Welcome to Aratu

▶ Open in Aratu to hear the examples, change them and do the exercises

Aratu is a way to write music on the computer keyboard and hear it at once. You write the way a musician thinks: in bars, beats, notes and chord symbols. Press Listen, and the music plays. Change a letter, and the music changes with it.

This book teaches Aratu from the start, one idea at a time. You do not need to know how to program. Knowing a little music helps, but music is learnt here too.

How this book works

Each lesson explains one idea with examples you can hear and change as much as you like. If you make a mess, press Start over.
Under each example there is a grid: the bars, the numbered beats and each symbol where it sounds, the way a teacher would draw it on the board. You can work on it: drag a symbol to another place, click an empty place to add one and a symbol to take it away, and the text changes with it.
The exercises ask you to write something. Hear how it should sound plays the goal; Check compares what you wrote with the goal by its sound and says, bar by bar, where they differ.
When something is written wrong, Aratu explains it in a musician's words, never as a "syntax error".

Your progress is kept in this browser, and the list of lessons shows a ✓ beside each lesson you finish.

The first sound

Press Listen:

Try it▶ Hear it in Aratu

hh = c c c c

This is one bar of hi-hat with four hits. hh is the line's name, and each c is a hit of the closed hi-hat. The bar repeats until you press Stop. Everything in Aratu repeats like this, as a loop.

Change one of the cs to o and listen again: o is the open hi-hat. You can change the text while the music plays; the change comes in at the start of the next bar.

More than one line

Each drum has its own line. Listen to the three together:

Try it▶ Hear it in Aratu

hh = c c c c
bd = b - b -
sd = - s - s

bd is the bass drum and sd the snare drum. A - is a rest: on that beat, that drum does not play. Bass drum on 1 and 3, snare on 2 and 4: the most common beat in rock and pop.

Your first exercise

Write a snare line that plays on all four beats. Hear the goal first, then change the rests and press Check.

Exercise▶ Hear it in Aratu

sd = - - - -

See an answer

sd = s s s s

In the next lesson you will see what a bar is to Aratu, and how to set the tempo.

In English, Portuguese or Spanish

Aratu's words can be written in English, Portuguese or Spanish, and even mixed. This book uses the English words, which are the shortest and the ones you will see in examples from all over the world. These two pieces sound the same:

Try it▶ Hear it in Aratu

meter: 3/4
tempo: 120
bd = b - -

Try it▶ Hear it in Aratu

compasso: 3/4
andamento: 120
bd = b - -

The second one is in Portuguese; in Spanish it would be compás: 3/4 and pulso: 120. Note names work the same way: c4 or dó4. The manual has the whole table of words in the three languages.

Do you program, and want to know how Aratu works underneath? The Inside tab gives each thing its technical name: what a line is, a block, an at bar.