Organo pleno
"With full organ": playing on the organ with the plenum of stops.
What it means
Organo pleno (Italian for "with full organ") denotes playing on the organ with the plenum, that is, with the full sound of the group of stops of a division. What is meant is a sound of principals of various pitches and mixtures, often without reeds or solo stops. In scores the direction "organo pleno" or "with full organ" is written above the staff.
Musical use
In baroque organ music the plenum is the brilliant tonal foundation for preludes, toccatas, fugues and chorale settings. The organist can draw the plenum in full or build it up gradually to shape climaxes. A full sound with pedal and couplers produces great power.
Organo pleno should be distinguished from the tutti, which in the orchestra means all the instruments, and from registration with a solo voice, in which a single stop is brought out as the melody.
Performance practice
At organo pleno, draw the suitable stops for a balanced sound and adapt them to the room. Make sure the voices remain audible even in the full sound; in reverberant churches you often play somewhat more calmly and distinctly.