It might sound like a broad term but the subject producers study as they work on their tracks and look to make mixes sound better could be called "music technology." Funnily enough, often it's the second of those two words we tend to focus on, always looking to improve the technical and technological parts of our productions with new techniques, plug-ins and tricks. With enough patience and care, it's possible to reach the summits of our technological goals, with mixes which burst out of speakers supported by comprehensive control over the tools within our chosen DAW. However, sooner or later, the thing which is likely to hold us back is that we haven't spent enough time learning and continuing our research into the first of those two words: music.

If you build your tracks from loops or preset phrases, studying chords and relationships between notes might not seem so important but, as ever, if your music is to be unique, it'll need to rely on more than just musical extracts put together by someone else. Through this tutorial, we're going to find out that chords, notes and "music theory" need not be a dry subject but instead one which can bring your tracks on in leaps and bounds. By extending the harmonic possibilities of your track, you can open yourself up to a wider range of musical ideas.

Firstly, let's look at notes and how harmony is supported by science and, in fact, the very substance of synthesizers themselves. Harmony means "more than one note playing at once," which is exactly what chords are—two, three, four or more notes playing together. As you'll know, some notes when played together sound musically "right," whereas others can clash or jar as they reach your ear. The reason for this drills into the very fabric of sound and, to understand this, we can actually look at synthesizer oscillators.

"If your music is to be unique, it'll
need to rely on more than just musical
extracts put together by someone else."

These building blocks of a synth sound usually offer a number of wave-shapes and these, in turn, are different combinations of fundamental frequencies and harmonics. Harmonics are overtones or, if you prefer, extra notes which vibrate and sound whenever a fundamental frequency is sounded (on any instrument). The relationship between these notes is based on mathematics—so if you have a fundamental frequency at 100Hz, you'll hear overtones at 200Hz, 300Hz, 400Hz and so on. (For a more detailed explanation about fundamentals, harmonics and so on, read our Subtractive synths explained tutorial.)

So far, we seem to be talking maths but, let's turn this into a more musical explanation. Suppose that note at 100Hz is G (it isn't, but let's not worry about that for now!). The first harmonic comes at 200Hz and as you'll know from the synthesis tutorial, every time a frequency doubles, its octave rises, so this will also be a G. In case you're getting lost, don't worry—all this simply means is that if you play a G on any instrument, science dictates that the G, an octave above will also sound, producing "natural" harmony. However, this harmony won't be very interesting—play a G on your synth and then play the octave higher and while the sound will get louder it won't sound fat or rich yet.

The second harmonic, at 300Hz, would start to make the chord more interesting, as this gives us a D. This note is the "fifth," as it represents the fifth note in the scale, of which more shortly. The following harmonic also provides a G but harmonics four, five and six are the interesting ones, as they provide B, D and F. So, to summarise, every time you play a G, discounting the extra Gs, "science" dictates that D, B and F will also sound "naturally." Take the F out of this chord for a moment and you're left with G, B and D, which happens to be the chord of G major.

You can hear how these natural harmonics open up in the first audio clip, which features a resonant low pass filter applied to a sawtooth wave—as the filter opens, check out the obvious overtones which occur naturally. Remember, these aren't extra notes being added—these are simply the harmonics present in that waveform being "included" as the filter opens.

We can now see that major chords don't just make sense "musically"—the very fabric of the way sound is naturally produced means that these chords exist every time a sound is produced by any musical instrument you can think of. So, let's break a major chord down and have a look at how it's constructed.

Hold down any key on your keyboard and then count up four semi-tones (count "one" on the note immediately above the one you're holding rather than that note itself). That note is called the third of the scale. Holding down the original and the third, then count up three more semitones and hold that note down too. That's the fifth of the scale. Now hold down any other key and repeat that pattern, adding the third and fifth again—every time, a major chord will be formed if you add the fourth and seventh semitones above your starting note.

Which chord you're playing is set by the lowest note, so if the first note you play is a C (before you add the fourth and seventh semitones), you're playing C major. If you started on an F, that'll be F major. You can hear this building here as I've played the root note, then "played up" through the semitones, holding down the fourth and seventh to form a major chord.

Once you've grasped this, switching to minor chords is easy—all you need to do is lower the middle note by one semitone. This time, rather than adding the fourth and seventh semitones above your base (or "root") note, add the third and seventh semitones.

Again, once you've played one minor chord, try out others, simply by holding down a new root note and then counting up semitones to add the third and seventh above. Now, you can play any major or minor chord known to man.

Notes can clash, and chords can clash too. If you want an example, play a C major chord followed by an A major one.

While the result isn't disastrous, it doesn't sound very natural either. So how do we know how to put sequences of chords together which make sense? This is where the notion of scales comes in and which notes "between" the major or minor chords you've started experimenting with make sense in any key. Let's take the major scale first, and let's use C major as an example. The full scale is: C, D, E, F, G, A, B before reaching C at the top again.

Looking at the "gaps" between notes, we can see that from C to D there are two semitone steps, from D to E two more, while the gap between E and F is one semitone. In the major scale, the full list of gaps is 2, 2, 1, 2, 2, 2 and then 1 more to get back to the root note of the scale. Again, this works from any starting point, so once you've practiced playing C major, move to a different note and start again, keeping that number of semitone steps between each note you play. Now, as well as being able to play major and minor chords, you can play a major scale.

The minor scale works the same way but just with different semitone gaps between notes. Again starting with C, the full list of notes is: C, D, E flat, F, G, A flat, B flat before reaching C again. In case you're wondering about "flat" notes, this should help. This scale means that the relationships between the notes of a minor scale are (above your root note) 2, 1, 2, 2, 1, 2 and then 2 more to get back to C, the root again.

Generally, we refer to major scales as sounding "happy," while minor ones are "sad" and you can hear that very clearly as you play up and down these scales and play their chords—there's a brightness to major scales compared to the melancholy of minor ones. However, none of this yet answers why some chords next to each other sound so musically right and others sound wrong and "clashy."

Let's look at the previous example, when I asked you to play C major followed by A major. C major's notes are C, E and G, while A major's are A, C# (sharp) and E. Chords tend to work together when there is a common thread which links the two. The more links, the better. There is one note in common between these chords (the E) but the other two are different.

Try this chord change instead—C major to A minor. This progression makes much more musical sense and there are two reasons for this, the first being that two notes are now shared—C and E exist in both chords.

In that clip, you can see and hear that the C and E continue while the G of the first chord drops out to be replaced by an A for the second half. Also, look again at the list of notes present in the scale of C major—C, D, E, F, G, A, B and C again. In both the chords of C major and A minor, all of these notes are covered as the C chord features C, E and G and the A minor chord covers A, C, and E. In the original chord move—C major to A major—the second chord features a C#, which doesn't feature in the scale of C major, and explains why it sounds weird and out of place.

From this, we can draw some useful musical conclusions and connect some dots. Firstly, decide whether your track is going to be in a major or minor key and then, which particular key you want it to be in. Hypothetically, let's choose to make a track in C major. Which chords can I use which will make musical sense? Well, we now know that any chords which use notes directly taken from the C major scale will sound good, which means I can use: C major (C, E and G), D minor (D, F and A), E minor (E, G and B), F major (F, A and C), G major (G, B and D) and A minor (A, C and E).

Of course, music isn't usually made up of chord progressions which simply move up, step by step, so I don't have to use these chords in this order. Instead, I could play the most used chord progression in pop music history—C major, A minor, F major, G major and this will work beautifully, with notes overlapping where possible, as before.

If I decide I want my track to be in a minor key (like most dance music), let's first remind ourselves of our scale: C, D, E flat, F, G, A flat, B flat and then C again. My chords, using notes from that scale alone would be C minor (C, E flat, G), E flat major (E flat, G, B flat), F minor (F, A flat, C), G minor (G, B flat, D), A flat major (A flat, C, E flat) and B flat major (B flat, D, F). This time, I've programmed a progression of C minor to A flat major to F minor to B flat major.

The first time you hear it, it's played as block chords but the second time I've split the chords up to provide a sequence, simply by chopping the notes into 16ths and cycling round the three notes of the chord until the next one takes over.

In the final clip, I've run the two phrases together and added low-pass filter treatments to both sounds and a kick drum. You can begin to hear how the fabric of the tracks we make are based entirely on chords, whether played in a sustained, pad-like way, or broken up into sequences.

If all of this is new, it might seem mind-bendingly complicated but there's no doubt that if you can unlock these chords and understand the relationships between them, the musical ideas in your tracks will improve. My advice would be to start with just playing chords. Look again at the relationship between the major and minor chords and the note gaps between them, before experimenting with trying a few out in sequence and seeing what sounds right.