Clefs and Transposition: What Players Actually Read
A clef fixes one pitch and the staff follows. Transposing instruments move it again, so the same written note reaches the audience at different pitches.
Topic
Pitch, notation, intervals and scales — the vocabulary everything else on this site assumes.
Notation is a technology with a history and a set of conventions that are easy to half-learn. These articles cover the parts that everything else depends on: how intervals are counted, how key signatures are ordered and read, what octave numbers mean in notation, software and instrument ranges, and how clefs and transposition change what a player sees on the page.
A clef fixes one pitch and the staff follows. Transposing instruments move it again, so the same written note reaches the audience at different pitches.
Sharps arrive in the order F C G D A E B and flats in reverse. The order is the circle of fifths written out, one signature at a time.
Naming an interval at sight takes two passes: count the staff positions first, then judge what the accidental does to the size.
Middle C is C4 in scientific pitch notation, C3 on some manufacturers' labelling, and MIDI note 60 in every sequencer. The numbering is a convention.