Octave signs
Five cases to listen to: the same notes once on ledger lines, once with the sign. The sound stays, the picture moves.
A note far above the staff needs ledger lines, and from the third one up nobody counts them while playing. There is a sign for that: 8va above the notes means “one octave higher than printed”, 8vb below means “one octave lower”, 15ma means two octaves at once.
On this page every case stands twice side by side: without the sign on the left, with it on the right. Listen to both and you hear the same note — that is the whole point. What changes is in the picture alone: every head the sign covers moves by exactly seven steps, that is one octave. Both halves are measured here, the pitch from the sound and the position of the heads from the engraved image.
So the sign is not an instruction to the hand but a help for the eye. It changes nothing about the music, only how comfortably it sits on the page.
One octave up: 8va
Four notes high above the staff: without the sign they hang on ledger lines that have to be counted while reading. With 8va the same passage drops into the staff and is taken in at a glance. The keys pressed are identical in both pictures — you hear no difference because there is none.
One octave down: 8vb
The same downwards, here in the bass clef. An 8vb below the notes pushes the picture up by an octave and the ledger lines underneath disappear. Anyone seeing only the right-hand picture still plays the low notes: the sign is right there with them.
Two octaves: 15ma
High up, one octave is no longer enough. Then 15ma appears — not “16ma”, because the steps are counted from bottom to top, and two octaves stacked share a note in the middle. This sign too is only a reading aid: the key played is the same one as on the left.
Where the sign stops
The sign holds exactly as far as its dashed line reaches. Here it stops after the second note — and sure enough only the first two heads move, the last two sit in the same place in both pictures. That is the test of whether an edition has set the end of the sign properly.
The clef with the little eight
The last case works the other way round. The little eight under the treble clef holds not for a stretch but for the whole piece, and it stands on almost every sheet of guitar music: what is written there sounds an octave lower. Both pictures here sound the same — the music on the right simply sits an octave higher on the paper, because the clef brings it back down.
How far the sign reaches
After 8va a dashed line runs on, and at its end there is a small hook pointing down. That is how far the sign holds and not one note further — where the hook stands, you read again exactly as printed. Some editions also write loco there, Italian for “in place”.
Without that hook the passage is ambiguous, and in engraving ambiguous is the same as wrong. That is why the fourth case here has a deliberately short stretch: the sign stops in the middle of the bar, and the last two notes stand precisely where they would stand without it.
What stands next to it
Which clef fixes which line and why there is more than one: Clefs. What an octave actually is and how it sits among the other distances: Intervals.
Music symbols · Intervals · Music notation glossary
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