Special Waveform - Button
When the Special button in the Oscillator Section is pressed the Display shows:
The parameter is “Special waveform” In this case with a value of Double saw.
This parameter determines what special waveform the currently selected oscillator is going to have. Use the lower Data knob to
adjust this parameter. If this parameter is set to Audio input (1), Audio input 1 will be substituted for the standard Oscillator. If this
parameter is set to Audio input (2), Audio input 2 will be substituted for the standard Oscillator. If this parameter is set to Double
saw the Double saw waveform as described above will be substituted for the standard Oscillator. The range of this parameter is
Audio input (1), Audio input (2) & Double saw. This parameter is memorised with a Program.
How to use the Double Saw waveform
Width - Button
Level - Knob
When the Double Saw wave is selected the Width part of the matrix is used to control the “Difference” in phase between the 2 Saw
waves. The Level control controls the static phase difference between the 2 Saw waves. When this is set to 000 there is no differ-
ence between the waves & so at this setting Double Saw waves sound just the same as a standard Saw wave.
As both waves are adding together exactly when no phase difference is set between the 2 Saw waves the resulting “Single” Saw
wave is twice as loud as a standard Saw wave. This can be handy when severe filtering is being employed.
When this parameter is set to a positive value the phase difference between the 2 Saw waves is modulated by a positive amount.
Similarly negative values produce a negative phase shift between the 2 Saw waves. Fully clockwise or fully anticlockwise the
phase shift is 180˚ has been shifted positive or negative respectively. The range of this parameter is -64 to +63. This parameter is
memorised with a program.
The key way to understand how this works is to understand that detuning can be expressed as a continually accelerating ( or
decelerating ) phase shift. When looking at the waves of detuned Oscillators on an oscilloscope it can be clearly seen that one
waveform accelerates ( or decelerates, the result is the same ) in respect to the other. The greater the detuning the greater the dif-
ference in phase shift acceleration or deceleration between the two Oscillators.
So how is this done? The answer is with an LFO. Because the modulation of an LFO has been tailored to modulate a Double Saw
wave exactly from 0˚ phase shift to 360˚ when set to FULLY positive or negative modulation ( 180˚ phase shift of modulation of
each positive & negative cycle are used providing 360˚ of phase shift ) continuous detuning effects can be reproduced.
To create straight pitch shift detuning effects use a Saw wave on the modulating LFO. Moderate speed is required. Typically 110
when set to “Slow”. Slow speeds produce small pitch shifts. Fast speeds produce large ones.
To create chorus like detuning effects use a Tri wave on the modulating LFO. Fairly slow speeds are all that is required.
Anything less than FULL positive or negative modulation will result in less than 360˚ phase shift & clicks will occur.
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