Nailing that classic PWM bass sound

1

The sound of the original Pro One was renowned for its bass presence and throaty growl when opening up the filter, and the updated Pro-1 is no different. One sound commonly used for that is a pulse-width modulating bass sound.

2

Let’s recreate that patch on the Pro-1 and make use of both oscillators and their individual pulse widths. Start by turning on the square wave for Osc A, with the pulse width set to 5. Set the octave to 0, and make sure frequency is set to 0.

3

For Oscillator B, we’re going to make use of both the triangle and pulse width waves – set both switches to On. Just like for Osc A, set the octave to 0, the Frequency as close to 0 as you can get it, and the lo freq switch off.

4

Set pulse width to 6.5 and play a few notes with the filter wide open. You’ll hear thick, rich overtones as the two pulse waves rub against each other; a chorus-like effect. Triangle wave adds a lower harmonic and fills out the bottom end nicely.

5

In the Mixer section, set both Oscs to 7.5. You’ll notice the response of the filter is a tad more aggressive when levels are dimmed. Keeping them lower gives a mellower sound, which works with a sound that already has a lot of harmonic content.

6

As this is a bass sound, we want to tame a lot of those high frequencies with the filter. Set the cutoff to 3.5, resonance to 1, and both Env and Keyboard to 5. Playing with the Filter envelope shape, especially decay, gives timbral variation.