Record single sources in mono, whether that's a voice, a bass, a guitar amp or a kick drum. Mix and export in stereo, placing those mono tracks across the speakers with the pan control and keeping the kick, snare, bass and lead vocal in the centre.
Use stereo sources where the width is part of the sound, such as pads, reverb, drum overheads and piano. Then press Mono on the master before you finish, because plenty of people will hear your stereo mix through one speaker.
At a glance
| Property | Mono | Stereo |
|---|---|---|
| Channels | One | Two, left and right |
| What the speakers play | The same signal from each | A separate signal for each |
| Placing a sound | One point, wherever you pan it | Anywhere between the speakers, or spread across them |
| Width | None | Made from the differences between left and right |
| On a single speaker | Plays exactly as it was | Loses whatever existed only in the differences |
| Correlation meter | +1 | Usually between 0 and +1 |
| File size | Half | Double |
| Best for | Vocals, bass, kick, snare, guitar amps and most single instruments | Full mixes, pads, reverb, overheads and piano |
What is the difference between mono and stereo?
A mono recording holds one channel of audio, one stream of numbers describing one waveform. Play it through two speakers and both get that same waveform. A stereo recording holds two channels, one meant for the left speaker and one for the right, and they can be as alike or as different as you like.
Two speakers playing a mono signal at equal level don't sound like two separate sources. Your hearing fuses them into one sound that seems to float halfway between the speakers, a position engineers call the phantom centre. Turn one speaker up and the sound slides towards it; that's all a pan control does.
Stereo goes further, because each speaker can play something the other doesn't. A piano recorded with two mics has its low strings louder in one channel and its high strings louder in the other, and a stereo reverb sends slightly different reflections to each side. Those differences are what you hear as width and space. Engineers split a stereo signal into the mid, which is what the channels share, and the side, which is how they differ, and the mid/side lesson covers both in full.
How stereo places sounds
Your ears work out direction from two clues: a sound from the left is a little louder in your left ear and arrives there a fraction of a millisecond sooner. Stereo playback uses the same two clues. A level difference between the speakers moves a sound towards the louder one, and a timing difference moves it towards whichever plays first.
Almost every mix places its parts with level, because a level difference keeps both speakers in step. Timing differences come from stereo mic pairs, from delays and from wideners, and they're where mono trouble begins. The Haas effect vs panning lesson compares the two side by side.
Does a mono track play from both speakers?
Yes. A mono track in a DAW goes through a pan control on its way to a stereo master, and that pan control decides how much of the one signal each speaker gets. Centred, it's equal in both. So a mix made entirely of mono tracks is still a stereo mix, because the panning gives each track its own place.
DAWs handle this differently. In Ableton Live every track is stereo, and a mono file simply plays the same signal on both sides. Logic Pro and Pro Tools let you make a track mono or stereo. Insert a plug-in on a mono track in Logic and you can choose a mono version or one that takes a mono input and gives a stereo output, which is how a mono guitar gets a stereo reverb or chorus. Pro Tools offers multichannel and multi-mono versions of many plug-ins for stereo tracks; multi-mono runs an independent copy on each side.
How loud a centred mono track is compared with a hard-panned one depends on the DAW's pan law. The pan laws lesson goes through the options.
Reading the lab
The lab plays a stereo loop through a short chain: a delay on the right channel, then width, then pan, then the Mono button. Every screen is measured from that chain. The copy and polarity controls are locked here, since they're about phase more than about mono and stereo; the phase lesson uses them.
The goniometer, top left, plots the left channel against the right. Anything identical in both channels draws a vertical line, while a stereo sound makes a cloud that spreads further sideways the wider it is. The correlation meter underneath puts the same thing in one number: +1 for mono, falling towards 0 as the sides become unrelated.
The figure to watch is dB in mono in the Right now panel. It compares the loop summed to mono with the loop in stereo, so 0 dB means mono costs nothing. The wide screen labelled "What mono does to the tone" sends a click through your settings, adds left and right together and draws the frequency response, so any cancellation shows up as a dip with its frequency marked.
The drums are from the Wonky Percussion pack, and the synth loops and the full mix are from Flow. The two acoustic guitars and the vocal are public-domain recordings from Freesound. You can upload your own sound or record eight seconds of it, and it plays through the lab without leaving your device.
What happens when stereo is played in mono?
A single speaker can only play one signal, so a stereo mix has to be folded down first. The device adds the two channels together, usually halving the result so a centred sound keeps its level. That sum is the mid signal again, and the side is thrown away.
What that does to each part depends on how alike its two channels were. The lab measures it on its own loops:
| Loop | What it is | Correlation | Level in mono |
|---|---|---|---|
| Acoustic guitar | A mono recording, the same signal in both channels | +1.00 | 0 dB |
| Chords | A stereo synth part that's close to mono | +0.97 | −0.1 dB |
| Full mix | Drums, bass and chords mixed in stereo | +0.64 | −0.9 dB |
| Drums | A stereo percussion loop | +0.57 | −1.1 dB |
| Lead | A very wide stereo synth | −0.18 | −3.8 dB |
The full mix loses less than a decibel and its tone doesn't change, which is a healthy result. The lead is the one to worry about. With its correlation below zero, the two sides partly cancel when they're added, so it drops further than a part with merely unrelated sides would. In a real mix that means the lead sits further back in mono than in stereo, while everything in the centre stays where you put it.
The mono version reaches anyone listening on a phone with one loudspeaker, a single Bluetooth or smart speaker, or a venue PA run in mono, and everyone who has the mono audio setting switched on in their phone's accessibility options. The mono compatibility lesson covers testing a whole mix for those listeners.
Can you turn mono into stereo?
Not really, since a mono recording holds one signal and there's no second one hidden inside it. What you can do is create differences between the two channels so the sound feels wider, and every way of doing it has a cost in mono.
The simplest is to delay one side by 5 to 30 ms. In stereo the sound spreads out; in mono the delayed copy lands on the original and cuts a comb filter, a row of notches with the first at 1 ÷ (2 × delay). The lab's 12 ms puts it near 42 Hz, with another every 83 Hz, and the guitar also comes out about 4 dB quieter in mono. Chorus, and stereo wideners that work with delays or phase shifts, do something similar, which the stereo wideners vs mid/side lesson tests one by one.
The methods that survive mono best add something new instead of copying the original. A stereo reverb on a mono vocal leaves the dry vocal in the centre and spreads unrelated reflections around it. A second, separately played take of a guitar panned opposite the first gives two different signals, so nothing cancels in a regular pattern. Recording that double is more work than copying and nudging the first take, and it's the version that still sounds right on a phone.
Should you record in mono or stereo?
Record in mono whenever there's one source and one microphone, which covers most sessions: a vocal, a guitar amp, a bass through a DI box, a kick or a snare. A second channel would hold a copy of the first and double the file size for nothing.
Record in stereo when the width belongs to the instrument or the room. A piano is wide by nature, and so is a drum kit heard from the overheads, a choir or a string section. How you place the two mics decides how well the result holds up in mono.
| Setup | How it's placed | Where the width comes from | In mono |
|---|---|---|---|
| XY | Two directional mics with their capsules together, angled about 90° apart | Level differences only | Very safe |
| Mid/side | One mic facing the source and a figure-of-eight mic facing sideways | The side mic, decoded into left and right | Safest, since mono is the front mic alone |
| ORTF | Two cardioids 17 cm apart, angled 110° | Level, plus timing differences up to about 0.5 ms | Mostly fine, with mild combing |
| Spaced pair | Two mics set well apart, often a metre or more | Large timing differences | The most likely to sound hollow |
Mid/side recording goes back to Alan Blumlein's 1931 stereo patent. It's still the choice when mono matters most, because you can set the width afterwards by turning the side mic up or down.
Which parts of a mix should be mono?
Keep the kick, snare, bass and lead vocal mono and in the centre, where they come through identically on every system. Everything under about 100 to 150 Hz belongs there too. Low frequencies carry most of a mix's energy, so cancellation down there costs the most, and your ears can barely tell which direction a deep bass note comes from anyway. Vinyl adds a practical reason: out-of-phase bass makes the cutting stylus move up and down instead of side to side, which is why mastering for vinyl often narrows the low end. The kick and bass lesson covers fitting the two together.
Width belongs on the parts around them: pads, reverb returns, overheads, doubled guitars and backing vocals. Even here, mono sources panned to different places give a wide mix that can't fall apart in mono, because each track is one signal in one place.
If a stereo synth or sample is too wide, turn its width down. A mid/side width control at 0% gives you exactly the mono sum, and anything between 0 and 100% narrows the sound without touching the centre. The stereo width lesson goes further.
Mono vs stereo processing
A plug-in on a mono track processes one signal. On a stereo track it has two to deal with, and some plug-ins treat them as a pair while others treat them as two unrelated channels.
Compressors and limiters are where it shows. A linked stereo compressor measures both sides and turns them down together, so the image stays put. Unlinked, or running as two mono copies, each side reacts on its own: a loud hit panned left turns down the left channel only, and for a moment the whole mix leans right. Bus compressors are normally linked for that reason. An EQ is less of a worry, though a stereo EQ that boosts only one side changes the balance between them.
Effects can change the format of a track. A chorus, a stereo delay or a stereo reverb on a mono track makes its output stereo, and every plug-in after it in the chain is then working on two channels. A mono reverb keeps a part focused in one spot, which often suits a lead vocal, while a stereo one puts it in a room.
Mono and stereo files and samples
A stereo file is exactly twice the size of a mono file at the same sample rate and bit depth. CD-quality audio, 44.1 kHz at 16 bits, takes about 5.3 MB a minute in mono and 10.6 MB in stereo.
Plenty of stereo files are mono in disguise, with the same signal in both channels. The acoustic guitar in the lab is one: it's a stereo file, and its correlation is exactly +1. Kick and snare one-shots often come like this too. A correlation meter or a goniometer tells you straight away, and you can convert a file like that to mono without losing anything if you'd rather save the space.
For finished music, export your master in stereo. Streaming services, video platforms and distributors expect it, and a mono listener's device sums your stereo file on its own. Speech-only podcasts are sometimes published in mono, since a single voice has nothing to put in the second channel.
How to check a stereo mix in mono
- Put a mono switch last on the masterIn Ableton Live, a Utility with Mono switched on does it. In Logic, the Gain plug-in has a Mono button.
- Play the loudest section and switch back and forthThe kick, snare, bass and vocal should keep their level and tone. A wider part dropping back a little is normal.
- Watch the correlation meterIt should spend most of its time between 0 and +1. Logic's MultiMeter has one, and so do plenty of free metering plug-ins.
- Find the part that changesSolo groups of tracks with the mono switch on until you hear which one goes hollow or quiet. Stereo wideners, copied and delayed doubles and spaced mic pairs are the usual causes.
- Narrow it or replace itTurn down the width of that part, take the delay off one side, or record a real double instead.
If a part changes tone in mono, the cause is phase, and the comb filtering lesson explains the notches you're hearing.
Common mistakes
Recording a mono source as stereo
One mic gives one signal. Recording it to a stereo track just stores two identical copies, and any width you want afterwards has to be faked.
Making everything wide
When every track is spread across the speakers, there's no centre left for the vocal and kick to stand in, and the mix sounds vague. A wide part only sounds wide next to parts that are narrow.
Widening the bass
A chorus or widener on a bass line sounds huge in headphones and thins out on a mono speaker, taking the low end of the mix with it. Keep the sub mono and widen only the upper part.
Judging width on headphones alone
On headphones each ear hears one channel only, so very wide parts sound fine and cancellation stays hidden. Check on speakers and in mono before you call the mix finished.
Exporting a mono master to be safe
A mono master throws away the width for every stereo listener to protect the ones on a single speaker, whose device would have summed the stereo file to mono anyway. Export in stereo and make sure the stereo mix sums well.
Train your ears
The quiz under the lab hides the settings and covers the screens, then asks whether the loop will survive mono. Some rounds are only wider or narrower than the original, which mono handles fine, and others have one side delayed or flipped, which it doesn't. Every round is matched in loudness and plays in stereo, so you have to predict the mono version from what you hear between the speakers. The delayed rounds use 0.7 or 1.5 ms, which pulls the sound towards the left speaker and blurs it, while flipped ones sound as if they have no centre at all.
Questions people ask
Is stereo better than mono?
For a finished music mix, yes: two channels let you place parts across the speakers and give them space, which one channel can’t do. For a single source like a voice, a bass DI or a guitar amp, mono is the better choice, since there’s only one signal to record and a second channel adds nothing but file size.
Should I record vocals in mono or stereo?
Mono. One microphone on one singer gives one signal, and it should sit in the centre of the mix. Use a stereo pair only when the room or a group of singers is part of the sound, as with a choir.
Should bass be mono?
The low end should. Keep everything below roughly 100 to 150 Hz in the centre, because that’s where cancellation costs the most and where your ears can barely tell direction anyway. The upper harmonics of a bass synth can be wider, as long as the sub stays mono.
Should I export my song in mono or stereo?
Stereo. Streaming services, video platforms and distributors all expect a stereo master, and mono listeners get a sum of your stereo file automatically. Check the mix in mono before you export, so you know it survives that sum.
Does a mono track play out of both speakers?
Yes. A mono track panned to the centre of a DAW plays equally from both speakers, so it seems to come from a point between them. Pan it and it plays louder from one side, and only a hard pan puts it in one speaker alone.
Why does my mix sound quieter in mono?
Anything that differs between the two channels loses level when they’re added, so the wide parts drop by up to 3 dB while the centre stays put. A small drop like the lab’s 0.9 dB on the full mix is normal. A big one, or a change in tone, means something is out of phase between the sides.