Manual (music)

Music written to be played only on the manuals (instead of using the pedals) can be designated by manualiter (first attested in 1511, but particularly common in the 17th and 18th centuries).^[1]

Organ manuals vs. piano keyboards[edit]

Despite the superficial resemblance to piano keyboards, organ manuals require a very different style of playing. Organ keys often require less force to depress than piano keys; however, the keys on mechanical instruments can be very heavy (St Sulpice Paris, St Ouen Rouen, St Etienne Caen, etc.). When depressed, an organ key continues to sound its note at the same volume until the organist releases the key, unlike a piano key, whose note gradually fades away as the string vibrations fade away. On the other hand, while the pianist may allow the piano notes to continue to sound for a few moments after lifting their hands from the keys by depressing the sustain pedal, most organs have no corresponding control; the note invariably ceases when the organist releases the key. The exception is some modern electronic instruments and relatively contemporary upgrades to theatre pipe organ consoles, which may have a knee lever which sustains the previous chords or notes. The knee lever enables an organist to hold a chord or note during a fermata or cadence, thus freeing their hands to turn a page in the sheet music, change stops, conduct a choir or orchestra, or shift hands to another manual.


Another difference is that of dynamic control. Unlike the case of piano keys, the force with which the organist depresses the key has no relation to the note's resonance; instead, the organist controls the volume through use of the expression pedals. While the piano note, then, can only decay, the organ note may increase in volume or undergo other dynamic changes. Some modern electronic instruments allow for volume to vary with the force applied to the key and permit the organist to sustain the note and alter both its attack and decay in a variety of ways. For example, Hammond organs often have an expression pedal, which enables the performer to increase or decrease the volume of a note, chord, or passage. All of these variables mean that both the technique of organ playing and the resulting music are quite different from those of the piano. Nevertheless, the trained pianist may play a basic organ repertoire with little difficulty, although more advanced organ music will require specialized training and practice, as the musician has to learn to play on multiple manuals, set stops and other controls while performing, and play the pedal keyboard with the feet.