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Nord Wave User Manual v1.1
the second wave has a pulse width of 50%.
this second example 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 Wave) 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 referred to as
pulse width modulation. Modulating pulse widths from an
LFo creates a rich, chorus-like effect often used in “string”
sounds.
About in-harmonic spectra
We have only discussed spectra where the overtones ap-
pear at perfect harmonics so far. 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 modula-
tion (FM, PM) capabilities in the Nord Wave, with the two
oscillators 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 in-harmonic sound, which
often sounds “metallic”.
Sync
one some synthesizers, one oscillator can be synchronized
to another. If you for example synchronize oscillator 2 to
oscillator 1, oscillator 2 will start over with a new period of
the waveform, 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.
When sync is applied, the basic pitch of oscillator 2 is
locked to that of oscillator 1. If you change the pitch of os-
cillator 1 you will affect the basic pitch of both oscillators.
Furthermore, when you vary the pitch of the synchronized
oscillator (oscillator 2), this will be perceived as a change in
timbre, rather than in pitch.
this leads to a spectrum with deep resonances at osc2’s
harmonics, like this:
If you go even further and let the pitch of the synchronized
oscillator vary continuously, for example from an LFo or
envelope, you will change the harmonic content of the
sound in an interesting and very characteristic way.
The Filter
the filter in a synthesizer is used to remove or emphasize
frequencies in a spectrum. a filter is a bit like an amplifier
(a volume control) that is applied differently to different
parts of the spectrum. For example, a filter might make low
frequencies louder, while at the same time making high
frequencies weaker. applying such a filter would make a
sound have more bass and less treble.
Let’s imagine a sound with a spectrum where all harmonics
are available at full level. It would look like this:
Let’s now pass this spectrum through a lowpass filter (this
type of filter is discussed in more detail below).
the filter has a characteristic, which can be drawn as a
curve.
time
time
Frequency
amplitude
amplitude
amplitude
amplitude
Frequency
