Clavia Nord Lead 2X User Manual page 86

11. Synthesis basics: The oscillators and waveforms
In the first, the jump happens 5% in from the beginning of the period. This is referred to as a pulse wave
with a 5% pulse width (sometimes called duty cycle). The second wave has a pulse width of 10%. The third
wave has a pulse width of 50%.
This third wave is a special case of the pulse wave, called a square wave, and this has one peculiarity, it
only contains odd number harmonics, which gives it a "hollow" quality.
On many synthesizers (including the Nord Lead) the pulse width can be adjusted, to set the timbre of
the pulse wave. The more narrow the pulse width, the more "thin" the sound will be.
You can also have the pulse width vary continuously, for example from an LFO or envelope. This is re-
ferred to as pulse width modulation. Modulating pulse widths from an LFO creates a rich, chorus-like ef-
fect often used in "string" sounds.
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Above we have only discussed spectra where the overtones appear at perfect harmonics. While this is true
for the basic waveforms discussed above, it is definitely not true for all sound. If you for example use the
frequency modulation (FM) or Ring Modulation capabilities in the Nord Lead 2X, with the two oscilla-
tors set to an "unusual" interval (not octaves or fifths, for example), you will get a spectrum where the
overtones appear at frequencies somewhere between the perfect harmonics. This results in an inharmonic
sound, which often sounds "metallic".
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One some instruments (including the Nord Lead 2X), two Oscillators can be synchronized. If you for ex-
ample synchronize Oscillator 2 to Oscillator 1, Oscillator 2 will start over with a new period of the wave-
form, each time Oscillator 1 does so. If Oscillator 2 then has a higher frequency than 1, it will get a
complex waveform that depends both on its own pitch and on that of the other oscillator.
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NORD LEAD 2X V1.0x