Shift Distortion Implementation


(Artie Fufkin) #1

I’m trying to emulate the shift distortion with a VST. I’m using the Robin Schmidt FuncShaper VST with an absolute value function and high pass filter(to get rid of DC offset). Getting close, but there’s just a little bit of extra grit with the shift distortion, even when I’m just about matching levels.

Can anybody shed some light or provide conjecture on the implementation? :slight_smile:


(taktik) #2

Yup, that’s basically it.

It’s:

with Drive [0 to 1] and Input [-1 to 1]
Output = pow(abs(Input), 1.0 - Drive * 0.9))
– followed by a auto-DC filter.

The Drive parameter modifies the shape.
The Tone parameter controls a shelf filter’s gain at 1200 Hz

See plot on wolframalpha how the drive parameter modifies the shape.


(ffx) #3

Thanks taktik! Any chance you would also share the exact “shape” soft-clipping algorithm?