Operation Manual

4.4 The Osc Module 31

4.4 The Osc Module

Depending on the sound engine used, Ultra Analog Session uses

one or two oscillators. In the case where one oscillator is used, the

Detune knob of the Osc module is used to change the frequency of the

output signal from the oscillator. In the case where two oscillators are

used, the Detune knob is used to change the frequency of the second

oscillator relative to that of the ﬁrst oscillator. This is useful to make the

sound richer.

Depending again on the engine used, the second knob of the Osc module will

be labeled Sub or Ratio and control the amount of sub oscillator signal or a hard

synchronization mode of the oscillators. In sub-oscillator mode, a second signal,

one octave lower than the pitch of the oscillator, is generated and added to the

original signal of the oscillator resulting in a richer sound. The amount of sub-

oscillator signal added to the original signal is controlled with the Sub knob. When

in its leftmost position, the sub-oscillator is muted and turning this knob clockwise

increases the amount of sub-signal.

The sync mode refers to the possibility of resetting, or in other words restart,

the signal of the oscillator at each cycle of a synchronization signal. In this mode,

the frequency of the clock is that of the oscillator and the frequency of the oscillator

signal is varied. The perceived pitch is that of the original oscillator signal but the

harmonic content of the signal is modiﬁed by the synchronization operation. The

ratio between the frequency of the oscillator and the synchronization frequency is

controlled with the Ratio knob. When in its leftmost position the synchronized

signal has the same frequency as that of the clock and turning this knob clockwise

increases this frequency.

4.5 The Filter Module

Depending on the sound engine used, a low-pass, high-pass

or bandpass ﬁlter is applied to the signal from the oscillator. The

behavior of this ﬁlter is controlled with the Filter module. The

Cutoff knob is used to control the cutoff frequency of the ﬁlter

while the Q knob is used to control its resonance. The cutoff fre-

quency of the ﬁlter can further be modulated by an envelope sig-

nal controlled from the Env section of the module. When playing

a note, the cutoff frequency of the ﬁlter will move from the value

determined by the settings of the Cutoff knob, and come back to its this original