This post is one of a 2-part series of free basic music theory lessons on my blog, musictheoryde-mystified.com. You can see the complete list here. Please feel welcome to make a comment or ask a question.
Note: This lesson looks at how very high and very low notes are written in music notation. When note pitches are written as text, their exact pitch is indicated by octave numbers. For more on text notation and octave numbering, including some examples and exercises, please visit Text Notation: Pitch And Octave Numbering.
Pitch Ranges Of Instruments
The piano keyboard spans over seven octaves, yet the great stave, the treble clef and bass clef combined, only covers about four octaves, even if we use a couple of ledger lines.
Most instruments only read one stave, yet the issue is the same. Treble instruments often have an extended range of high notes, well above the top of the treble clef. Many bass instruments have a lower range which extends well below the bottom of the bass clef. (For more on pitch ranges of different instruments, please visit Pitch Ranges).
Sure, it’s possible to use more ledger lines to increase the range, but lots of ledger lines are hard to read and take up a lot of space outside the stave. It looks even scarier when there’s a whole passage of notes with several ledger lines.
Octave Signs
When there are several very high notes on the treble clef, we can write them one octave lower and add an octave sign above the first note, followed by a dotted line which extends over the affected passage. A small bar at the end of the dotted line indicates the end of the octave sign.
For very low notes on the bass clef, we write the passage one octave higher. The octave sign, dotted line and bar appear below the affected notes.
Note:
- The exact point at which you start and finish an octave sign is up to the writer: it’s okay to have some notes with a couple of ledger lines.
- Octave signs can start and finish anywhere in a bar.
- Octave signs are seldom used for a single note. They work best when covering several notes or more.
8va and 8vb extend the range of the great stave from over 4 octaves to over 6; even more when combined with the use of a couple of extra ledger lines.
High Octave, Low Octave
Notice a subtle difference in the two signs: the octave up sign is 8va and the octave down sign is 8vb.
- 8va stands for ottava alta which is Italian for a high octave
- 8vb stands for ottava bassa, meaning a low octave
I think of these as:
- 8va is an octave above what’s written
- 8vb is an octave below what’s written
Alternatively, you can just write 8 in either case.
Need to go even higher or lower? You can use the 2-octave up or 2-octave down sign.
- 15ma means 2 octaves up
- 15mb means 2 octaves down
If you wondering why the sign for 2 octaves is 15 rather than 16, it’s because, when counting intervals between one and two octaves, one letter is counted twice. For more on large interval names, please visit How To Name Intervals Larger Than 1 Octave.
What if we want to write very high notes in the bass clef?
This is less common, as bass instruments tend to have a limited treble range, just as treble instruments tend to have a limited bass range. However, for instruments with an extended range such as synthesisers, both octave signs can be used in either clef.
The great stave is considered as a single stave, so in piano music, 8va is only used on the treble clef and 8vb only on the bass clef.
Clef Changes
Another method of changing the displayed pitch of notes is to temporarily change clefs. Like octave signs, these are best used for passages of several notes or more.
Admittedly, this approach suits keyboard players best, as they are well versed in reading both treble and bass clefs. For readers of a single clef, octave below signs may be preferable.
Changing Clefs
In the bass clef, switch to the treble clef for very high notes. The bass clef stays in effect until the next treble clef. No dotted line is needed.
Like octave signs, clef changes can occur anywhere in a bar.
In the treble clef you can switch to the bass clef for very low notes.
Try These…
The exercises below involve both the treble and bass clef. If you only read one or the other, the illustration at the top of the post may help…
Ledger lines involve careful counting. These exercises are good examples of how octave signs and clef changes make reading easier.
Note: The “answers” supplied at the end of this post are not the only option of where to start and finish the octave signs or clef changes. As stated earlier, this is a subjective choice: a few ledger lines are acceptable in standard music notation.
A) Rewrite the following passages using octave signs
B) Rewrite the following passages using either octave signs or temporary clefs
Answers at the end of this post.
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NEXT LESSON: B8. Time Signatures 2: Compound Time
PART 2 CONTENTS: Basic Music Theory Course Contents
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Answers to Try These…
A
B
