This Ableton tutorial walks through the bit reduction section of Redux, covering the three controls that shape how digital degradation sounds: bit depth, Shape, and DC Shift.
Lowering the bit depth simulates analog-to-digital conversion at increasingly low resolutions. High values introduce subtle, crispy distortion, while pushing further strips away definition and pushes the sound into aggressive, noisy territory.
The Shape dial changes the bit reduction curve from linear to logarithmic, emulating a quirk found in certain early samplers. The shift in curve behavior produces a noticeably different distortion character, giving you a second dimension of tonal control beyond just the depth setting. DC Shift adds a third variable, further coloring the resulting distortion in ways that interact with both other controls.