Help/UGens/Filters/AmpComp.html

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  30 <p class="p1"><span class="s1"><b>AmpComp</b></span><span class="s2"><span class="Apple-tab-span">      </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></span><b>basic psychoacoustic amplitude compensation</b></p>
  31 <p class="p2"><br></p>
  32 <p class="p2"><br></p>
  33 <p class="p1">superclass: UGen</p>
  34 <p class="p2"><br></p>
  35 <p class="p3"><span class="s3"><span class="Apple-tab-span">    </span>implements the (optimized) formula: <span class="Apple-tab-span">        </span></span>compensationFactor = (root / freq) ** exp<span class="Apple-converted-space"> </span></p>
  36 <p class="p2"><span class="Apple-tab-span">     </span></p>
  37 <p class="p1"><span class="Apple-tab-span">     </span>Higher frequencies are normally perceived as louder, which AmpComp compensates.<span class="Apple-converted-space"> </span></p>
  38 <p class="p2"><span class="Apple-tab-span">     </span></p>
  39 <p class="p1"><span class="Apple-tab-span">     </span>see also <a href="AmpCompA.html"><span class="s4">AmpCompA</span></a></p>
  40 <p class="p2"><br></p>
  41 <p class="p1"><b><span class="Apple-tab-span">  </span>*ar(freq, root, exp)</b></p>
  42 <p class="p1"><b><span class="Apple-tab-span">  </span>*kr(freq, root, exp)</b></p>
  43 <p class="p1"><b><span class="Apple-tab-span">  </span>*ir(freq, root, exp)</b></p>
  44 <p class="p2"><span class="Apple-tab-span">     </span></p>
  45 <p class="p1"><span class="Apple-tab-span">     </span><b>freq</b> <span class="Apple-tab-span">        </span><span class="Apple-tab-span">    </span>input frequency value. For freq == root, the output is 1.0.</p>
  46 <p class="p1"><span class="Apple-tab-span">     </span><b>root</b><span class="Apple-tab-span"> </span><span class="Apple-tab-span">    </span>root freq relative to which the curve is calculated (usually lowest freq)</p>
  47 <p class="p1"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>default value: C (60.midicps)</p>
  48 <p class="p1"><span class="Apple-tab-span">     </span><b>exp</b><span class="Apple-tab-span">  </span><span class="Apple-tab-span">    </span>exponent: how steep the curve decreases for increasing freq (see plots below)</p>
  49 <p class="p1"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>default value 0.3333</p>
  50 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></p>
  51 <p class="p1"><span class="Apple-tab-span">     </span>Note that for frequencies <b>very much smaller than root </b>the amplitudes can become very high.<span class="Apple-converted-space"> </span></p>
  52 <p class="p1"><span class="Apple-tab-span">     </span>In this case limit the freq with <b>freq.max(minval)</b>, or use AmpCompA.</p>
  53 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></p>
  54 <p class="p4"><span class="Apple-tab-span">     </span></p>
  55 <p class="p2"><br></p>
  56 <p class="p4"><br></p>
  57 <p class="p5"><br></p>
  58 <p class="p5"><br></p>
  59 <p class="p6">// compare a sine without compensation</p>
  60 <p class="p4"><br></p>
  61 <p class="p7">{ <span class="s5">SinOsc</span>.ar(<span class="s5">MouseX</span>.kr(300, 15000, 1)) * 0.1 }.play;</p>
  62 <p class="p4"><br></p>
  63 <p class="p6">// with one that uses amplitude compensation</p>
  64 <p class="p7">(</p>
  65 <p class="p7">{<span class="Apple-converted-space"> </span></p>
  66 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">var</span> freq;</p>
  67 <p class="p7"><span class="Apple-tab-span">     </span>freq = <span class="s5">MouseX</span>.kr(300, 15000, 1);</p>
  68 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">SinOsc</span>.ar(freq) * 0.1 * <span class="s5">AmpComp</span>.kr(freq, 300)<span class="Apple-converted-space"> </span></p>
  69 <p class="p7">}.play;</p>
  70 <p class="p7">)</p>
  71 <p class="p4"><br></p>
  72 <p class="p4"><br></p>
  73 <p class="p6">// different sounds cause quite different loudness perception,<span class="Apple-converted-space"> </span></p>
  74 <p class="p6">// and the desired musical behavior can vary, so the exponent can be tuned:</p>
  75 <p class="p7">(</p>
  76 <p class="p7">{<span class="Apple-converted-space"> </span></p>
  77 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">var</span> freq;</p>
  78 <p class="p7"><span class="Apple-tab-span">     </span>freq = <span class="s5">MouseX</span>.kr(300, 15000, 1);</p>
  79 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">Pulse</span>.ar(freq) * 0.1 * <span class="s5">AmpComp</span>.kr(freq, 300, 1.3)<span class="Apple-converted-space"> </span></p>
  80 <p class="p7">}.play;</p>
  81 <p class="p7">)</p>
  82 <p class="p4"><br></p>
  83 <p class="p6">// the curves:</p>
  84 <p class="p4"><br></p>
  85 <p class="p7">// exp = 0.3333</p>
  86 <p class="p7">(200,210..10000).collect {<span class="s5">|freq|</span> (200/freq) ** 0.3333 }.plot;</p>
  87 <p class="p4"><br></p>
  88 <p class="p6">// nearly linear for semitone steps:</p>
  89 <p class="p4"><br></p>
  90 <p class="p7">(48..72).midicps.collect {<span class="s5">|freq|</span> (48.midicps/freq) ** 0.3333 }.plot;<span class="Apple-converted-space"> </span></p>
  91 <p class="p7">{ <span class="s5">AmpComp</span>.ar(<span class="s5">Line</span>.ar(48, 72, 1).midicps, 48.midicps) }.plot(1.0);</p>
  92 <p class="p4"><br></p>
  93 <p class="p6">// exp = 1.2</p>
  94 <p class="p7">(200,210..10000).collect {<span class="s5">|freq|</span> (200/freq) ** 1.2 }.plot;</p>
  95 <p class="p7">(48..72).midicps.collect {<span class="s5">|freq|</span> (200/freq) ** 1.2 }.plot;</p>
  96 <p class="p7">{ <span class="s5">AmpComp</span>.ar(<span class="s5">Line</span>.ar(48, 72, 1).midicps, 48.midicps, 1.2) }.plot(1.0);</p>
  97 <p class="p4"><br></p>
  98 <p class="p4"><br></p>
  99 <p class="p6">// amplitude compensation in frequency modulation</p>
 100 <p class="p7">(</p>
 101 <p class="p7">{<span class="Apple-converted-space"> </span></p>
 102 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">var</span> freq;</p>
 103 <p class="p7"><span class="Apple-tab-span">     </span>freq = <span class="s5">MouseX</span>.kr(300, 15000, 1);</p>
 104 <p class="p7"><span class="Apple-tab-span">     </span>freq = freq * <span class="s5">SinOsc</span>.ar(<span class="s5">MouseY</span>.kr(3, 200, 1), 0, 0.5, 1);</p>
 105 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">SinOsc</span>.ar(freq) * 0.1 * <span class="s5">AmpComp</span>.ar(freq, 300)<span class="Apple-converted-space"> </span></p>
 106 <p class="p7">}.play;</p>
 107 <p class="p7">)</p>
 108 <p class="p4"><br></p>
 109 <p class="p6">// without amplitude compensation</p>
 110 <p class="p7">(</p>
 111 <p class="p7">{<span class="Apple-converted-space"> </span></p>
 112 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">var</span> freq;</p>
 113 <p class="p7"><span class="Apple-tab-span">     </span>freq = <span class="s5">MouseX</span>.kr(300, 15000, 1);</p>
 114 <p class="p7"><span class="Apple-tab-span">     </span>freq = freq * <span class="s5">SinOsc</span>.ar(<span class="s5">MouseY</span>.kr(3, 200, 1), 0, 0.5, 1);</p>
 115 <p class="p7"><span class="Apple-tab-span">     </span><span class="s5">SinOsc</span>.ar(freq) * 0.1</p>
 116 <p class="p7">}.play;</p>
 117 <p class="p7">)</p>
 118 <p class="p4"><br></p>
 119 <p class="p6">// in granular synthesis:</p>
 120 <p class="p7">(</p>
 121 <p class="p8">SynthDef<span class="s6">(</span><span class="s7">"pgrain"</span><span class="s6">,<span class="Apple-converted-space"> </span></span></p>
 122 <p class="p7"><span class="Apple-tab-span">     </span>{ <span class="s5">arg</span> out = 0, sustain=0.01, amp=0.5, pan = 0;</p>
 123 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>var freq = MouseX.kr(300, 7000, 1);</p>
 124 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>var window = <span class="s5">Env</span>.sine(sustain, amp * <span class="s5">AmpComp</span>.ir(freq));</p>
 125 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">Out</span>.ar(out,<span class="Apple-converted-space"> </span></p>
 126 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">Pan2</span>.ar(</p>
 127 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">SinOsc</span>.ar(freq),</p>
 128 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>pan</p>
 129 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>) * <span class="s5">EnvGen</span>.ar(window, doneAction:2)</p>
 130 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>)</p>
 131 <p class="p7"><span class="Apple-tab-span">     </span>}</p>
 132 <p class="p7">).send(s);</p>
 133 <p class="p7">)</p>
 134 <p class="p4"><br></p>
 135 <p class="p6">// send grains</p>
 136 <p class="p7">(</p>
 137 <p class="p7">fork {</p>
 138 <p class="p7"><span class="Apple-tab-span">     </span>loop {</p>
 139 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>s.sendBundle(0.1, [<span class="s8">\s_new</span>, <span class="s8">\pgrain</span>, -1,1,1]);</p>
 140 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>0.02.wait;</p>
 141 <p class="p7"><span class="Apple-tab-span">     </span>};</p>
 142 <p class="p7">}</p>
 143 <p class="p7">)</p>
 144 <p class="p4"><br></p>
 145 <p class="p4"><br></p>
 146 <p class="p6">// try different synth defs:</p>
 147 <p class="p5"><br></p>
 148 <p class="p4"><br></p>
 149 <p class="p6">// without AmpComp:</p>
 150 <p class="p4"><br></p>
 151 <p class="p7">(</p>
 152 <p class="p8">SynthDef<span class="s6">(</span><span class="s7">"pgrain"</span><span class="s6">,<span class="Apple-converted-space"> </span></span></p>
 153 <p class="p7"><span class="Apple-tab-span">     </span>{ <span class="s5">arg</span> out = 0, sustain=0.01, amp=0.5, pan = 0;</p>
 154 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">var</span> freq = <span class="s5">MouseX</span>.kr(300, 7000, 1);</p>
 155 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">var</span> window = <span class="s5">Env</span>.sine(sustain, amp);</p>
 156 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">Out</span>.ar(out,<span class="Apple-converted-space"> </span></p>
 157 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">Pan2</span>.ar(</p>
 158 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">SinOsc</span>.ar(freq),</p>
 159 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>pan</p>
 160 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>) * <span class="s5">EnvGen</span>.ar(window, doneAction:2)</p>
 161 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>)</p>
 162 <p class="p7"><span class="Apple-tab-span">     </span>}</p>
 163 <p class="p7">).send(s);</p>
 164 <p class="p7">)</p>
 165 <p class="p4"><br></p>
 166 <p class="p6">// with AmpCompA</p>
 167 <p class="p7">(</p>
 168 <p class="p8">SynthDef<span class="s6">(</span><span class="s7">"pgrain"</span><span class="s6">,<span class="Apple-converted-space"> </span></span></p>
 169 <p class="p7"><span class="Apple-tab-span">     </span>{ <span class="s5">arg</span> out = 0, sustain=0.01, amp=0.5, pan = 0;</p>
 170 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">var</span> freq = <span class="s5">MouseX</span>.kr(300, 7000, 1);</p>
 171 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">var</span> window = <span class="s5">Env</span>.sine(sustain, amp * <span class="s5">AmpCompA</span>.ir(freq));</p>
 172 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">Out</span>.ar(out,<span class="Apple-converted-space"> </span></p>
 173 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">Pan2</span>.ar(</p>
 174 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="s5">SinOsc</span>.ar(freq),</p>
 175 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>pan</p>
 176 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>) * <span class="s5">EnvGen</span>.ar(window, doneAction:2)</p>
 177 <p class="p7"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>)</p>
 178 <p class="p7"><span class="Apple-tab-span">     </span>}</p>
 179 <p class="p7">).send(s);</p>
 180 <p class="p7">)</p>
 181 <p class="p4"><br></p>
 182 <p class="p4"><br></p>
 183 </body>
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