The KEY control on the FILTER ZOOM page is identical to the KEY slider on the LAYER pages. The Filter Key Tracking is a dedicated modulation control. It determines to what extent the cutoff frequency will track the keyboard. The higher the KEY value is set, the more the filter will open in the upper range of the keyboard and close in the lower ranges of the keyboard.
For example, if a low pass filter is loaded and the cutoff is set below 1.00KHz, the notes played below Middle C will become increasingly darker in tone, and keys above Middle C will be increasingly brighter. At the minimum setting, higher and lower notes have no effect on the cutoff frequency.
KEY INVERT SWITCH
The KEY INVERT switch on the FILTER ZOOM page is identical to the KEY INVERT switch on the LAYER pages. Key Tracking can be inverted simply by selecting the word “Key” below the control. This switch will change to inverted text when Key tracking is inverted and the sonic result will be the opposite of standard Filter Key Tracking.
NOTE: Because of how the scaling of the Metal Pipe -/+ or Resonator -/+ filters works, in order to get these filters to respond with playable pitches the Key Tracking knob should be fully-open and the Invert switch enabled.
KEY TRACKING OCTAVE SWITCHES
The small LED switches above the Key Tracking knob are the Key Tracking Octave Switches. These switches transpose Filter Key Tracking up or down 2 octaves, the middle switch being the standard tracking. You will find these offsets most useful when using the Resonator and Metal Pipe filters.