- Whenever I hear an explanation about what the tonic or root note is, it’s about how it creates some kind of gravitational pull in the music. How does it do that exactly? How does our brain piece together what the tonic is? This concept has always just seemed almost supernatural. How does a tonic magically get established?
- I realize that there isn’t a simple answer to this question, but any insight would help. Thanks!
The answer to this depends on time and place. Western music is different from Indian or east Asian music. Western music from the common practice period and later is different from older music, which made more use of the church modes rather than the major-minor system.
If we're talking about modern western music, then the most common situation is that the music is in the major mode, the melody takes most or all of its notes from the major scale, and our ear automatically detects the scale pattern and figures out what the tonic is. If you hear someone walking down the street and singing or whistling a tune that you haven't heard before, this is most likely how your ear is going to figure out the tonic.
Often this is backed up by two other factors: (1) emphasis of the tonic and other important notes such as the dominant, and (2) harmony, especially V-I cadences.
All of this is just a rule of thumb. A lot of music, even pop music, can be extremely complex in its use of scales and chords. The ear has patterns and conventions that it applies subconsciously, and it's amazingly good at this, even if the listener doesn't know consciously what's going on.
The tonic (or the tonic interval or tonic axis, in some modern music styles) is alike a star, which all other sounds gravitate towards. These relationships are in part acoustic and part psychoacoustic.
Generally, the tonic will be overemphasized over a section or maybe an entire piece, all formal points of stability will be based upon its presence, and you will feel like the music is being guided to reach this note.
Unless a tonic ambiguity was desired by the composer (Debussy is a master on this, by the way), then you can’t assure where’s the tonic, or even if it exists at all.
Dmitri Tymoczko’s book (A Geometry of Music) has a great section about this, and introduces the concept of centricity - which is a formalized way of explaining the tonic note role.
Several tendencies combine to produce the feeling of a tonic. First, the tonic is often the first note of a piece. In the accompanying harmony, notes supporting the tonic occur at phrase endings and the end of the whole piece. The tonic is often the most common the note of a piece but this isn't necessary; sometimes other notes are emphasized, the fifth or third above the tonic (supporting the tonic of course.)
So the melody often hits the tonic or tonic harmony at important points and the harmony moves in a manner to emphasize that note.
In most cases the tonic is established in the first bar by the triad 135, the chain 123, 3321, or an upbeat: 5 8, 358, whereby 1 and 8 are the root tones of the tonic and are stressed notes in the melody.
Melodies beginning with 135 contain the tones of the tonic triad, but there are other tunes turning around the fifth tone, which is also an note of the tonic chord in the 1st. measure of the song: 5566 543 ...
Another example 34 533 3223 426 5 ...
The tonic is established by the root tone, the third and the fifth which assembled build the tonic triad and give to the musician and listener the feeling to be at “home”, if not at the beginning then mostly at the end of a phrase.
Although we can't know for certain, music almost certainly originates with singing or rather chanting.
You can hear what happens by listening to certain Buddhist chants. Someone begins and their voice settles to a steady note. Other people join in and many will use the same note. Others' voices will be too low or too high. It would be a strain to reach the same note. They have to adapt by choosing another note that sounds pleasant with the original.
Because of the anatomy of the mammalian ear, some combinations of sounds are more pleasant than others. These are called the natural harmonics. Thus when a crowd of people chant together, they spontaneously tend to form a harmonious chord. (see note)
In fact this phenomenon can be heard even with wolves. Listen to thisYou will hear that the answering wolf sings almost exactly the same initial note as the first. As the song goes on, various harmonies and even melodic fragments appear.
A human singer who wanders away from the chord of a chant will sound off-key. Now, it is possible to move from one note of the chord to another and this provides interest. However it is also possible to move to a note that is close to a natural harmonic (but not too close). This creates a sensation of "wrongness" and therefore tension in the listener. However if the singer moves back to the natural harmony we have a sense of relief. This is called "resolution".
Through the history of music, the human ear has become accustomed to further and further deviations from natural harmony but the ear always craves a return.
As an example, Beethoven was criticised during his lifetime of creating music that was too discordant to listen to, yet today, his harmonies sound perfectly fine to Western ears.
Here you can hear a monk teaching a group of absolute beginners how to perform a chant. First of all they speak the words but, within seconds of them all starting to sing properly, they settle into a chord. EDIT: I've deleted this link because it no longer leads to the correct video.
This is my guess, as an amateur musician who knows some theory:
There are plenty of exceptions, but for modern pop & rock I think it is often a combination of:
- The tonic note often being inferable by its prevalence or the phrasing of the melody
- The way the chords and melody fit together into something we recognize as a scale
Not all the time, but often, the tonic is used often in the melody, or the melody may return to the tonic repeatedly. Or the ends of the musical phrases may form themselves such that they seem to lead to the tonic note. In this way, you can kind of pick up what the tonic is. I would guess this is sort of a special case of:
Picking up on the Scale
If you assume that a melody follows a major scale, then it follows the wholestep/halfstep pattern:
between the notes of the scale, starting with the tonic. Or more traditionally
do re mi fa so la ti do
So, if you hear a single note in a melody, like
E, alone and without context, it could be any note in a 7-note scale:
do re mi fa so la ti do E -- do in the key of E A E -- fa in the key of A F E -- ti in the key of F -- etc
cause you don't have any frame of reference for where you are in the scale. It's like trying to triangulate your position from only one landmark on a map. All you know is that the given note is in the key (again assuming a plain old major scale). But if you hear several notes in a melody, for example
E F# G# A, that forms the pattern
WWH, and there are only two places in the major scale where that pattern occurs. So now you now that either you are in the key of
E or the key of
do re me fa so la ti do E F# G# A A E F# G# A
So, in that example, I'm talking about melody, but obviously the chords have a big role in defining what scale is being played as well. I'd give examples, but that's probably beyond my depth.
Not an Exact Science
With the interplay between the melody and chords how often a "tonic candidate" occurs, there's not always a right answer, as this video makes pretty clear. That video also seems to me like a great example of trying to use chords and melody to figure out the tonic.
And I don't think this mental scale triangulation is a conscious process necessarily or that it even works as perfectly logically as I've described. But my guess is that this is part of what underlies the "establishing of the tonic".
And while my example is of a major scale followed exactly, there are all sorts of examples that go outside that particular box but still sound normal to people--that people are able to derive a tonic from.
Finally, this is just my guesses, but it wouldn't surprise me if someone has done a study about just this sort of thing, playing different melody or chord snippets to people and asking them to play the tonic.