User Manual

17
The number and relative strengths of a sound’s harmonic
frequencies determine its tone color or timbre. Subsequent 25
contains a Filter for removing certain frequencies from audio
signals. Because filtering gives you control over an audio signal’s
harmonic content, it physically alters the waveform being filtered.
Subsequent 25 uses the classic Moog lowpass Ladder Filter with
four selectable slopes (see Hidden Parameters on page 30).
Lowpass filters pass all frequencies up to a point called the Cutoff
frequency and gradually roll off, or attenuate, frequencies above
that point. You can change the Cutoff manually using a knob, or
you can change it by applying a signal from a control source such
as an Envelope or LFO.
Turning the Cutoff all the way down closes the Filter so that nothing
passes through it. Raising the Cutoff opens the Filter. As you turn
the CUTOFF knob clockwise from its lowest position, first you’ll hear
only the audio signal’s lowest frequencies, and then the timbre will
grow gradually brighter. The Filter Envelope, in combination with the
CUTOFF knob’s setting, is the Filter’s primary control source.
Another characteristic of the Subsequent 25 Filter is Resonance.
Resonance increases the level of audio frequencies closest to
the Cutoff frequency by making the Filter roll off frequencies
less gradually. It regenerates those frequencies by feeding them
back to the Filter. Turning up the Resonance emphasizes harmonics
closest to the Cutoff frequency and exaggerates any changes to
the Cutoff frequency.
FILTER CONTROLS
CUTOFF: The Cutoff frequency of the Filter is controlled by this knob. Its lowest setting is 20Hz, which
effectively closes the Filter and doesn’t allow any audio to pass through. Its highest setting is 20kHz,
which opens the Filter completely and allows all audio to pass through.
RESONANCE: Rotating this knob controls how much signal is routed from the Filter output back to
its input. Turning it clockwise increases the Resonance, causing a peak in amplitude at the Cutoff
frequency. Settings above 7 cause the Filter to self-oscillate.
MULTIDRIVE: MultiDrive acts as the Subsequent 25 distortion processor, offering effects ranging from
asymmetrical, tube-like warmth to aggressive hard clipping, with a smooth continuous transition in
between. The MULTIDRIVE knob controls how hard you drive the OTA and FET stages, which are located
between the Filter and the Amplifier in the signal path. The higher the setting, then the more aggressive
the clipping effect. Varying amounts of MultiDrive can give your sounds a distinct tonal edge, as well as
make them more responsive to changes in Filter Resonance, waveform, and Oscillator level.
EG AMOUNT: This knob determines how much the Filter Envelope modulates the Filter’s Cutoff
frequency. In other words, EG AMOUNT controls the depth of the Envelope Generator’s effect
on the Filter.
Notice that the EG AMOUNT knob is bipolar, meaning that its control value is positive when it’s turned
up and negative when it’s turned down. Turning it clockwise from center causes the Envelope to raise
the Cutoff frequency from the CUTOFF knob’s setting. Turning it counterclockwise from center causes
the Envelope to lower the Cutoff frequency from the CUTOFF knob’s setting.
FILTER