Second stage - Tone shaping & Filters

Shaping Tone in Subtractive Synthesis

Now that we have a basic understanding of how to generate tone, let's explore how to shape that tone.

Understanding Waveforms

The waveforms we've discussed are our raw material. We wouldn't want every sound we produce to simply sound like:

• A square wave
• A sawtooth wave

The Role of Filters

To change these sounds, we use a filter. The purpose of a filter in subtractive synthesis is to remove portions of the signal, specifically, portions of the frequency spectrum, that are being sent from the oscillators.

After filtering:

• A rich-sounding sawtooth wave can become a smooth, warm sound by eliminating the high-end information through filtering.

Examples

• Sawtooth Wave without a Filter:

  (Insert audio example)

• Sawtooth Wave with a Filter:

  (Insert audio example)

Filter Controls

The filter section of most subtractive synthesizers will contain two primary controls:

1. Cutoff Frequency (often abbreviated to 'cutoff')

   • Cutoff refers to where the filter is cutting off:
     • Higher frequencies (if you're using a high cut filter)
     • Lower frequencies (if you're using a low cut filter)

2. Resonance

   • Resonance allows you to take a set of frequencies and boost them, resulting in a much more resonant sound.