Module 1 · Lesson 3 of 5

Timbre: why a flute is not a violin

A flute and a violin can play the same note at the same loudness and still sound nothing alike. The difference is timbre, and timbre is a recipe: which harmonics are there, and how strong.

14 minHeadphones or studio monitorsKiMiA and your keyboard

In this lesson you will

Connect the shape of a wave to its harmonics
Tell harmonic, inharmonic and noisy sounds apart
Describe an instrument by its harmonic recipe

01Timbre is a recipe

Play the same note on a flute, a clarinet and a violin. The pitch is identical, the loudness can be identical, and yet you would never confuse them. What differs is the timbre, the color of the sound.

Most of that color is the recipe of harmonics: which of them are present, and how loud each one is. A synthesizer’s first job is to give you raw recipes to start from. Those are its oscillator waves, and each classic wave has a recipe you can see and hear:

Figure 1.3.1

Four classic waves and their harmonics

KiMiA oscillators · C3 · filter open

Sine

Triangle

Pulse 50% (square)

Saw

Harmonics

Compare them in a row Audio example — listen in the online course

Same pitch, four recipes. The sine has one harmonic. The triangle has only odd harmonics, falling fast (the 3rd is 19 dB down): soft and flute-like. The square (a pulse at 50%) has odd harmonics falling slowly (the 3rd at −9 dB) and none of the even ones: hollow, like a clarinet. The saw has every harmonic (the 2nd at −6 dB, the 3rd at −9 dB): bright and buzzy, like brass and strings.

Learn these four by ear, because every subtractive sound in this course begins with one of them:

Sine: only the fundamental. Pure, round, a little dull: whistles, sub basses, soft flutes.
Triangle: odd harmonics, fading fast. Soft but less plain than a sine: flutes, ocarinas, gentle leads.
Square: odd harmonics, fading slowly. Hollow and woody: clarinets, chiptune, organs.
Saw: every harmonic, each a little quieter. Bright and buzzy: strings, brass, most classic synth sounds.

At the keyboard

You can see the recipe in the shape. Smooth curves mean few harmonics; sharp corners and sudden jumps mean many. The saw’s vertical drop is the sharpest shape here, which is why it is the brightest wave.

02KiMiA’s Harmonic wave

The oscillator menu has a fifth wave, simply called Harmonic. It is a ready-made recipe: a sine with three harmonics mixed in at fixed levels.

Figure 1.3.2

KiMiA’s Harmonic wave: a sine with three harmonics mixed in

Harmonic wave · C3

Waveform · 2 cycles

Harmonics

Audio example — listen in the online course

The fifth wave on KiMiA’s oscillator menu is a recipe of its own: the fundamental, the 2nd harmonic at −10 dB, the 3rd at −15 dB and the 5th at −22 dB. Like pulling out a few organ drawbars, it gives a round, slightly reedy tone.

Choosing a wave is choosing a recipe. Later modules show you how to change the recipe further: filters remove harmonics (Module 5), and FM and wavetables build new ones (Modules 13 and 14).

03Instruments as recipes

Now the same idea with four instrument-like sounds, all built in KiMiA, all playing A4:

Figure 1.3.3

One pitch (A4), four harmonic recipes

KiMiA patches · A4 · 440 Hz

Flute-like · Sine + breath noise

Clarinet-like · Square through a low-pass

Violin-like · Saws through a low-pass

Bell-like · Four inharmonic partials

The same note, four instruments Audio example — listen in the online course

The note is the same in all four: A4. What changes is which harmonics are there and how strong they are. The flute is almost a pure fundamental. The clarinet keeps the odd harmonics. The violin has them all, fading upward. The bell’s partials are not whole-number multiples of the note at all, which is why it sounds metallic rather than “musical”.

The bell is the odd one out. Its partials (the frequencies it vibrates at) are not whole-number multiples of the note. A metal bar or a bell vibrates in shapes that don’t fit neatly into its length, so its partials fall between the harmonics. That is what inharmonic means, and the ear hears it as “metallic”: struck, clangy, beautiful, but with an unclear pitch.

Pro tip

When you want a sound to blend into a chord, keep its partials harmonic. When you want it to cut through and sparkle, a few inharmonic partials (a bell layer, a metallic attack) catch the ear instantly. Electric pianos mix both: a harmonic body with a slightly inharmonic “tine”.

04Noise: sound without pitch

At the far end from the sine wave is noise: a sound that never repeats. Instead of a few harmonics, it contains every frequency at once, in a random mix.

Figure 1.3.4

Noise: every frequency at once

White noiseNoise through KiMiA’s Noise tone

Spectrum

Switch while it plays: same moment, different sound Audio example — listen in the online course

Noise has no pitch: instead of a few harmonics it contains every frequency, at random. White noise spreads its energy evenly; KiMiA’s Noise tone keeps a band of it, which the ear hears as wind or breath. Every flute, voice and drum has some noise in it.

Real instruments are full of noise: the breath in a flute, the scrape of a bow, the hammer’s thump in a piano, the hiss of cymbals. A little noise at the start of a note makes a synth sound more real; a lot of noise makes wind, waves and drums.

05Try it

Learn the four waves by ear. Load 01 · Pure Sine. In Edit›Subtractive, switch Osc 1 between Sine, Tri, Saw and Pulse while you hold a note. Then close your eyes and switch at random: can you name each one?
The Harmonic wave. Choose Harm. Compare it with the sine: which harmonics did it add?
Three instruments. Load 01 · Breath Flute, 01 · Bowed Saw and 01 · Bell Bar in turn and play the same melody on each. Describe each one with a single word.
Find the noise. On the Breath Flute, turn Noise in the Subtractive panel up and down. At what point does it stop sounding like breath?

Your notes · one word for each wave and each instrument

06Check yourself

Q1Which wave contains every harmonic, each a little quieter than the one below?

The saw has all harmonics, the n-th at 1/n of the fundamental. The square and triangle have only the odd ones.

Q2A square wave and a triangle wave both have only odd harmonics. Why does the square sound brighter?

Same harmonics, different strengths: the square’s 3rd harmonic is about 9 dB below the fundamental, the triangle’s about 19 dB.

Q3Why does a bell sound “metallic” rather than like a clear musical note?

Inharmonic partials don’t line up with a harmonic series, so the ear can’t fuse them into one clear pitch and hears a clangy, struck color.

Q4What is noise, in the sense used here?

Noise has no repeating cycle, so it has no pitch. Its energy is spread over all frequencies instead of a few harmonics.