LEARNING MORE ABOUT THE MUSIC WE SING Lesson 2, for March 25 Scales and Just Intonation continued: To determine the key of a piece with a key signature of sharps, consider the final sharp in the signature to be the leading tone. The tonic of the key will then be a half-step higher. For example, in a piece with a key signature of two sharps, the final sharp in the signature is C#. The tonic of the major key is therefore D, and the signature indicates that the piece is in D major. To determine the key of a piece with a key signature of flats, consider the second to last flat in the signature to be the tonic of the major key. For example, in a piece with a key signature of two flats, the second-to-last flat in in the signature is Bb. Thus the signature of two flats indicates that the piece is in Bb, and Bb is the tonic of the major key. A key signature of three sharps has G# as the final sharp. This signature therefore indicates the key of A. A key signature of three flats has Eb as the second-to-last flat. This signature therefore indicates the key of Eb. For every major key there are three major thirds in its scale. From those, you can easily figure out the high notes and the low notes. There are other ways, as well, for determining high and low notes. Just as the major third in just intonation is narrower than the major third on the piano, so is the minor third in just intonation wider than the minor third on the piano. This means that the high and low notes of the minor third are the reverse of the high and low notes of a major third. That is, in a minor third it is the bottom note that is low and the top note that is high. Anytime you have to sing a minor third, be sure to make the top note high. Thus, in the key of C major, where there is a minor third between A and C, be sure that the C is sung high and is not flat. There is also a minor third between E and G. Again, be sure to sing the G high. In both of these cases you would be singing the high note high anyway, since both C and G are the bottom notes of major thirds. In the key of C major there is also a minor third between D and F, but D, as the supertonic of the key of C, is unstable and should not be used to calculate other notes. Another way to determine high and low notes is to look at half-steps. As you know, diatonic half-steps are wide. Thus, when you see a half-step such as F#-G or Eb-D, you know that the upper note is high and the lower note low. Notice that in these two cases, which involve an F# and an Eb, respectively, the note with a sharp in front of it is low and the note with a flat in front of it is high. All of these rules of thumb produce the same result. In a piece with a key signature of three sharps, all three sharps are low notes. They are low because they have sharps in front of them, because they are the top of major thirds, and because they are the bottom of diatonic half-steps in the scale. In a piece with a key signature of three flats, all three flats are high notes. They are high because they have flats in front of them, because they are the bottom of major thirds, and because they are the top of diatonic half-steps in the scale. End of Lesson 2. Click here to continue to Lesson 3, for March 30. Click here to return to the Lesson List.