Key Signatures

Key of E major in TwinNote music notation

TwinNote has its own key signatures that convey the same basic information that traditional key signatures do:

  • Which notes are in the key.
  • Whether the “non-natural” notes in the key are sharp or flat.
  • How many sharp or flat notes are in the key. This corresponds to the position of the key on the circle/spiral of 5ths.

TwinNote’s key signatures also (optionally) indicate the following, which is not conveyed by traditional key signatures despite being very useful:

  • The tonic note of the key, which indicates whether the key is major, minor, or modal.

TwinNote’s key signatures are there to help musicians know what to expect. Unlike traditional key signatures, it is not necessary to constantly remember the key signature while playing. A musician could ignore the key signature and still play the correct notes based on their appearance alone (their vertical position on the staff and note head shape).

Reading TwinNote’s Key Signatures

The two vertical bars (one solid and one hollow) concisely indicate which notes are in the key. In the illustrations below, notice how these two vertical bars correspond to the notes in the key — the solid bar indicates the part of the staff with solid triangle notes, and the hollow bar indicates the part of the staff with hollow triangle notes.

Key of A Flat major in TwinNote music notation

To the left or right side of the vertical bars is a small note head that indicates the tonic note in the key. It is located in a different position (relative to the two vertical bars) for keys that are major, minor, or modal. It is optional.[1] The illustration above shows an A flat major key signature, and the one below shows an F minor key signature.

Key of F minor in TwinNote music notation

Any given key may contain either sharp notes or flat notes but not both. Above the two vertical bars is one of TwinNote’s accidental signs that indicates whether the key is a sharp key or a flat key — whether any “non-natural” notes in the key are sharps or flats. It looks like a matchstick pointing either up for sharp or down for flat.

This tells you the names of enharmonically equivalent notes within the current key — notes like the black keys on a piano that have different names but have the same pitch (in 12-tone equal temperament[2]). For example, you see a note that could be a B flat or an A sharp. You already know what note to play based on its appearance on the staff, but what is its name? Lets assume it has no accidental sign so you know it must be a note in the current key. Is the current key a sharp key or a flat key? This will tell you whether the note is an A sharp or a B flat. (If you do not remember it is easy to glance at the key signature.) This is how TwinNote’s key signatures make it possible to use the standard Names of Notes and Intervals.[3]

Next to the accidental sign is a number indicating how many sharps or flats are in the key. This corresponds to the position of the key on the circle/spiral of fifths. In a key with no sharps or flats, like C major or A minor, a natural sign and a zero are shown.

As in traditional notation, TwinNote’s alternative accidental signs do not appear before sharp or flat notes that are in the current key, they only appear before accidental notes.

Key of D phrygian in TwinNote music notation

In the illustration above the position of the tonic note head indicates that the music is not major or minor but modal (in this case Phrygian).

A comprehesive overview of key signatures can be seen in this PDF file. This file and all the illustrations on this page were created using LilyPond.

Next: Accidental Signs

  1. If a composer wants to leave the tonic note unspecified and uncertain (as is the case with traditional key signatures), the tonic indicator note head can simply be omitted from the key signature. Return
  2. This assumes the standard tuning system of 12-tone equal temperament. Of course, in other tuning systems the pitch of “enharmonically equivalent” notes may differ slightly. In that case TwinNote’s accidental signs and key signatures indicate these subtle shifts in pitch/intonation, as well as the different names of the notes. See the Enharmonic Equivalents tutorial on the Music Notation Project’s site. Return
  3. If a musician is using an alternative nomenclature that does not differentiate between sharps and flats, she can ignore or omit the symbols above the staff that indicate that the key is sharp or flat and how many sharps or flats there are. Return