Poly Grid - Basic Subtractive Synth
Let’s leave the Note Grid behind for a while, because honestly, I could show you about two million patches you can make with it, and that would obviously go way beyond the scope here. So, I’d say we move on to the Poly Grid and build our first synthesizer.
Add a new Poly Grid #
Add a new Poly Grid Device after the Note Grid or remove the Note Grid and replace it with a new Poly Grid!
When you open the Poly Grid for the first time, the default patch is already a basic subtractive synthesizer. You’ve got an oscillator, an amplitude envelope, and an output. What’s missing, though, is a filter and maybe swapping the sine oscillator for a saw oscillator. Let’s make those changes.
Step 1: Swap the Oscillator #
- Right-click on the Sine Oscillator.
- In the dropdown menu, you’ll see a list of modules that you can replace it with.
- Select the Saw option to replace the sine wave with a sawtooth wave.
A sawtooth wave has a rich harmonic content compared to the pure tone of a sine wave, which has no overtones at all. With more overtones, you can subtract frequencies, which is the essence of subtractive synthesis.
Step 2: Add a Filter #
To subtract harmonics, we’ll need a filter:
- Drag a Sallen-Key Low-Pass Filter module into the Grid and place it after the Oscillator.
- Adjust the filter’s Frequency knob to set the cutoff frequency. Anything above this cutoff will be dampened, and anything below it will pass through. This is why it’s called a low-pass filter.
- You can change the "filter mode" below the frequency knob. The "P" stands for pole. The more poles a filter has, the steeper the frequency falloff.
Step 3: Maintain the Envelope and Output #
- After the filter, leave the Amplitude Envelope in place to shape the sound’s volume over time.
- Ensure the final output is connected to the Audio Out module.
What You’ve Built #
This setup gives you a basic subtractive synthesizer where you can remove harmonics from the sawtooth wave using the low-pass filter. The Amplitude Envelope then shapes how the sound fades in and out.
Polyphony Settings #
As a quick reminder, if you click on an empty area in the Grid or select the Poly Grid device itself, you can access the Inspector on the left side of the screen. Here, you can adjust the polyphony settings:
- Polyphonic: Allows you to play multiple notes simultaneously, ideal for chords and pads.
- Monophonic: Limits the synth to one voice at a time, perfect for basslines or lead sounds where only one note is active.
Conclusion #
Congratulations! You’ve expanded the default patch into a proper subtractive synthesizer. By replacing the sine wave with a sawtooth wave and adding a low-pass filter, you now have a flexible synth capable of subtracting harmonics from a rich waveform. Keep experimenting with the filter and envelope settings to explore its possibilities!
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