Scales
The major scale can be seen as degrees. If the 1st degree is C, the 5th degree is G. C to G is a perfect 5th, which is an INTERVAL. An interval is the distance between two notes.
Interval
Quick
abbreviation
Example
in C
Number of
Half Steps
Diminished 5ths are the same as Augmented 4ths. DIMINISHED shortens something, and AUGMENTED raises. The Dim 5th is also know as the TRITONE; named for three tones (whole steps)
augmented 4th
One way to calculate an interval is to actually count the half steps, which you could then compare to the chart above.
In the case to the right, QUALITY is decided by having either a C or a C#. C# is further away, which would mean it is the bigger interval. C is closer, so we see it’s a min 6th.
Quality
Number
when you count the NUMBER,
you always count inclusive
An inversion is taking one of the two notes of an interval, and moving it an octave up or down (towards the other note).
Inversions
when inverted, P5 intervals become P4s
and vice versa
Why is it called a Perfect 5th and Perfect 4th? In a time before mathematics could explain such things, musicians noticed that the intervals we call perfect 4th and 5th we’re different from the rest in sound, and they knew this solely by ear. The P5 has the least clash in pitch with the root, making it very stable. And the P4 is simply P5 inverted.
ALL P5 intervals, no matter what pitches, will make a 3/2 ratio. 3/2 is a very simple ratio. As intervals get more dissonant, the ratios get more complicated.
maj becomes min,
2nds becomes 7ths,
3rds become 6ths -
vice versa for all.
Perfect Unison becomes Perfect octave
Dim 5ths stays the exact same.
659.2 hz ≈ 660 hz
440 hz
