Aratu music written to play, and to change while it plays

Changes in the right place

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

In the last lesson the music changed when you changed the text. Often, though, the change is decided ahead of time: the fill in bar 8, the drums dropping out in the chorus, the bass changing in the second part. This lesson shows how to mark each change at the bar, and even the beat, where it should happen.

At a bar: at bar

A line that starts with at bar 9: happens at bar 9. Without it, the line holds from the start of the piece.

Try it▶ Hear it in Aratu
tempo: 110
pattern groove { hh = cc cc cc cc; bd = b - b -; sd = - s - s }
pattern fill   { sd = ss ss SS SS; bd = b - - - }
play groove
at bar 4: play fill
at bar 5: play groove

The groove plays in bars 1, 2 and 3; the fill in bar 4; the groove comes back in bar 5.

Just once: once

Going back to the groove after a fill is so common that it has a shortcut. With once at the end, the pattern plays one time and whatever was playing before comes back by itself:

Try it▶ Hear it in Aratu
tempo: 110
pattern groove { hh = cc cc cc cc; bd = b - b -; sd = - s - s }
pattern fill   { sd = ss ss SS SS; bd = b - - - }
play groove
at bar 4: play fill once

Playing live, now: play fill once brings the fill in at the very next beat, and the groove comes back at the bar where it would have been.

On a beat of the bar: beat

A fill often starts in the middle of a bar. at bar 4 beat 3: comes in on the third beat of bar 4:

Try it▶ Hear it in Aratu
tempo: 110
pattern groove { hh = cc cc cc cc; bd = b - b -; sd = - s - s }
pattern fill   { sd = ss ss SS SS; bd = b - - - }
play groove
at bar 4 beat 3: play fill once

Listen: the first two beats of bar 4 still belong to the groove, and the fill takes the last two. beat 2.5 falls halfway between beats 2 and 3.

For a stretch: from bar … to …

from bar 5 to 6: holds for those bars only. At bar 7 what held before comes back, without you writing anything:

Try it▶ Hear it in Aratu
tempo: 110
drums { hh = cc cc cc cc; bd = b - b -; sd = - s - s }
bass = | c2 _ g1 _ |
from bar 3 to 4: drums: out

The drums drop out in bars 3 and 4 and come back in bar 5. It works for everything: dynamics, tempo, patterns, parts coming in and going out.

A line that changes at a bar

A line's own music can change at a bar too. The new line starts from its beginning, at the marked bar:

Try it▶ Hear it in Aratu
tempo: 100
bass = | c2 _ g1 _ | a1 _ e1 _ |
hh = cc cc cc cc
at bar 5: bass = | f1 _ f2 _ | g1 _ g2 _ |

In bars 1 to 4 the bass plays the first line, twice; from bar 5 on, the second. That is how to write a piece with different parts without needing sections.

Lengths in beats

Every change that takes time (cresc, rit, accel, tempo ramps) accepts lengths in bars (bars), beats (beats), eighth notes (eighths) or sixteenths (sixteenths):

Try it▶ Hear it in Aratu
tempo: 90
melody = | c4 d e f | g _ _ _ |
at bar 2: melody: cresc to ff over 3 beats

Exercises

Make the fill play once, at bar 3, and the groove come back by itself.

Exercise▶ Hear it in Aratu
pattern groove { hh = cc cc cc cc }
pattern fill   { sd = ss ss SS SS }
play groove
See an answer
pattern groove { hh = cc cc cc cc }
pattern fill   { sd = ss ss SS SS }
play groove
at bar 3: play fill once

Now the fill starts on beat 3 of bar 2.

Exercise▶ Hear it in Aratu
pattern groove { hh = cc cc cc cc }
pattern fill   { sd = ss ss SS SS }
play groove
at bar 2: play fill once
See an answer
pattern groove { hh = cc cc cc cc }
pattern fill   { sd = ss ss SS SS }
play groove
at bar 2 beat 3: play fill once

Take the drums out in bars 2 and 3 only, with a single line.

Exercise▶ Hear it in Aratu
drums { hh = c c c c }
bass = | c2 _ _ _ |
See an answer
drums { hh = c c c c }
bass = | c2 _ _ _ |
from bar 2 to 3: drums: out

From bar 3 on, the bass plays | f2 _ c2 _ |.

Exercise▶ Hear it in Aratu
bass = | c2 _ g1 _ |
See an answer
bass = | c2 _ g1 _ |
at bar 3: bass = | f2 _ c2 _ |