Can someone build an efficient drum machine?

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Hey @ds604, just stumbled across this, and really like it as a very short & simple yet still visually intuitive drum machine.

Here’s an even shorter version, inspired by yours:

use_bpm 120

def beats(pat)
  pat.delete(' ').split('').map(&:to_i).ring
end

patt = {
  :bd_klub         => "9--5 --5- ---- -3-- 9--- ---- 9--- ----",
  :drum_snare_soft => "---- ---3 9--- ---- ---- ---- --33 9---",
  :perc_snap2      => "9--- --11 11-- ---- 5--- 5-11 11-- 9---",
  :elec_flip       => "--5- ---- --5- --5- --5- ---- --5- --5-",
  # :bd_boom => "9-3--"
}

live_loop :main do
  tick  #(step: [0,1,1,1,1,1,2].choose)  # change step of tick randomly for nice effect
  patt.each{ |key, val|  sample key, amp: beats(val).look / 10.0  }
  sleep 0.25
end

Turning the beat numbers directly into amplitudes makes it easy to control accents for each beat. I also used a loop to play each sample, shortened the beat-parsing function, and folded the separate instruments hash into keys of the pattern hash.

Thanks for a drum machine short and clear enough to teach in a class session!

Update: okay, I think this is the shortest and clearest version I can come up with. Gets rid of the pattern hash entirely; everything is laid out in the loop body (this makes it easier to control the volume of each instrument individually, for example by adding “* 0.5” at the end of one of the “amp:” values:

def pat(p)
  p.delete(' ').split('').map{ |v|  v.to_f / 10  }.ring
end

live_loop :machine do
  use_bpm 60
  tick
  sample :bd_klub,         amp: pat(" 9--5 --5- ---- -3-- ").look
  sample :drum_snare_soft, amp: pat(" ---- ---3 9--- ---5 ").look
  sample :perc_snap2,      amp: pat(" 9--- --11 11-- ---- ").look
  sample :elec_flip,       amp: pat(" --5- ---- --5- --5- ").look
  sleep 0.25
end
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