Elektron Analog Four - Manual (Page 67)

MORE ON OSCILLATORS, FILTERS AND ENVELOPES
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MORE ON OSCILLATORS, FILTERS AND ENVELOPES
In this chapter the functionality of the oscillators, filters and envelopes will be explained in further detail.
OSCILLATORS
Several waveforms are available to the two oscillators of each synth track. By adjusting the PW parameter, the
waveshape can be changed on all types of waveforms, changing their timbre. Furthermore, each oscillator has
a dedicated PWM LFO, giving animation to the sound by means of pulsewidth modulation.
SAW. This waveform has a biting, buzzy and distinct sound. It contains all harmonics, both odd and even, of the
fundamental frequency. Classic synth basses, strings and brass sounds are often created using sawtooth wave-
forms. The PW parameter brings in a second sawtooth, out of phase with the first one. Changing the PW value
or engaging PWM varies the phase difference between the two, similar to having two slightly detuned oscillators
running. This is useful to get a thicker sawtooth sound with more movement as different harmonics interfere with
each other. To get a regular single sawtooth, set PW to mid position or either extreme value.
TRANSISTOR PULSE Transistor pulse is special sort of pulse waveform, suitable when you want to achieve
acid-like sounds. It sounds a bit more shrill compared to the regular pulse waveform available to the oscillators.
PW sets the width of the upper and lower parts of the wave, just like on the regular pulse waveform described
below. The major difference is that one part of the transistor pulse waveform is not flat, but rather sloping a bit,
thus displaying a slightly similar form as a sawtooth waveform. This introduces more even harmonics, making
the sound less hollow. Extreme PW settings, positive or negative, will mute the waveform as the upper or lower
part disappears completely. A change in pitch also changes the waveform and pulsewidth a bit, giving slightly
different sound at different pitches.
PULSE When the PW parameter is set to its middle value of 0, a square wave will be produced. A square wave
contains only odd-numbered harmonics of the fundamental frequency and has a hollow sound, not quite as full
as a sawtooth waveform. Changing the PW makes the pulse waveform asymmetric, introducing even harmonics
and making the sound thinner and more nasal. Using PWM to introduce pulsewidth modulation is the most clas-
sic way of adding animation to a synthesizer waveform. When you want to recreate the sounds of old video
games, square waves are very handy. Extreme PW settings, positive or negative, will mute the waveform, as the
upper or lower part disappears completely.
TRIANGLE A triangle waveform has a mellow and dampened sound, reminiscent of a mix between a pure sine
wave and a square wave. A triangle wave contains only odd-numbered harmonics, but at lower levels than a
square wave. A low-pass filtered triangle wave will sound very much like a sine wave. The PW parameter intro-
duces an edge in the waveform, gradually changing it from a pure triangle at mid position to a reversed sawtooth
waveform at extreme PW settings.
SUB OSCILLATORS
Each oscillator features a sub oscillator, running at a fixed interval below the oscillator. By activating a sub oscil-
lator, more depth and body will be added to the sound. The sub oscillators work as an extension of the regular
oscillator pitch, but will however not be affected by neither waveshaping nor pulse width modulation. Four sub
oscillator waveforms exist.
1OCT This option will add a square waveform one octave below the root note. The sub oscillator frequency is 1/
2 of the oscillator frequency.
2OCT This option will add a square waveform two octaves below the root note. The sub oscillator frequency is 1/
4 of the oscillator frequency.
2PUL This option will add a 25% pulse waveform two octaves below the root note. This selection sounds a bit
similar to mixing the 1OCT and 2OCT types.