Velocity is the force with which a note is played, and it’s vitally important in making MIDI performances sound human.
It’s usually mapped to the volume, the harder we play a key, the louder it sounds. But let’s think for a moment, does only the volume change when we play a key harder on an acoustic piano? The answer is no. Most probably the character of the sound will change too, in the same way the pitch of a snare will change if we play a snare harder.
Starting with a simple hi-hat pattern, we make some variations on the velocity. Then in the instrument, in this case is simpler as part of a Drum Rack, we add a filter and mapped the velocity to the cutoff frequency. In the bass channel, I’m going to use the velocity changes from the Melodic Steps (available within the Creative Extensions Ableton’s free pack) to modulate the filter envelope. It’s a good habit and use velocity to give realism to our compositions. It can be mapped almost to any parameter, volume, filter, pitch to add humanism to our songs.