12. Synthesis basics: The oscillators and waveforms
NORD MODULAR G2 V1.1
Page 206
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.
A
A
A
A
B
B
B
BO
O
O
OU
U
U
UT
T
T
T
I
I
I
I
N
N
N
NH
H
H
HA
A
A
AR
R
R
RM
M
M
MO
O
O
ON
N
N
NIIIIC
C
C
C
S
S
S
S
P
P
P
PE
E
E
EC
C
C
CT
T
T
TR
R
R
RA
A
A
A
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 Modular G2, with two oscil-
lators 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”.
S
S
S
S
Y
Y
Y
YN
N
N
NC
C
C
C
One some instruments (including the Nord Modular G2), two Oscillators can be
synchronized
. 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 Oscillator 1 you will affect the basic pitch of both oscillators. Furthermore, when you vary the
