Synths - add decay_curve opt to sc808 closed hihat

Author: samaaron

app/server/ruby/lib/sonicpi/synths/synthinfo.rb

@@ -4601,7 +4601,8 @@ def arg_defaults
           :lpf_slide => 0,
           :lpf_slide_shape => 1,
           :lpf_slide_curve => 0,
-          :decay => 0.42
+          :decay => 0.42,
+          :decay_curve => -30
         }
       end
 
@@ -4613,6 +4614,12 @@ def specific_arg_info
             :validations => [v_positive(:decay)],
             :modulatable => false
           },
+          :decay_curve =>
+          {
+            :doc => "Curve value for the decay of the hi-hat",
+            :validations => [],
+            :modulatable => false
+          }
           :lpf =>
           {
             :doc => "Low pass filter cutoff value for the hi-hat. A MIDI note representing the highest frequencies allowed to be present in the sound. A low value like 30 makes the sound round and dull, a high value like 100 makes the sound buzzy and crispy.",

etc/synthdefs/compiled/sonic-pi-sc808_closed_hihat.scsyndef

@@ -474,6 +474,7 @@ SynthDef('sonic-pi-sc808_closed_hihat', {|
   lpf = 121.05875888638981, lpf_slide = 0, lpf_slide_shape = 1, lpf_slide_curve = 1,
 
   decay=0.42,
+  decay_curve = -30,
   out_bus = 0|
 
   var sig, sighi,siglow, sum, env, osc1, osc2, osc3, osc4, osc5, osc6;
@@ -483,7 +484,7 @@ SynthDef('sonic-pi-sc808_closed_hihat', {|
   hpf = hpf.varlag(hpf_slide, hpf_slide_curve, hpf_slide_shape);
   lpf = lpf.varlag(lpf_slide, lpf_slide_curve, lpf_slide_shape);
 
-  env = EnvGen.kr(Env.perc(0.005, decay, 1, -30),doneAction:2);
+  env = EnvGen.kr(Env.perc(0.005, decay, 1, decay_curve),doneAction:2);
   osc1 = LFPulse.ar(203.52);
   osc2 = LFPulse.ar(366.31);
   osc3 = LFPulse.ar(301.77);