Hearing Voices


You don’t get harmony when everybody sings the same note.
– Doug Floyd
CHAPTER AIM: To understand musical key change and hear it working.





Immortal Harmony

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Bach is the most harmonically gifted composer who’s ever lived, the “immortal God of Harmony” as Beethoven described him. His music exudes delight in harmonic exploration and invention.

This gift for harmony that puts Bach at the forefront of the greatest of the composers. And that’s because Harmony really is the engine room for classical music. It’s where the fun really happens.


Sure you need parts and components, and Rhythm and Melody provide plenty of this.

But it’s Harmony that is the power behind the thrust and development. As we shall see in this chapter, it is Harmony that takes us from A to B, and often back to A again. In other words, it is providing the narrative, the story of a piece of music.

Before we get into that, we have to take Harmony from its broadest aspect. And that is with the concept of ‘key‘.




Key Concepts

All music, be it by Bach or by te Beatles, is written in a particular key. You have 12 keys to choose from, each coming from the 12 notes of the ocatve…ok, I’ll get into that elsewhere ( Beethoven 4).

So all music is written in a key. Indeed, Hey Jude, which I cited last chapter, is in F, the same key as our Brandenburg Concerto. Listen to them next to each other and it should be clear. They both clearly start in the same key:

Hey Jude (in F major)  

Brandenburg No 2 (in F major)  



The key we begin in is known as the home key, or the tonic. It is our base, the place we start from, and the place we will finish. And we will feel that harmonic tug in the music, even if we are not conscious of it.

Here is the end and start of our movement, edited together, so you can hear they are in the same key:


So we start and end our piece in F major. But in between, we actually change key some six times. What does that mean?

I think it helps to think of key as operating in music in a similar way to how colour operates in painting. To compare keys and harmonies to pallettes and hues of colour.



Chroma Key

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Think of it like this: musical keys are related to each other in sound, rather like colours are in pictures.

Some keys are more closely related, some more distant.

The illustration on the right demostrates this. Say for example, we are in the key of D major. That means we are closest in musical terms to the keys of G and A major, just as in the illustration the yellow is closest to green and orange.


So if we are composing in the key of D, we are using the equivalent of a yellow pallette. That pallette represents different but related colours we can use, whilst staying in the broad range of the key of D.



In painting terms, we might be using lime-greens, bright-oranges. Colours that feel good, and blend in well, with our main yellow tone.


That kind of harmonic activity – modulation is the technical word – happens constantly. These are more subtle shifts in the harmonic fabric than a total change in key. Like chord changes within a pop song.


But somtimes we encounter more dramatic changes in colour or tone. In music, this is signalled by a change of key.

This is like now using an entirely new pallette. Starting with a different pallette of tones.

Let’s say for example we move from our yellow D major to the key of C. Now we are using a pallette with red colours. And tones that relate closely to that.

Bright-orange, perhaps, but also new purple tones.


Much like this, we can change key within a piece of music. Which acts like an entire re-setting of the harmonic palette. And being aware of when that happens can really help us appreciate the music all the more.




Changing Key 

The easiest way to hear a change of key is to compare different keys directly with each other. Take for example our lovely sweet melody:

 1.19-1.38      Melody 1 


Now listen to a section from later in the piece (3.19), where this melody is repeated. Only this time, the key has changed:

 3.19-3.33      Melody 2  

‘Melody 2’ sounds higher in pitch. This is because the key has changed. Melody 1 is playing in D minor, and Melody 2 in G minor.

Play them close together and you should be able to hear the difference clearly:

 1.19-1.38      Melody 1 

 3.19-3.33      Melody 2  



There is no exact science to changing key, although there’s clearly an art to it! It can happen dramatically, or more gradually. This piece tends to the more gradual approach.

Take our 1st shift into a minor key (minor keys sound ambiguous, dark as opposed to major keys which sound bright and happy). This shift happens somewhere after the first minute into the piece:

 1.15-1.50      Shift to minor  


Now that moment happens somewhere around 0.05 seconds in, I would guess. But we don’t really quite know we are in our new key, D minor, until we land there properly at 0.19, and then again more definatively at 0.28.


So that’s a full-on key change. But as I said earlier there is all sorts of harmonic activity going on all the time, when you look more closely. Modulations.

Take our lovely melodic section of this piece again:

 1.19-1.38      Melody 1  


The actual key here is D minor. But the harmonic pattern is constantly shifting, modulating.

This happens constantly in the music, almost every second – seven times in the first nine seconds of this music. If you can’t hear it, here is a clapped version:

 1.19-1.38      Melody 1 Clapped  






I think being aware of these modulations of key, and the way harmonic action drives music along, really helps to appreciate and enjoy classical music. Because so often the action in the music is harmonic.

Let’s look at another section of the music, which comes soon after the ‘melody 1’ section above:

 1.43-2.04     Key Changes  

Now the rhythms of this section are familiar. So are the Melodies. We’ve heard these before in the music, and they are presented here in much the same way as they have been earlier in the music.

It’s the harmonic landscape that is on the move. Those rhythms and those melodies are all pretty constant throughout this section. They repeat. It’s the harmonic language that is really changing, modulating constantly. That is what is driving the music forward, what is telling the story in this music.

These modualtions of key provide an impetus for the music:

 1.43-2.04     Key Changes  


If you’re not sure where the key changes are, here’s a clapped beat to help

 1.43-2.04   Key Changes (clapped) 



Another section, near the end of the movement, where a number of key modulations. How many can you hear?

04.40  Bach Key QUIZ 

There are 7 changes of key in total (8 if you count the one right at the start, in the first second)



Harmonic Action  

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Much of the pleasure of classical music comes through its harmonic versatility, through its bold exploration of the harmonic landscape.

That can prove unnerving at first, particularly if you come from music, like Rock or Pop, that keeps a relatively rigid harmonic structure. In classical music, the harmonic language is changing, modulating, constantly, and that provides so much of the aural fun. But it can be disorientating at first approach.


Harmonic exploration provides us with ear candy, but it also provides structure for a composer. By exploring harmonic relationships, a composer can do two very important things at the same time.


Brandenburg No.6


Firstly, he can give the music a propulsion, a thrust. This is all about change and development. Moving from key to key is a forward dynamic process, and this really is fundamental to classical music. Modulate key and the music throbs and moves. Change key, and you give new life and zest to a piece of music.


Secondly is an opposite but crucial benefit.  Any exploration of key lends the music automatically an opposite motion, towards the end of the story and rest. We begin in a certain key, so as we explore different keys, so we can return home safely back into our home key.


I’m always amazed how powerful this effect is on us, how that power can still operate deep on our unconscious. You don’t have to understand anything about key or harmonic pitch to know, to feel instinctively in a piece of music, when we get closer to our starting key. We have a gravitational tug our home key, and that really provides so much of the narrative drive of classical music.


This movement is a perfect example.

The movement begins in the key of F, and though it takes a number of walks around closely-related keys, a C and a Bb for example. We’ll get into proper detail later in the course Bach 7). For now, suffice it to say we begin in F major. And we end in F major. And when we get to that end, we know it feels right, because that F major has been hanging there, deep underneath, the whole time.

It’s there in the title, Brandenburg Concerto No 2 in F major. It’s what you might call the whole story of the movement.


We’re going to explore the nature of harmonics in a lot more detail in the Advanced part of our Bach course. Please remember, ‘Advanced’ doesn’t necessarily mean harder to grasp. Each Advanced section begins with a historical chapter, looking at the times and ideas behind each piece of music. These should all be straightforward.

If you fancy jumping on to the Advanced course, use the orange link below.

Or you can stay on the introductory course by clicking on the blue link below. That will take you to our next composer: the highly delicious Johannes Chrysostomus Wolfgangus Theophilus Mozart.




  • When you get Bach at his harmonic peak, you basically get cathedrals of sound. This is the Sanctus, from Bach’s B minor mass is so rich in harmonic texture. The movement has a wonderful fugue at the end, you can jump straight to that point by clicking here.
  • Check out also his wonderfully energetic Cum Spiritu Santo from the same piece.
  • Equally large looms the Mathew Passion, of which this Erbarme dich, mein Gott (have mercy, my Lord) is rightly one of the most celebrated sections.
  • For harmonic tension, listen to this opening of his St John’s Passion. In the instrumental opening the close proximity of the harmonies (listen closely to the woodwind) give the music a heightened intensity and pain.