# Sound in ten ideas

You can play or sing without ever thinking about what sound is: the instrument and the room take care of it. In a studio you are the instrument, the room and the engineer at once, so a few decisions that used to be made for you become yours. These ten ideas are all you need to make them. None of them is physics, and each comes with something to hear.

Read them in order once. After that, every control in Flesance that touches one of these ideas links back to it.

## Pitch is frequency {#pitch}

A sound is air moving back and forth. How many times a second it does so is its **frequency**, counted in **hertz (Hz)**, and we hear frequency as pitch: slow is low, fast is high. Going up an octave doubles the number, so the A below middle C is 220 Hz, the one above it 440 Hz, and the next 880 Hz. Hearing runs from about 20 Hz, a rumble you feel more than hear, to about 20,000 Hz (20 kHz), the faintest hiss.

<AudioSet title="The same note in three octaves" :examples="[['idea-pitch-low', 'A, 110 Hz'], ['idea-pitch-middle', 'A, 220 Hz'], ['idea-pitch-high', 'A, 440 Hz']]" />

Where you meet this in Flesance: the piano keys of the [note editor](/manual/note-editor#add-note) are pitches, and every control marked in Hz, such as the [frequency of an EQ band](/manual/equaliser#eq-frequency), is a place on this same scale.

## Loudness has a ceiling {#loudness}

Loudness is measured in **decibels (dB)**. In a computer the scale is upside down from what you might expect: 0 dB is the loudest a file can hold, and everything else is a negative number below it. Anything pushed past 0 dB has its top cut off flat, which is called **clipping** and sounds like crackle. The space you leave between your loudest moment and 0 dB is **headroom**, and leaving some costs nothing.

<AudioSet title="Headroom" hint="Both are played at the same loudness, so what you hear is the damage, not the level." :examples="[['idea-headroom-clean', 'With headroom'], ['idea-headroom-clipped', 'Pushed past the ceiling']]" />

Where you meet this in Flesance: the [master](/manual/mixer#master) meter turns red when the song clips, the [volume](/manual/mixer#volume) faders are marked in dB, and the [Limiter](/manual/limiter) is the device that makes a song louder without clipping.

## Timbre is the shape of the wave {#timbre}

Two instruments playing the same note at the same loudness still sound different. That difference is **timbre**, the colour of a sound, and it comes from the shape of the back-and-forth movement. A smooth, round wave sounds pure and soft; a wave with sharp corners sounds bright and buzzy.

<AudioSet title="One phrase, four wave shapes" :examples="[['waveform-sine', 'Sine: round'], ['waveform-triangle', 'Triangle: soft'], ['waveform-square', 'Square: hollow'], ['waveform-saw', 'Saw: bright']]" />

Where you meet this in Flesance: the [waveform](/manual/instruments#waveform) of the synth chooses the shape, and [Drive](/manual/drive) bends a wave to make it brighter and rougher.

## A note is many notes {#harmonics}

Almost every sound is a stack of pure tones: the pitch you name, called the fundamental, and quieter ones above it at two, three, four times its frequency, called **harmonics** or overtones. A flute has few, a saw wave has all of them, and that mixture is what timbre is made of. This is why turning up "the highs" of a bass makes it brighter without making it higher: you are turning up its harmonics, not its pitch.

<AudioSet title="Harmonics" hint="In the third example a filter opens slowly, and the overtones of one held note ring out one after another." :examples="[['idea-harmonics-pure', 'One pure tone'], ['idea-harmonics-rich', 'The same note with all its harmonics'], ['idea-harmonics-sweep', 'The harmonics, one by one']]" />

Where you meet this in Flesance: the synth's [cutoff](/manual/instruments#cutoff) removes harmonics from the top down, and an [EQ](/manual/equaliser) turns groups of them up or down.

## A sound has a shape in time {#time}

How a sound begins and ends matters as much as its colour. A drum starts at once and dies quickly; a bowed string swells in and lingers. The beginning is the **attack**, the dying away is the **decay** or **release**. A fast attack sounds percussive and close; a slow one sounds soft and distant.

<AudioSet title="The same chords with a fast and a slow start" :examples="[['attack-short', 'Fast attack'], ['attack-long', 'Slow attack']]" />

<AudioSet title="The same drums, short and long" :examples="[['drums-decay-short', 'Short decay'], ['drums-decay-long', 'Long decay']]" />

Where you meet this in Flesance: the synth's [attack](/manual/instruments#attack) and [release](/manual/instruments#release) set this shape for an instrument, and the attack and release of a [Compressor](/manual/compressor#compressor-attack) or a [Gate](/manual/gate) decide how quickly those devices react to it.

## Two speakers make a stage {#stereo}

With two speakers or headphones, a sound that is equally loud in both seems to come from the middle, and one that is louder on one side seems to come from that side. This placement is **pan**. A sound that differs a little between left and right seems wide; one that is identical in both is **mono**, a point in the centre. Use headphones for these.

<AudioSet title="Two takes of the same chords" :examples="[['idea-stereo-centre', 'Both in the middle'], ['idea-stereo-wide', 'One on each side']]" />

Where you meet this in Flesance: the [pan](/manual/mixer#pan) knob of every track, and [Width](/manual/utility#utility-width) in Utility.

## Echo and reverberation are the room {#space}

A sound in a room reaches you several times: directly, and then bounced off the walls. A single clear repeat is an **echo**. Thousands of repeats too close together to tell apart are **reverberation**, the sound of the room itself. A recording made without either is called **dry**, and it sounds as if it were inside your head; adding a little space puts it somewhere.

<AudioSet title="The same notes, dry, with an echo, and in a hall" :examples="[['idea-space-dry', 'Dry'], ['idea-space-echo', 'Echo'], ['idea-space-reverb', 'Hall']]" />

Where you meet this in Flesance: [Delay](/manual/delay) makes echoes in time with the song, and [Reverb](/manual/reverb) makes rooms.

## Dynamics: the distance between quiet and loud {#dynamics}

The difference between the quietest and loudest moments of a part is its **dynamics**. Too much of it and the quiet notes vanish behind the other instruments while the loud ones jump out. A **compressor** turns down the loud moments automatically, after which the whole part can be turned up: the quiet notes come forward and nothing jumps.

<AudioSet title="A line played unevenly" hint="Both at the same overall loudness: listen for the quiet notes." :examples="[['idea-dynamics-uneven', 'As played'], ['idea-dynamics-even', 'Evened out']]" />

Where you meet this in Flesance: [velocity](/manual/note-editor#velocity) is how hard each note is played, and the [Compressor](/manual/compressor) evens a part out.

## Two sounds can fight for the same place {#masking}

When two instruments are busy in the same range of frequencies, the ear cannot separate them: each hides the other, and the mix sounds muddy even though neither is too loud. The cure is rarely the volume fader. It is giving each its own range, usually by removing from one what the other needs.

<AudioSet title="A bass and a low pad" :examples="[['idea-masking-fight', 'Both in the low range'], ['idea-masking-carved', 'The low end of the pad removed']]" />

Where you meet this in Flesance: the [EQ](/manual/equaliser) is the tool for this, the [Ducker](/manual/ducker) solves the same fight in time instead of in frequency, and [pan](/manual/mixer#pan) separates parts by position.

## Loudness for streaming {#streaming}

Streaming services measure how loud a whole song is, in a unit called **LUFS**, and turn loud songs down so that everything plays at about the same level, around −14 LUFS. So pushing a song as loud as it will go no longer makes it louder for the listener. It only flattens it: the drums lose their punch, and then the service turns the result down anyway.

<AudioSet title="Two masters of one song" hint="These are at their real levels. The third is what a service plays when given the first." :examples="[['idea-streaming-loud', 'Pushed as loud as it will go'], ['idea-streaming-dynamic', 'Left at −14 LUFS'], ['idea-streaming-loud-turned-down', 'The loud one, turned down by the service']]" />

Compare the second and the third: they are equally loud, and the one that was not pushed has more life in it.

Where you meet this in Flesance: [Meters and loudness](/manual/meters#meters-streaming) shows the number, and the [Limiter](/manual/limiter) is where a song's final loudness is set.