The guitar and bass are unique transposing instruments; both play in concert key. That is, when guitar and bass play the note C, an electronic tuner would register the note C. But the guitar and bass octave transpose; that is, the pitch they read is an octave higher than the sound that comes out of their instruments.
This is a slightly unusual practice. The reason for this makes perfect sense, however, if guitar and bass did not transpose like this, their music would be extremely low on the staff. Most of the notes they played would be many ledger lines below the staff—and you know how annoying it is to read that way.
Guitar and bass raise their notes an octave higher to keep the majority of the notes on the staff for ease of reading.
You could go your whole life never knowing this and never notice. But if you ever have to write a unison line for guitar or bass, you'll know exactly what to do (see FIGURE 14.8).
FIGURE 14.8 Guitar Transpose
There are other instrument transpositions that you haven't learned about here. There are clarinets in A and trumpets in D, and French horns can be in almost any key possible. As long as you realize that the name of the instrument is the note you hear (in concert pitch) when it plays a written C, you will know how to read and understand that instrument.