Chapter 2
Intervals describe the relationship between the pitch of two notes.
Before we progress with this section we should explain the term “interval”. You will hear the term interval used consistently in music.
Intervals describe the relationship between the pitch of two notes.
They are the language of music communication.
An interval can be described in different ways. An interval can describe a ratio between two frequencies or as a distance between two pitches.
For scales, intervals are usually described in semitones and tones.
Key Takeaway
A semitone is the smallest interval. It is the distance between any two adjacent note positions as shown in red in the image.
A tone is the combination of two semitones as shown in blue in the image .
Large Intervals
Intervals are the terminology that describe note relationships.
Intervals are the building blocks of chords and chord progressions and are the foundation for constructing harmony.
As we saw earlier, the harmonic series identified the natural relationship between different notes when an object vibrates at different resonant frequencies. Science and basic math provide meaning and structure to natural sound relationships, which are presented in music as intervals.
Intervals are based on the relationship between harmonics produced by a single vibrating string.
Intervals are important in the language of music. It is helpful to understand how intervals evolved and how and why they received their names.
Intervals can be harmonic or melodic.
An interval is a harmonic interval if two notes are played together.
Notes that create harmony are usually based on chords. A chord is where multiple notes are played simultaneously.
An interval is a melodic interval if two notes are played one after the other in a sequence.
Notes played individually form a melody sequence.
Harmony is how one note sounds or reacts when played together with one or several other notes. A chord is the basic element of harmony.
Intervals are a common language shared by musicians and creators. Musicians, songwriters, backup acts and producers mostly communicate using intervals terms. It is the vocabulary of music improvisation. It’s also much more than that: knowing how different intervals are formed and the harmonising quality of an interval separates the good composers from the great.
We will show how large intervals evolved naturally from different harmonics ratios produced by a single vibrating string or by a vibrating column of air. We will examine why, in practice, different intervals create consonance or dissonance.
An interval retains its identity regardless of the frequency range spanned by the interval.
An interval is just a ratio, or a distance that describes a relationship between any two note positions.
Larger intervals are described using a two-element name (eg. Perfect Fifth Interval).
The first element identifies the interval quality, and the second element indicates the span of the interval. The interval quality identifies the status of the interval and the numerical identifier advises the number of scale degree positions spanned by the interval.
We will use the harmonics of the C note frequency to develop the larger intervals.
If you pluck, strum, or bow a string at the very bottom of the string, just above the bridge, you will generate lots of high harmonics, resulting in a twangy and tinny sounding note. If you activate the string in its mid-point, which is the node position of the second harmonic, you will suppress the second harmonic and generate more bass sounding notes.
The position of activation of a string is significant. Activating a string at 1/7 of its length up from the bridge will generally produce the best mix of harmonics and suppress the dissonant seventh harmonic.
Some of the greatest stringed instrument players and many legend guitars players favour picking or strumming areas on their instruments for some compositions to emphasise higher or lower harmonics which gives the composition a unique sound.
Remember, there are no rules, just suggestions. For stringed instrument players, just experiment playing within different areas of the instrument. Find the areas that give the best sounds for your creations.
Side Note: Where are the 7th, 11th and 14th Harmonics?
Important Note for all especially fretted instrument players: The tables where we show the harmonic series of frequencies and their corresponding notes do not show the seventh harmonic or the fourteenth harmonic (this is the octave above the seventh harmonic). We also do not show the eleventh harmonic.
The seventh harmonic is dissonant, and it would be very beneficial if this harmonic could be suppressed. The reason that this seventh harmonic is dissonant is not that the frequency defined by the harmonic series is dissonant. It is solely down to a tuning system that was internationally accepted for keyed and fretted instruments. The seventh and eleventh harmonics would not be dissonant if played on non-fretted string instruments or on some wind instruments.