GAIA Exploring Sound (PDF) - Roland Corporation Australia

Now let’s look at the Spectrum of a Square waveform.
Figure 11.11 Spectrum of Square
waveform
Figure 11.12 Spectrum of Noise,
variation one
Clearly the waveform is not an exact mathematical square wave,
and for the same reasons as the previous sawtooth waveform.
Indeed, you can see that the odd Harmonics are all louder which
gives the waveform it’s characteristic “square” sound, but the
even Harmonics also feature.
The first thing you can see is the lack of a clear Harmonic
structure. The sound is made up of a totally random set of
Harmonics. They appear to occur anywhere and everywhere.
Figure 11.13 Spectrum of Noise,
variation two
Noise
Now let’s examine the Noise waveforms.
Initialize the Patch and select the Noise waveform.
Try the three different variations of Noise. Why do they sound so
different?
Let’s put the first variation through a Spectrum Analyzer. The
result would be as shown in Figure 11.12.
Now let’s look at the second variation.
Although similar, this variation looks and sounds quite different to
the first. The Harmonics still appear to occur across all
frequencies, but more so in the low frequency range than the
higher ranges.
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