Parametric EQ CHOP
The Parametric EQ CHOP filters an audio clip using "parametric equalizer" type controls, and then applies other audio effects. The functions, in the order they are applied, are:
- Parametric Filter - Filters any frequency range of the input, using center frequency, bandwidth, filter gain, pass gain, filter shape and dropoff parameters.
- Sideband Filter - Filters the input with another audio channel's power spectrum (contained in the second input).
- Pitch Shift - Shifts the pitch of an audio clip (the first input), maintaining the same duration. Pitch shifting is not available in time slice mode.
- Echo Generator - Adds echoes to the audio clip.
Filter Animation Channels - The third input is the Filter Animation Channels, which allows the filter parameters to be changed over the CHOP's interval. See Filter Animation Channels. For example, to animate the Center Frequency, create a CHOP containing an animated channel named "center", and attach it to the third input.
Parameters - Filter Page
This boosts or reduces the audio in a frequency range. The center frequency, frequency width, filter gain, pass gain, filter shape and dropoff are independently controllable.
Filter Channels - Turns the parametric equalizer filter effect on or off (but not the other special functions).
Center Frequency - Defines the center frequency of the filter. This frequency will have a gain equal to that of the Filter Gain.
Bandwidth - Defines how many octaves around the center frequency is affected by the filter. When the filter is shaped as a Gaussian or a triangular filter, the filter gain drops off from the center frequency along the Gaussian or triangular curve. At a bandwidth of 1, frequencies half an octave above and below the center frequency will be filtered out according to Pass Gain.
Filter Gain - Defines the gain of the filter. The audio in the frequency range of the filter is multiplied by the Filter Gain. The audio within the band is multiplied by Filter Gain.
Pass Gain - Defines the gain of the frequencies outside the filtered region. If zero, frequencies outside the range are not audible. The audio outside the band is multiplied by Pass Gain.
Filter Shape - The shape of the filter can be a box, triangle, a gaussian, or any interpolation between. A value of zero produces a pure box, 0.5 produces a pure triangle, and 1 produces a Gaussian shape. Values between 0 and 0.5 produce a filter that is a combination of a box and a triangle, and so on.
Box filters have abrupt drop-offs. Triangular filters have gradual linear drop-offs, with discontinuities at the corners. Gaussian filters have smooth drop-offs.
Filter Dropoff - The shape of the filter can be further modified by changing its dropoff. At one, the filter shape is typical, dropping about 6dB per octave. Values below 1 cause the filter to dropoff more slowly. Values above 1 cause the filter to dropoff rapidly.
Parameters - Sideband Page
Sideband Filter - Which method to use when sideband filtering: Average Power Spectrum, or Continuous Power Spectrum.
Filter Type - The power spectrum of a sideband filter can be used to enhance frequencies.
- Sideband Pass - Enhances frequencies.
- Sideband Stop - Removes frequencies.
Sideband Gain - The gain of the sideband filter.
Base Gain - The base gain of the channel.
Sideband Effect - The frequency effect of the filter.
Parameters - Pitch Page
Pitch Adjust - Turns pitch shifting on or off.
Octave Shift - The pitch of a sound can be shifted up to half an octave up or down by this function. This is expressed in octaves. Note that the more a pitch is shifted, the more it is distorted. A value of zero does not affect the sound.
Pitch Chunk - The chunk size at which Octave Shift resamples. Mainly used to fine tune the sound once the correct pitch is found.
Parameters - Echo Page
Echo - Turns echoes on or off.
Pre Echoes - Specifies the number of echoes that precede the actual sound. (Note that pre echoes are not a naturally occurring phenomenon).
Pre Echo Delay - Specifies the delay between the pre-echoes (in either seconds, frames or samples, depending on the setting of the Units ).
Pre Echo Dropoff - Going back in time, the pre-echoes reduce in magnitude. Pre-Echo Dropoff is the portion of the last pre-echo's magnitude that the current pre-echo's magnitude is. A value of 1 means that all pre-echoes will be equal in magnitude, while a value of 0.5 will produce pre-echoes of magnitudes 0.5, 0.25, 0.125... of the original sound.
Post Echoes / Post Echo Delay / Post Echo Dropoff - Post echoes are naturally occurring echoes: the echoes occur after the original sound. The parameter descriptions are the same as for pre-echoes.
Remainder - See Remainder Options
Parameters - Digital Page
See the Digital Filter Overview in the Pass Filter CHOP for a full description of digital filters and the parameters on this page.
Standard Options and Local Variables
Local Variables: $I $C, $NC