Editing Transposing instrument (section)

== Mechanical and physical considerations ==
Many [[woodwind instrument]]s have one major scale whose execution involves lifting the fingers more or less sequentially from bottom to top. On [[flute]] and [[saxophone]], and in the second register of the [[clarinet]], this scale is notated as a C scale. This is not the case for [[oboe]] (where this scale is D) or [[bassoon]] (where it is F). The note written as C sounds as the note of the instrument's transposition: on an E{{music|flat}} alto saxophone, that note sounds as a concert E{{music|flat}}, while on an A clarinet, that note sounds as a concert A.

[[Brass instruments]], when played with no valves engaged (or, for [[trombone]]s, with the slide all the way in), play a series of notes that form the overtone series based on some fundamental pitch, e.g., the B{{music|flat}} [[trumpet]], when played with no valves engaged, can play the overtones based on B{{music|flat}}. Usually, that pitch is the note that indicates the transposition of the instrument. Trombones are an exception: while tenor and bass trombones are pitched in B{{music|flat}}, and the alto trombone is in E{{music|flat}}, they read at concert pitch. This convention is not followed in British Brass Band music, where tenor trombone is treated as a transposing instrument in B{{music|flat}}. [[French horn]] is treated as a transposing instrument in F even though many horns have two (or even three) different sets of tubing in different keys (the common double horn has tubing in F and B{{Music|flat}}).

In general, for these instruments there is some reason to consider a certain pitch the "home" note of an instrument, and that pitch is usually written as C for that instrument. The concert pitch of that note is what determines how we refer to the transposition of that instrument.