A Filter and Even More Drum Machine

Pulled from the ever informative SuperCollider Users Mailing List is this fine little example of an interesting low pass filter courtesy of nonprivate,  aka DJ Cylob.

"

this is kind of nice,

here's the normal sort of lpf:

(
{ 
var f;
f = FSinOsc.kr(1, 0, 24, 84).midicps;
RLPF.ar(Saw.ar(70,0.2), f, 0.3)
}.play
)

but with this combo of lpf and mid eq, the bass disappears as the resonance increases, which is a bit more like a real filter.

(
{ 
var f;
f = FSinOsc.kr(1, 0, 24, 84).midicps;

MidEQ.ar(
 LPF.ar(Saw.ar(70,0.2), f), 
 f, 

 0.5, 18, 0.6
) 

}.play
)
"

Inspired by this I decided to see if I could use it on my drum machine and at the same learn how to send the output of a pattern through an effect. 

Here's the code I came up with, adapted from the Pbind help file which covers this very topic. 

(
SynthDef(\drums, {|out = 0, bassLevel = 0 , snareLevel = 0, hatLevel = 0, tomLevel = 0, pan1 = 0, pan2 = 0, pan3 = 0, pan4 = 0|

 var env1, env2, env3, env4, bass, snare, hat, tom, bassOut, snareOut, hatOut, tomOut, mixer; 
 env1 = EnvGen.kr(Env.perc(0.001, 0.2, 1, -4), 1, doneAction:2);
 env2 = EnvGen.kr(Env.perc(0.001, 0.5, 1, -1), 1, doneAction:2);
 env3 = EnvGen.kr(Env.perc(0.002, 0.3, 1, -2), 1, doneAction:2);
 env4 = EnvGen.kr(Env.perc(0.001, 0.1, 1, -5), 1, doneAction:2); 
 bass = SinOsc.ar(80) + Crackle.ar(1, 0.5);
 bassOut = Pan2.ar(bass*env1, pan1, bassLevel);
 
 snare = SinOsc.ar(120) - WhiteNoise.ar(0.5, 0.5);
 snareOut = Pan2.ar(snare*env4, pan2, snareLevel); 
 
 hat = Klank.ar(`[ [ 6563, 9875 ],
  [ 0.6, 0.5 ],
  [ 0.002, 0.003] ], PinkNoise.ar(1)); 
 hatOut = Pan2.ar(hat*env3, pan2, hatLevel); 
 
 tom = SinOsc.ar(440); 
 tomOut = Pan2.ar(tom*env4, pan4, tomLevel); 
 
 mixer = Mix.new([bassOut, snareOut, hatOut, tomOut]); 
 
 
 Out.ar(out, mixer);
 
 }).store
 
 )
   
 

 (
  SynthDef("lpfandmideq", { arg out;  
 var audio, efx, f;
 f = SinOsc.kr(3, 0, 24, 84).midicps; 
 audio = In.ar(20,2);
 efx= MidEQ.ar(
 LPF.ar(audio, f), 
 f, 

 0.5, 18, 0.6
); 
 
 Out.ar(out, efx);
}).memStore;  
  )
   
  (  
  a = Synth.after(1, "lpfandmideq");  
  )  
   
   
  (
   
   
  

 a = Pseq ([1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0]);
 b = Pseq ([0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0]);
 c = Pseq ([0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0]);
 d = Pseq ([0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]); 
 e = Pwhite (0.14, 0.16, inf);
 
 p = Pbind(
  \instrument, \drums,
  \out, 20,
  \dur, e,
  \bassLevel, Pseq ([a], inf), 
  \snareLevel, Pseq ([b], inf),
  \hatLevel, Pseq ([c], inf),  
  \tomLevel, Pseq ([d], inf)
   
  ).play;
   
   
  )  

 To make this work you will need to make sure that you evaluate each section in brackets separately, apart from that it's pretty striaghtforward really.

In setting up the effect synth I needed to make sure that I set the input bus and the number of channels,  this needs two beacuse the drum machine is a two channel synth

audio = In.ar(20,2);

then create an instance of this synth

(  
  a = Synth.after(1, "lpfandmideq");  
  )  

and finally set the output of my pattern to the same bus that I set as the input of my effect. 

\out, 20,

and that's Jazz. 

Surprisingly easy really and it doesn't sound too bad.