cp ~ cp"),                // Claps (on beats 2 and 4)
  s("[bd!2 ~ ~] [~ ~ bd ~] [bd!2 ~ bd] ~") // Kick pattern in 4 subsequences.
).bank(drum)
  • ~@14 - Extends the rest to last for 14 steps.
  • hh!14 - Repeat hh 14 times

Keyboard shortcuts

It took me forever to figure out how to use the keyboard to start, update, and stop the music. Many website say on MacOS:

  • Cmd + Enter to start and update
  • Cmd + . to stop

But it actually is:

  • Ctrl + Enter to start and update
  • Ctrl + . to stop

At least on my macbook.