A Dictionary of Music and Musicians/Compass
COMPASS, from the Latin compassus, 'a circle,' designates the range of notes of any voice or instrument as lying within the limits of the extreme sounds it is capable of producing.
The compass of the various instruments which are in use in modern music will be found under their respective names; but it may be said generally that it is limited in the direction of the bass, but often varies in the direction of the treble according to the skill of the player, except in instruments of fixed intonation.
The compass of a modern orchestra is generally from about the lowest note of the double basses to about E in altissimo, which can be taken by the violin if properly led up to.
The compass of voices for chorus purposes is from F below the bass stave to A above the treble stave. Solos are not often written above C in alt, except for special singers: as the part of Astrafiammante in Mozart's 'Zauberflöte,' which was written for Josepha Hofer, his sister-in-law, and goes up to F in altissimo. [See Agujari.]
The compass of voices varies much in different climates. In Russia there are said to be basses of extraordinary depth, capable of taking the F an 8ve below the bass stave. Basses are not often heard in England who can go below lower C, which is a fifth above that.[ C. H. H. P. ]