9
FM Attenuverter: The FM Attenuverter determines the depth of
frequency modulation applied to the cutoff/centre frequency.
• Turning the knob clockwise will increase the depth of exponential
frequency modulation.
• Turning the knob anticlockwise will increase the depth of
exponential frequency modulation with inverted polarity.
• Centring the knob will attenuate the control voltage signal.
1V/Oct Input: The 1V/Oct Input is a bipolar control voltage input for
the cutoff/centre frequency.
• This is a dedicated exponential frequency control input which
can be used for precise frequency modulation such as ‘keyboard
tracking’.
• If I-ō47 is self-oscillating, the 1V/Oct Input can be used for
consistent pitch tracking of the sine waveform, effectively making
I-ō47 a quadrature sine waveform oscillator.
• Control voltage is summed with the level set by the Coarse and
Fine knobs.
Notch: The Notch knob controls the centre frequency offset of the notch
response output. This parameter affects the Notch Output only.
The numbers surrounding the Notch knob depict a multiplier indicating
an approximate octave offset from the centre frequency.
• ¼ = 0.25 x centre frequency (-2 octave offset). [towards high
pass response]
• ½ = 0.5 x centre frequency (-1 octave offset). [towards high
pass response]
• 1 = centre frequency (0 octave offset). When the knob is set to 1, the
Notch Output is a traditional symmetrical notch filter.
• 2 = 2 x centre frequency (+1 octaves offset). [towards low
pass response]
• 4 = 4 x centre frequency (+2 octave offset). [towards low
pass response]
