Diminished second, 0 half step
Minor second, 1 half step
Major second, 2 half steps or one whole step
Augmented second, 3 half steps or 1 1/2 whole steps
Seconds are probably the easiest intervals to identify. Yet, it is very important to master the identification of seconds since to be able to identify other intervals.
To identify the quality of a second we must know:
- the number of half steps contained in each type of seconds
- the order of musical notes (C, C#-Db, D, etc.). We must remember that between all natural notes, with the exception of E-F and B-C, there is a distance of one whole step.
With this in mind, we can count the number of half steps in a second:
Another way of identifying seconds
If both notes are natural, we don't have to count the number of half steps if we remember that only the seconds E-F and B-C are half steps. If there are accidentals, we can use the following method:
- Make all notes natural and determine the quality.
- Add the accidentals and see how the interval is affected.
- Make all notes natural. G-A is a major 2nd (only E-F and B-C are minor).
- Add a sharp to G. The interval is now smaller, it becomes a minor 2nd Add a sharp to A.
- The interval is now larger, it becomes a major 2nd.
Another example: C#-D double sharp:
- Make all notes natural. C-D is a major 2nd (only E-F and B-C are minor).
- Add a sharp to C. The interval is now smaller, it becomes a minor 2nd.
- Add a sharp to D. The interval is now larger, it becomes a major 2nd.
- Add a second sharp to D. The interval is now even larger, it becomes an augmented 2nd.