Set the tempo

use_bpm  bpm (number)

Sets the tempo in bpm (beats per minute) for everything afterwards. Affects all subsequent calls to sleep and all temporal synth arguments which will be scaled to match the new bpm. If you wish to bypass scaling in calls to sleep, see the fn rt. Also, if you wish to bypass time scaling in synth args see use_arg_bpm_scaling. See also with_bpm for a block scoped version of use_bpm.

For dance music here’s a rough guide for which BPM to aim for depending on your genre:

Introduced in v2.0

Example

# Example 1 


  4.times do
    play 50, attack: 0.5, release: 0.25
    sleep 1
  end
  sleep 2 
 
  use_bpm 120 
  4.times do
    play 62, attack: 0.5, release: 0.25
    sleep 1
  end
  sleep 2
 
  use_bpm 240 
  8.times do
    play 62, attack: 0.5, release: 0.25
    sleep 1
  end





# default tempo is 60 bpm
 
# attack is 0.5s and release is 0.25s
# sleep for 1 second
 
# sleep for 2 seconds
# Let's make it go faster...
# double the bpm
 
# attack is scaled to 0.25s and release is now 0.125s
# actually sleeps for 0.5 seconds
 
# sleep for 1 second
# Let's make it go even faster...
#  bpm is 4x original speed!
 
# attack is scaled to 0.125s and release is now 0.0625s
# actually sleeps for 0.25 seconds