A playable guide11 short chaptersTurn your sound on
Music,from zero.
No music theory needed. We start with one guitar string and ask simple questions. Why do some notes sound good together? Why are there 12 of them? Why does a song feel like it's going somewhere? Every answer is something you can hear.
Sound
What is a sound?
When you pluck a string, it shakes back and forth very fast. Each shake pushes the air next to it. The push travels through the air, like a ripple across a pond, until it reaches your ear.
That's all sound is: air being pushed and pulled. The dots below are air, slowed way down.
220 shakes a second. Around the middle of a guitar.
Shake faster and the note goes higher. Shake slower and it goes lower. That's the only difference between a high note and a low one. (The number is shakes per second, written Hz.)
A note is just a speed. Faster means higher.
Good pairs
Why do some notes sound good together?
Play two notes at once. Some pairs blend nicely. Others sound harsh. It turns out you can see why.
Think of two people walking side by side. If one takes 3 steps every time the other takes 2, their feet keep landing together. That feels steady. If their steps don't match, they keep drifting in and out of time.
Notes work the same way. Drag the ball to change the second note, and watch the shape on the left. When the two notes match up, it settles into a neat, still pattern. When they don't, it becomes a scribble and you can hear a wobble.
3 to 2. The high note shakes 3 times for every 2 of the low one, so they keep landing together.
The dips in the curve are the good-sounding pairs. Each one is a simple match, like 3 shakes to 2, or 2 to 1.
Notes sound good together when their shaking lines up. The simpler the match, the better it sounds.
Octaves
Why can two different notes sound the same?
The simplest match of all is 2 to 1: one note shaking exactly twice as fast as another. Something odd happens. The second note is clearly higher, yet it sounds like the same note.
That's why an adult and a child can sing a song together. They're singing a doubling apart, and it still sounds like one tune. Musicians call this doubling an octave.
Same direction, same note. Every dot on the dashed line is the same note, each one twice as fast as the last.
So notes don't climb in a straight line. They go round in a spiral. Each time around, you meet the same note again, a little higher.
Double the speed and you get the same note, higher. Notes repeat in circles.
Hidden notes
Why does a guitar sound like a guitar?
A plucked string doesn't only shake as one piece. At the same time it also shakes in halves, in thirds, in quarters and more. Each smaller piece shakes faster, making a higher note.
So one pluck plays a whole stack of notes at once. You don't hear them one by one. You hear them as the sound's personality. A flute has only a few. A guitar has lots. That's why they sound different playing the same note.
Tap a piece to switch it on or off. Then hold the note and hear the sound change.
Here's the surprise. Some of those hidden notes, played together, make a happy-sounding chord. It was inside one string all along.
Every note is secretly a stack of notes, and the good-sounding matches are already in it.
Twelve
Why are there 12 notes?
Let's make our own set of notes. Take the good match of 3 to 2 (musicians call it a fifth). Start on any note and keep jumping up by that much. The circle below is one lap of the spiral, so whenever a jump goes past the top, it wraps around.
Press the button and watch where each note lands.
One note. Press the button to jump.
After 5 jumps the notes are nicely spread out. After 7, you have the notes most songs use. After 12, you land almost exactly back where you started. Twelve is where the circle closes.
It misses by a hair, so modern instruments nudge every jump very slightly to close it perfectly. That's why your guitar has 12 frets between a note and the same note higher up.
This is also where the notes get their colours. Notes that sound good together get similar colours. From here on, the page is in colour.
Twelve isn't made up. It's how many jumps it takes to come back around.
Scales
What is a scale?
Using all 12 notes at once would be like painting with every colour in the box. A scale is a smaller set that goes well together.
On this wheel, notes that sound good together sit side by side. So a scale is just a slice of neighbours: 5 for the simple scale used in folk and blues, 7 for most pop songs.
C major. Seven neighbours on the wheel. Every pad fits, so try tapping a few.
Tap the pads, or press Play a random tune. It's hard to hit a wrong note, because every note in the slice fits. Then switch to Minor. Same notes, but a different one feels like home, and the mood turns sad.
A scale is a slice of notes that get along. Change which note feels like home and the mood changes.
Chords
What is a chord?
A chord is a few notes played at once. The most common one uses three notes that match up really well. They're the same three notes that were hiding inside the string.
On the clock below, a chord makes a triangle. Tap any note on the clock to build a chord on it.
C major: C · E · G. Bright and happy. These are the same notes that were hiding inside one string.
Now press Flip. Only one note moves, and only by one small step. The whole feeling changes, from bright and happy (major) to soft and sad (minor).
A chord is a triangle of notes. Nudge one corner and happy becomes sad.
Home
Why does a song feel like it's going somewhere?
In every song, one chord feels like home. The others feel like being out and about. Your ear enjoys the trip, but it always wants to get back home.
Some chords pull toward home harder than others. The G chord has a note sitting just under home, leaning in like a door that's almost shut. Play G and then C, and you hear it click shut.
Tap a box, then pick a chord. Or just press Play. These four chords are behind a huge number of hit songs.
That loop runs through Let It Be, No Woman, No Cry, With or Without You and Don't Stop Believin'. Try the other loops and hear how the story changes. The coloured lines show each note's path, and good chord changes mostly move notes by tiny steps.
A song is a trip away from home and back again.
Rhythm
What is rhythm?
Everything so far has been too fast to count. Rhythm is the slow side of music, the part you tap your foot to.
It works the same way. A steady beat gets split into halves and quarters, and sounds land on them. Tap the squares to make a beat, or pick one.
Move the Swing slider. Straight beats split evenly. Swung beats go long-short, long-short. That one change turns a march into a groove.
Rhythm is patterns lining up too, just slow enough to dance to. So what happens if we speed one up?
The big one
What happens if you speed up a rhythm?
Two drummers. One hits 3 times per round, the other hits 2. It's a simple rhythm you could tap on a table.
Now press Accelerate and keep listening. At about 20 hits a second your ear can't keep up, and it turns into a buzz. Keep going and the buzz turns into two notes playing together. A chord.
3 against 2. Press Play to hear it slowly, or Accelerate to hear what happens when it speeds up.
Nothing changed except the speed. The rhythm and the chord are the same pattern. Slow, you feel it as a beat. Fast, you hear it as notes.
Rhythm and notes are the same thing at different speeds. That's music: patterns that line up.
Your guitar
What does this mean for my guitar?
All of this is built into your guitar. This one is drawn to scale. Tap anywhere on it to play.
Tap a string. The line on top shows how much of the whole string is still shaking.
See how the frets get closer together as you go up? Each fret shortens the string by the same small amount, one of the 12 steps.
Fret 12 is exactly halfway along the string. Half the string shakes twice as fast, so you get the same note, higher. And the dots on your guitar's neck, on frets 3, 5, 7, 9 and 12, sit right on the good-sounding matches from chapter 01.
Try this on a real guitar. Lightly touch a string right above fret 12 without pressing down, and pluck. You'll hear a bell-like chime. That's one of the hidden notes from chapter 03.
You've been playing physics all along.
That's music.
Things shaking in patterns that line up, arranged in time. Everything else is detail.
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