Sonic Pi

1 Synths

Learn It

Synths is short for Synthesizers.
Where as the samples you were using in the previous lesson were prerecorded sounds, synths are algorithmically generated sounds.
This means that synths can be of any pitch, and we can then play around with their parameters as much as we like.

Code It

Try this:

use_synth :dark_ambience
play 60

So that is middle C, played with the synth dark_ambience

Learn It

Synths have lots of parameters we can use.
For instance, pan: will control which speaker the sound comes from. -1 is the left speaker and 1 is the right speaker

Code It

Try this:

use_synth :dark_ambience
play 60, pan: -1
sleep 0.5
play 60, pan: 0
sleep 0.5
play 50, pan: 1

Learn It

There are many other parameters that we can use with the synths.
- Attack
- Sustain
- Release
The default duration of a synth is 1 beat (which is 1 second at the moment)
The Attack parameter decides how long it takes for the synth to reach it's normal volume.
The Sustain parameter decides how long the note will last.
The Release parameter decides how long the note will take to reach a zero volume.

Code It

Try this - it will play the synth for 3 seconds.

use_synth :dark_ambience
play 60, sustain: 3

Now this - it will now play the synth for 6 seconds.

use_synth :dark_ambience
play 60, attack: 3, sustain: 3

This will play the synth for a total of 9 seconds

use_synth :dark_ambience
play 60, attack: 3, sustain: 3, release: 3

2 Threads

Learn It

In the previous lesson you made a bass line.
What if we want to play a bass line and then have synths playing over the top?

Code It

Copy and paste this into the Sonic Pi window.

use_synth :fm
16.times do
  sample :drum_bass_hard, amp: 0.8
  sleep 0.25
  play :e2, release: 0.2
  sample :elec_cymbal, rate: 12, amp: 0.6
  sleep 0.25
end

Learn It

Now let's create a melody to be played over the top of the bass line, using synths.

Code It

Add this onto the end of your code.

use_synth :tb303
64.times do
  play chord(:e3, :minor).choose, amp: 0.25
  sleep 0.125
end

Listen to the track you've made.

Learn It

The melody track you've created doesn't start playing until after the bass track has finished.
We want the two to play simultaneously.
That's where threads come to the rescue.

Code It

Modify your code so it looks like this:

in_thread do
  use_synth :fm
  16.times do
    sample :drum_bass_hard, amp: 0.8
    sleep 0.25
    play :e2, release: 0.2
    sample :elec_cymbal, rate: 12, amp: 0.6
    sleep 0.25
  end
  sleep 4
end

use_synth :tb303
64.times do
  play chord(:e3, :minor).choose, amp: 0.25
  sleep 0.125
end

Now we can see that the bass track plays along with the melody track.

Badge It

Using threads, produce a piece of music with bass and melody tracks.