Bitcrushing & Lo-Fi
Reducing bit depth creates stair-step quantization harmonics. Reducing sample rate creates aliasing. Both create predictable new frequencies from destruction.
Bit Depth
A digital signal stores amplitude as a number. Fewer bits means fewer possible values, and the smooth wave becomes stair-steps. 16-bit gives 65,536 levels (CD quality). 8-bit gives 256 levels (retro game consoles). 1-bit gives just 2 levels, so the signal becomes a pure square wave regardless of the input.
Sample Rate
Fewer samples per second means a lower Nyquist frequency, the highest frequency the system can represent. Frequencies above the Nyquist fold back down as aliasing, creating inharmonic artifacts. This is Part 17's theory made audible.
Predictable Destruction
Unlike random noise, quantization and aliasing create mathematically predictable new harmonics. Bit reduction adds odd harmonics (like a square wave). Sample rate reduction folds frequencies at specific mirror points. Understanding the math lets you use these effects intentionally.
Try it: start at "CD Quality" and lower the bit depth to hear the stair-steps appear. Watch the spectrum fill with new harmonics. At 1-bit, the saw wave becomes a square wave.