Adding Vibrato

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Vibrato can be added to most wind instruments. In our pipe model, we can add vibrato at several different places, adding interest to an otherwise-dull sound.

In the patch below, vibrato is created with an LFO. The LFO signal can be added to the model in three different places: the pitch, the input air pressure, and the pipe’s LPF frequency. These destinations can be chosen using the three purple Mixer modules in the center column. Patch variations 2 through 4 demonstrate different kinds of vibrato.

Modulating the pitch

Variation 2 modulates the pitch by routing the LFO to the comb filter’s pitch input.

Modulating the air pressure

Variation 3 modulates the input air pressure. This doesn’t affect the pitch, but creates an amplitude modulation effect that is more pleasing than simple tremolo.

Modulating the frequency of the pipe’s lowpass filter

Variation 4 modulates the frequency of the pipe’s LPF loop filter. This does something interesting: it seems to affect the pitch, the loudness, and the brightness all at the same time. And it does. When the filter’s frequency is lowered, three things happen:

1. The sound gets duller. Higher harmonics are removed from the signal.
2. The sound gets softer. This happens for the same reason as above.
3. The pitch of the instrument drops. This is because lowering the filter’s frequency increases the number of effective samples, making the loop slightly longer. Notice that this effect is more pronounced on higher notes, which have fewer samples in the loop. If we wish, we can even this out by placing a LevelScaler Module with a negative slope between the mixer and the filter’s frequency input (we’ll demonstrate this later).