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Signal Modifiers: Standard Filters

tonex, atonex, resonx

  ar      tonex      asig, khp[, inumlayer, iskip]
  ar      atonex     asig, khp[, inumlayer, iskip]
  ar      resonx     asig, kcf, kbw[, inumlayer, iscl, iskip]

Description

tonex, atonex and resonx are equivalent to fliters consisting of more layers of tone, atone and reson, with the same arguments, serially connected. Using a stack of a larger number of filters allows a sharper cutoff. They are faster than using a larer number instances in a Csound orchestra of the old opcodes, because only one initialization and k- cycle are needed at time, and the audio loop falls enterely inside the cache memory of processor.

Initialization

inumlayer – number of elements in the filter stack.. Default value is 4.

iskip – initial disposition of internal data space. Since filtering incorporates a feedback loop of previous output, the initial status of the storage space used is significant. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.

iscl – coded scaling factor for resonators. A value of 1 signifies a peak response factor of 1, i.e. all frequencies other than kcf are attenuated in accordance with the (normalized) response curve. A value of 2 raises the response factor so that its overall RMS value equals 1. (This intended equalization of input and output power assumes all frequencies are physically present; hence it is most applicable to white noise.) A zero value signifies no scaling of the signal, leaving that to some later adjustment ( see balance). The default value is 0.

Performance

asig – input signal

khp – the response curve's half-power point. Half power is defined as peak power / root 2.

kcf – the center frequency of the filter, or frequency position of the peak response.

kbw – bandwidth of the filter (the Hz difference between the upper and lower half-power points)

Author

Gabriel Maldonado (adapted by John ffitch)
Italy
New in Csound version 3.49


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Signal Modifiers: Standard Filters