Intervals

New blog, fresh new posts and this is my first about music. I was looking some old stuff I wrote when I was on my early 20s – at that time I was really engaged with my music studies – and I think in this first post it would be good to write about one of the most fundamental elements in music : Intervals.

As the only instrument I play is the electric / acoustic guitar, I will have the tendency to use this instrument for some examples, but I believe this post can be used by any kind of instrument.

When we are talking about intervals we are always considering two notes. When we play one note (any) followed by a second note, we get a characteristic sound. This sound results from the difference between these two notes. That difference can be measured. Like we can measure distance in meters or feet, in music the measurement unit is called Interval.

The minimum distance between two notes is half a tone. In the guitar half tone is represented by one fret. Two frets are equivalent to one whole tone. So if we take the note C, play it followed by E, for instance, what we get is a ascending distance of two whole tones and a descending distance of four tones.

However the intervals are not named as “2 and a half tone interval”, “three whole tone interval” and so on. More important than know “how far” is one note from the other is to know how does it sound!
Lets talk about sensation, feeling. If we play the notes C followed by E we have a characteristic sound. If we play D followed by F#, we get the same interval and the same sound, I mean, the same feeling, the only difference is that it will have a slightly higher register.

Let’s give name to our intervals now. Every Interval (forget the distance and keep in mind the sound they produce) has a “name” and that name represents a typical sound, independently of the key we are playing. To know the interval we will always use the first note as the reference. Also the first note is considered to “calculate” the interval. Once again taking as example the notes C and E, the interval they produce is major third – if we start counting whole tones from C to E we get: C – D – E, three notes.

The interval between D and F#: D –E – F#: 3 notes, major third. Now the interval between E and G we get: From E to F# one whole tone but from F# to G half tone. In this case we still have an interval of third, but minor third. Between the notes G and A we have on tone, this characterizes the interval of major second.

There’s a table that can help memorizing then. But again one very important thing about intervals, is the sound of each one. We can find “relaxing intervals” like Perfect fifth, Perfect fourth (try to play the sequence C – G (5^th) – C – F (4^th) – C – E (3^th). Sad intervals like Minor sixth: try the sequence C – G# (minor 6^th) – C – G (5^th). And also more tense intervals like Augmented Fourth (C – F#).

Before finish I just want to point out that this material doesn't follow music theory in all of its formalities. It also may be a bit imprecise in some definitions, so consider it just as a start point.