Understanding velocity range in digital instruments
MIDI velocity values span from 0 to 127, but the relationship between that numeric value and how loud a note sounds depends entirely on the curve applied by a synth or sampler. A linear response would be the simplest interpretation, but most instruments use curves that either compress or exaggerate changes in the middle ranges where performers typically play.
Exponential curves mimic how acoustic instruments naturally respond. When a pianist hits a key slightly harder, the volume jump is barely perceptible, but pushing harder at the loud end creates dramatic dynamic range. This nonlinear relationship is why experienced producers often choose exponential curves for realistic expression.
S-curves and performance feel
An S-curve is actually two curves stitched together: the bottom end stays soft (good for quiet playing and articulation) while the top end gets hot (rewarding forceful playing). This shape encourages musicians to play with more dynamics naturally, since both subtle whispers and aggressive attacks get their proper due.
The choice of curve has no musical right answer. Trap producers often prefer straight linear velocity for predictable, punch-forward levels, while orchestral mock-ups demand exponential or S-curves to sound human. Testing all three against your performance style is worth the minutes it takes.