LinPlug Spectral - Manual (Page 67)

Filter
The Drive dial (Saturation) enables you to set the amount of filter drive or
distortion. This can be used to create a distorted sound.
The Cutoff dial is used to set the operation frequency of the filter. The Filter
Type menu right of the Resonance dial allows you to select one of four filter
types:
– LP12 = Low Pass 12 dB
– HP12 = High Pass 12 dB
– BP12 = Band Pass 12 dB
– BR12 = Band Reject 12 dB
The Resonance dial is used to set the amount of emphasis around the
cutoff frequency. Higher settings create a more pronounced peak in the
signal while lower settings produce a flatter response.
Next is a Volume control to adjust the level after the filter, as sometimes it
might be desired to reduce it a bit especially when applying heavy Drive
and/or Resonance or raise it after filtering a lot of the original signal.
The filter's cutoff frequency can be modulated using the Mod Rate and Mod
Depth controls.
The Mod Rate dial allows you to set the rate at which the filter's cutoff
frequency is modulated. The modulation rate is displayed in Hz, the display
also functions as a Sync menu.
The Mod Depth control is used to set the depth to which the filter's cutoff
frequency is modulated.