sigmdrive

Abstract

Analog "soft clipping" distortion by applying non-linear transfer functions.

Description

sigmdrive simulates analog "soft clipping" by applying non-linear transfer functions. Two different sigmoid equations are implemented.

mode 0

    out = tanh(in * drivefactor)

mode 1

if in > 0    -> out = 1.0 - pow(1. - in, drivefactor)
if in <= 0   -> out = pow(1. + x, drivefactor) - 1.0

Syntax

    aout sigmdrive ain, xdrivefactor, kmode=0

Arguments

• ain: the input audio signal
• xdrivefactor: a k- or a- value, normally greater than 1. A higher value implies more distortion
• kmode: the distortion mode. 0=tanh, 1=pow (see above)

Output

• aout: the distorted audio

Execution Time

• Performance (audio)

Examples

<CsoundSynthesizer>
<CsOptions>
-odac           

</CsOptions>

<CsInstruments>

/* 

    sigmdrive: a sigmoid distortion

    aout sigmdrive ain, kdrive, kmode=0

    kdrive: how much distortion (range 0-inf)
    kmode: 0 = tanh, 1 = pow

*/

sr     = 44100
ksmps  = 64
nchnls = 2
0dbfs  = 1

chn_k "drive", "r"
chn_k "mode", "r"
chn_k "midinote", "r"

chnset 10, "drive"
chnset 1, "mode"

instr 1
    kmidinote chnget "midinote"
    kdrive chnget "drive"
    kmode chnget "mode"     
    ain oscili 0.2, lag(mtof:k(kmidinote), 0.2)
    aout sigmdrive ain, port:k(kdrive, 0.05), kmode
    dispfft aout, 1/20, 2048
    outs aout, aout
endin

</CsInstruments>

<CsScore>

i1 0.1 100

</CsScore>
</CsoundSynthesizer>




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 <height>240</height>
 <visible>true</visible>
 <uuid/>
 <bgcolor mode="background">
  <r>38</r>
  <g>41</g>
  <b>45</b>
 </bgcolor>
 <bsbObject version="2" type="BSBKnob">
  <objectName>drive</objectName>
  <x>140</x>
  <y>0</y>
  <width>80</width>
  <height>80</height>
  <uuid>{72f1554b-6adf-45e3-998d-4d22945dd484}</uuid>
  <visible>true</visible>
  <midichan>0</midichan>
  <midicc>0</midicc>
  <description/>
  <minimum>0.00000000</minimum>
  <maximum>40.00000000</maximum>
  <value>10.00000000</value>
  <mode>lin</mode>
  <mouseControl act="">continuous</mouseControl>
  <resolution>0.01000000</resolution>
  <randomizable group="0">false</randomizable>
  <color>
   <r>245</r>
   <g>124</g>
   <b>0</b>
  </color>
  <textcolor>#f67c00</textcolor>
  <border>1</border>
  <borderColor>#f57c00</borderColor>
  <showvalue>true</showvalue>
  <flatstyle>true</flatstyle>
  <integerMode>false</integerMode>
 </bsbObject>
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  <objectName>mode</objectName>
  <x>265</x>
  <y>50</y>
  <width>80</width>
  <height>30</height>
  <uuid>{092a8810-6562-4cf4-8c3b-6c68ecfdfc1b}</uuid>
  <visible>true</visible>
  <midichan>0</midichan>
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  <description/>
  <bsbDropdownItemList>
   <bsbDropdownItem>
    <name>tan0</name>
    <value>0</value>
    <stringvalue/>
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    <name>pow</name>
    <value>1</value>
    <stringvalue/>
   </bsbDropdownItem>
  </bsbDropdownItemList>
  <selectedIndex>1</selectedIndex>
  <randomizable group="0">false</randomizable>
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  <objectName>graph</objectName>
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  <uuid>{7bdf5122-fdcc-4c85-9f30-0ba8ede6f29a}</uuid>
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  <dispy>1.00000000</dispy>
  <modex>lin</modex>
  <modey>lin</modey>
  <showSelector>false</showSelector>
  <showGrid>true</showGrid>
  <showTableInfo>false</showTableInfo>
  <showScrollbars>true</showScrollbars>
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  <mode>0.00000000</mode>
  <triggermode>TriggerUp</triggermode>
 </bsbObject>
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  <objectName/>
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  <visible>true</visible>
  <midichan>0</midichan>
  <midicc>-3</midicc>
  <description/>
  <label>Drive</label>
  <alignment>center</alignment>
  <valignment>top</valignment>
  <font>Liberation Sans</font>
  <fontsize>16</fontsize>
  <precision>3</precision>
  <color>
   <r>245</r>
   <g>124</g>
   <b>0</b>
  </color>
  <bgcolor mode="nobackground">
   <r>255</r>
   <g>255</g>
   <b>255</b>
  </bgcolor>
  <bordermode>false</bordermode>
  <borderradius>1</borderradius>
  <borderwidth>0</borderwidth>
 </bsbObject>
 <bsbObject version="2" type="BSBKnob">
  <objectName>midinote</objectName>
  <x>25</x>
  <y>0</y>
  <width>80</width>
  <height>80</height>
  <uuid>{5736f449-308c-4301-a80b-70e77923d957}</uuid>
  <visible>true</visible>
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  <midicc>0</midicc>
  <description/>
  <minimum>24.00000000</minimum>
  <maximum>100.00000000</maximum>
  <value>51.41320000</value>
  <mode>lin</mode>
  <mouseControl act="">continuous</mouseControl>
  <resolution>0.01000000</resolution>
  <randomizable group="0">false</randomizable>
  <color>
   <r>245</r>
   <g>124</g>
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  </color>
  <textcolor>#f67c00</textcolor>
  <border>1</border>
  <borderColor>#f57c00</borderColor>
  <showvalue>true</showvalue>
  <flatstyle>true</flatstyle>
  <integerMode>false</integerMode>
 </bsbObject>
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  <width>80</width>
  <height>25</height>
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  <visible>true</visible>
  <midichan>0</midichan>
  <midicc>-3</midicc>
  <description/>
  <label>Midinote</label>
  <alignment>center</alignment>
  <valignment>top</valignment>
  <font>Liberation Sans</font>
  <fontsize>16</fontsize>
  <precision>3</precision>
  <color>
   <r>245</r>
   <g>124</g>
   <b>0</b>
  </color>
  <bgcolor mode="nobackground">
   <r>255</r>
   <g>255</g>
   <b>255</b>
  </bgcolor>
  <bordermode>false</bordermode>
  <borderradius>1</borderradius>
  <borderwidth>0</borderwidth>
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</bsbPanel>
<bsbPresets>
</bsbPresets>

See also

• tubeharmonics
• distort1
• tanh
• powershape

Credits

Eduardo Moguillansky, 2019

(based on pd/else's drive~ - https://github.com/porres/pd-else)