GarageBand Church Organ
The Church Organ instrument is sample based. It emulates a pipe organ.
Volume slider: Sets the overall volume level of the instrument.
Registration pop-up menu: Provides a number of preset registrations. Registrations are combinations of different pipe organ stop (lever) settings that change the tonal character of the sound by enabling or disabling particular pipes. This alters the harmonics that are heard when you play a key.
Bass buttons: You can activate the lower (bass) pipes with these buttons, adding these lower harmonics, which makes your sound richer and fuller.
Note: The bass buttons are not available in all registrations.
Cutoff slider: Allows more (high) or less (low) of the sound through, making it brighter or damping it.
Attack slider: Makes the sound start more slowly or quickly. A fast setting makes it sound like striking a piano key, whereas a slow setting makes it sound like bowing a violin string.
Release slider: Determines the time it takes for notes to fade out after you let go of the keys on your keyboard.