Vocal Production
Mono vs. Stereo: How and When to Use Each Track Type
When you add a new track to your DAW session, you’ll have to decide between mono vs. stereo.
But what does each term mean? And what are the main differences? When should you use a mono track and when is stereo the better choice?
In this article I’ll explain everything you need to know about mono vs. stereo—from tracking to the final master.
What is mono?
Mono is single channel audio that offers no information about where a sound is situated relative to the listener.
A mono track reaches both your ears without any difference in what you hear in the left or right side.
A mono track reaches both your ears without any difference in what you hear in the left or right side.
That means that mono has a flat, direct sound without any sense of direction.
Mono was the original format for recorded music because many early playback systems had only a single speaker. That’s why so many classic songs from the early pop era were first mixed in mono.
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Mono only recordings are rare today, but mono tracks still have an important place in music production.
What is stereo?
Stereo is a two channel audio format that delivers different audio information on the left and right sides.
Stereo audio mimics how you hear sound in the real world with your two ears.
Differences in timing, level and timbre give your brain subconscious clues about where a sound is located around you.
This phenomenon is called spatialization and it’s an important part of psychoacoustics.
In music production, your final master will almost always be a stereo file. Choosing the positioning of your sounds with panning is one of the most important jobs in mixing.
When should you use mono tracks?
Mono tracks should make up the bulk of the channels in your mix.
Unless your source has a natural spread of stereo information, recording in mono is your best bet.
You might think that too many mono channels would make your mix sound narrow.
Stereo audio mimics how you hear sound in the real world with your two ears.
But remember that mono tracks can be panned to any location in the stereo field using your DAW’s mixer.
The easiest way to get a wide sounding mix is to spread your mono tracks out in the texture.
That means placing some elements far out on the extreme left and right sides of the stereo field, while keeping others close to the center.
When should you use stereo tracks?
You should use stereo tracks whenever you record something with natural spatial qualities that you want to reproduce in your mix.
I’m talking about the natural stereo images from drum overheads, room microphones, piano or stereo synth patches.
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These stereo sources help establish a sense of realism and dimension in your mix.
The same can be said for aux return channels from your ambience effects like delay and reverb.
All these stereo source types include some information that’s the same between channels and some that’s different.
If a sound has the same intensity in both the left and right channels, you’ll hear it panned dead center in the stereo field.
If the sounds are different in level, timbre or timing between the left and right channels, you’ll hear them in position within the stereo track.
Most stereo tracks include a mix of mono and stereo information. In fact, it’s unlikely that any stereo tracks will be 100% different between the left and right channels.
Most stereo tracks include a mix of mono and stereo information. In fact, it’s unlikely that any stereo tracks will be 100% different between the left and right channels.
That’s why too many stereo tracks can cause a mix to collapse. The sum of all these channels with lingering mono info converges on the center and makes your mix sound narrow.
Luckily, it’s easy to fix it. Two mono tracks with no common information will never overlap when panned separately—that’s the beauty of recording in mono vs. stereo.
Mixing in mono
Even if massive width is your goal, mono still has a place in your mixing workflow.
With so many different elements in a dense mix, it can be difficult to identify the most serious conflicts.
Adding pan position to the list of variables only makes your job harder.
That’s why many engineers use mixing in mono as part of their process.
By temporarily flattening all the stereo information, you’ll get a clearer picture of how each sound in your mix interacts with the others.
To learn more about how mixing in mono can benefit you, head over to our in-depth guide.
To test your mix in mono, all you have to do is use the mono sum option on your master fader to hear how it sounds.
Mono compatibility
Learn why mixing in mono has its uses. Read - Why Mixing in Mono Is Better for Creating Clarity in Your Mix.
Hearing your mix this way is important for more than just the mono-mixing technique.
In fact, you should test your mix in mono even if you only ever mix with both channels active.
The reason? Compatibility.
Mono compatibility means how well your mix performs when it gets summed to mono.
Mono compatibility means how well your mix performs when it gets summed to mono.
Summing to mono is when the left and right channels add together to create a mono signal. If there’s conflicting information between the two channels, some sounds may cancel each other out.
You might wonder when this problem would ever happen since most playback systems have two stereo speakers.
But the truth is that plenty of stereo listening systems are more mono than they seem.
Any set of speakers where the left and right channels are positioned too close to each other reduce the stereo separation of your mix.
I’m talking about devices like phones, Bluetooth speakers, laptops and most other small speaker systems.
These listening systems have a naturally narrower stereo field with more of the mix prone to overlap.
Make sure to check your mix at least once for mono compatibility before sending it off for mastering.
Our powerful, AI-driven mastering engine listens to your song and delivers pristine, studio-quality music that’s ready for release. Master a track.
- The main root causes of poor mono compatibility are:
- Too many stereo tracks
- Artificial stereo-widening plugins
- Too much reverb or delay
- Phase issues between microphones
Advanced Techniques for Stereo Imaging and Spatialization
While understanding the basic differences between mono and stereo is essential, the use of advanced stereo imaging and spatialization techniques is valuable for music producers.
Mastering these tools can help you create a more engaging, three-dimensional soundstage that captivates your listeners.
Here’s a few advanced stereo imaging and spatialization techniques that can take your mixes to the next level.
Mid/side processing
Learn how to get a wider, 3D sounding mix. Read - Mixing in Stereo: 4 Tips for Wider Sounding Tracks.
One powerful technique for advanced stereo imaging is Mid/Side (M/S) processing.
This method separates the center (mid) information from the side information in a stereo signal, allowing you to process them independently.
For example, you could boost the high frequencies on the sides for a wider-feeling mix, or compress the mid-channel to bring vocals more upfront.
M/S processing can also be used to ensure that your mix is mono-compatible by checking how it sounds with the side information removed.
The Haas effect
Learn about psychoacoustic phenomenons. Read - Psychoacoustics: How Your Brain Affects Your Mix.
Another technique is the Haas effect, also known as the Precedence effect.
This psychoacoustic phenomenon creates a sense of directionality by introducing a small delay (typically under 40 milliseconds) between the left and right channels.
The ear perceives the sound from the first-arriving speaker as the source of the sound, creating a perceived spatial location.
Be careful, though—the Haas effect can cause phase cancellation issues when the mix is summed to mono.
Check out the Haas effect in this video.
Stereo widening
Learn more about stereo widening. Read - Stereo Widening: 7 Simple Ways to Give Your Mix Width.
Stereo widening tools can be useful, but it’s important to use them sparingly to avoid an unnatural, over-processed sound. Too much widening can also cause issues with mono compatibility. A safer method for achieving a wide mix is to make thoughtful use of panning and level differences between the left and right channels, combined with strategic use of reverb and delay.
Lastly, don’t forget about the power of reverb and delay for creating a sense of space. These effects can be used to position elements front-to-back in your mix, enhancing the three-dimensionality of your stereo field.
Moving in stereo
Mono and stereo tracks are basic building blocks in your DAW session.
Knowing which to use is important for the best results.
If you’ve made it through this article you’ll have a solid foundation in the basics of mono vs. stereo.
Michael Hahn is an engineer and producer at Autoland and member of the swirling indie rock trio Slight.
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