Multisampling and Velocity Layers

Separate samples per register and velocity keep a keyboard from sounding like a pitch shifter.

Related

VelocityTimbrePiano

The problem

On one piano patch, why does a soft note differ in colour from a hard one, not just in volume?

How it works

On a real instrument, dynamics change the excitation and resonance of the string or air column. A soft piano strike concentrates energy in low partials; a hard strike adds upper partials quickly and brightens the attack. One sample plus a volume envelope cannot do that. Multisampling records separate zones and velocity layers, often four to eight, switched by thresholds and smoothed with level and filter offset. More layers mean smoother switches but more memory and load time. Key zones address transposition's resonance shift; velocity layers address the spectral change of playing style, and neither replaces the other.

Practice and settings

Pianos often use one or two samples per octave and four to eight velocity layers. Strings and winds use fewer, but expression layers still matter. Put switch points where players rarely hold, so a sustained note does not jump mid-breath. Use short crossfades or gentle level compensation between layers, not an obvious filter jump. Test with a slow crescendo from silence to full force.

What to listen for

Hear a crescendo and notice whether the tone changes face at some point. Hear repeated chords and compare partial balance between soft and hard. Hear a chromatic run upward and listen for a note that suddenly turns dull.

Common misconceptions

That velocity layers are just volume steps; that more layers are always more realistic; that key zones can be rounded off freely.

Sources

• Curtis Roads, The Computer Music Tutorial — 多采样与力度分层的概念核对，未抄原文
• The New Grove Dictionary of Music and Musicians, entry Piano — 力度与音色的关系核对，未抄原文

Used for fact-checking only; all prose is original.