Mixing: Stereo Width & How To Increase Mix Width

Dimensionality is a sign of a strong mix, and in stereo mixes, width is perhaps the obvious dimension we want to get right. If you're wondering how to not only make your mixes wider but also enhance the entire stereo field between the left and right extremes, you've come to the right place.

In this article, we'll discuss stereo width in greater detail and uncover the strategies worth employing to enhance the perceived width in our mixes.

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What Is Stereo Width In A Mix?

Before getting to the strategies, let's uncover what width is.

Begin with our natural auditory system; the human body (like many other animals) is designed with two ears. Having two ears allows us to localize sound in our environment. Any small differences in timing/phase as a sound wave reaches our ears will allow our brains to localize the sound's direction relative to our location.

A sound wave that reaches the left ear first will naturally be perceived as being to the left, while a sound wave that reaches the right ear first will naturally be perceived as being to the right. The timing differences can be very small and still perceivable, while longer timing differences are generally heard as distinct echoes (40 ms or more, in most cases).

Sound waves that hit both ears at exactly the same time are generally perceived as being neither left nor right but rather directly ahead, above, behind, beneath, etc.

Of course, our auditory systems are much more nuanced than stereo mixes. We can hear sound sources coming from all directions within 3-dimensional space, whereas stereo mixes only approximate such directionality using two distinct channels.

I should mention that this is true so long as the wavelength is shorter than the distance between our ears, where our brains can sufficiently process differences in the waveform phase — this is why low frequencies are practically omnidirectional.

Stereo mixes (and surround sound formats) take advantage of our natural response to directional sound by utilizing multiple channels of audio for playback. In stereo mixes, we have a left and a right channel, which, when played back in an optimal setup, will coincide with our left and right ears. Think of headphones as the easiest way to achieve such playback, where the left driver is right beside the left ear and the right driver is right beside the right ear.

With stereo mixes, then, we can position elements across the stereo panorama, giving them left-to-right directional characteristics upon playback.

Now, when it comes to width, the width of a mix basically comes down to the differences between the left and right channels. It's ultimately about how much directionality we can get within the stereo panorama.

However, we must be careful because making a mix too wide will lead to phase issues during playback, poor mono compatibility, and an overly thin mix, as low frequencies are more susceptible to phase cancellation.

So, a strong sense of width in a mix is really about contrast. It's about having a strong centre image while also having differences between the left and right channels to give directionality to certain tracks within the mix (instruments, vocals and effects).

In fact, we can utilize phase correlation meters to objectively measure the differences between the waveforms of the left and right channels of a stereo mix.

A phase correlation meter's scale spans continuously from -1 to +1 (or from 180º to 0º).

At +1, we have a 100% correlation between the channels (they are exactly the same).

At 0, we have the “widest permissible left/right divergence” or the widest permissible stereo image.

At -1, our left and right channels are completely out of phase and will completely cancel each other out.

So, again, it's not about maximizing the differences between the left and right mix. Rather, in order to get a wide mix, we want sufficient differences between the left and right channels while still retaining a strong centre/mono image.

Contrast is key, and the centre/mono image is just as important as the side information if we want a strong, wide mix.

I have a video on my top 11 strategies for creating width in the mix that you can check out below:

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Enhance The Stereo Width Of The Mix With Contrasting Panning Of Track And Effects

When it comes to positioning mix elements around the stereo panorama, panning is our number one tool.

Pan pots (potentiometers) are the knobs that control the pan position, from left to right, of each individual channel (track, bus, etc.) in the mix session. They can be tangible knobs (in hardware) that we can physically turn to control the panning direction of a track or bus across the stereo spectrum, or they can be virtual (in digital audio workstations, for example).

Analog pan pots, as the name would suggest, are potentiometers. Digital pan pots utilize DSP.

With pan pots, we can change the “directionality” of a track from hard left (having it only in the left channel) through to centre (having it equally represented in the left and right channels) through to hard right (having it only in the right channel) and everywhere in between.

As a mono track is panned off-centre (where it's equally represented in both channels), its left/right mix is altered. All else being equal, a hard-panned track (having information in only one channel) would be roughly 6 dB quieter than if it were in both channels. For this reason, many DAWs have pan laws to make up for the reduction in level as a track is being panned about the stereo spectrum.

As I mentioned, width (like all mix dimensions) is largely about contrast, so in theory, it's critical to have different elements panned to different locations.

For example, we could maximize the differences between the left and right channels by panning everything to one side only. However, that wouldn't give us a wide mix but rather a lopsided, single-channel mix that might as well be mono.

It may also be tempting, theoretically, to pan each track to its own specific direction across the stereo panorama to “fill out” the width of the mix. However, if we want more contrast (and therefore a greater sense of width), it may actually be more appropriate to utilize an LCR (left, centre, right) approach, where, as the name would suggest, we pan our tracks either hard left, to the centre or hard right.

In panning this way (LCR), we can maintain a strong centre image while also having strong differences between the left and right channels due to the tracks that have been hard-panned to either side. This contrast can help to widen the mix while also helping with mono compatibility (a topic for another article).

Contrasting effects can also help with width.

First off, stereo effects like stereo reverb can help to “fill out” the stereo panorama, especially when tracks are panned with the LCR strategy. Stereo effects can also widen the overall presence of mono tracks by processing the audio of the mono track and having some variation of that audio in the stereo spectrum.

Second off, mono effects can be panned around the stereo spectrum to improve the sense of width. Consider the following techniques (I'll use delay and reverb, as these effects give us the strongest sense of dimensionality in the mix):

• Opposite-side delay/reverb: increase the perceived width by having the mono reverb or delay tail of a track panned to one side of the stereo spectrum on the opposite side.
• Same-direction delay/reverb: pinpoint the directionality of a track by dedicating its time-based effect to the same exact direction (helps anchor elements around the stereo panorama, which can help with the overall width of the mix).

Furthermore, we can use entirely different effects in different sections to evoke different acoustic spaces and overall widths in the mix. For example, the reverb used in the chorus could be different and wider than the reverb used in the sections leading up to the chorus.

The key point I want you to take away from this section is that contrast is important for width in the mix. This is true of the tracks themselves and the effects used within the mix. Panning is our primary tool here.

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Enhance The Stereo Width Of The Mix With Automation

With contrast fresh in our minds, let's talk about automation.

One surefire way to enhance the width throughout the mix is to automate the width between different sections.

The most common example of this is to automate the width of the mix so that the chorus sounds wider and bigger than the previous section.

If we can make certain sections sound wider than others, we can make the width of the mix more dynamic and enhance the overall dimensionality experienced by the end listener. This can be done abruptly with sudden automation moves (or arrangement) or gradually with smoother automation drawn out over time.

Consider adding automation to any of the strategies listed in this article. Remember that music is about changing sound over time, and automation is one of our primary tools for achieving change in the mix over time.

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Enhance The Stereo Width Of The Mix With Reverb

Reverb is an audio effect designed primarily to recreate the natural result of reverberation, which happens when sound waves hit the surfaces of an acoustic environment and reflect back to the listener at varying times and amplitudes.

Reverb is a go-to tool for creating a sense of dimensionality in our mixes, and both stereo and mono reverbs can be used to evoke a sense of width.

Without getting into a masterclass on reverb, let's discuss how it helps with width.

Firstly, stereo reverbs help to fill space in the stereo panorama and do a great job of emulating how we hear acoustic reverberation in real acoustic environments. The real-world reflections within an acoustic space will reach our ears from a variety of directions, and so reverb helps recreate this in the mix.

Secondly, mono reverbs, as I touched on previously, can help balance the stereo information and provide a sense of width when set up to the opposite side of the mono tracks they're affecting. Additionally, mono reverbs panned to the same direction (or close to) the tracks they're affecting can help solidify the position(s) of those tracks in the mix, thereby providing more relative contrast between elements in the stereo panorama.

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Enhance The Stereo Width Of The Mix With Delay

As a time-based effect, delay can help enhance the width of the mix, similarly to how reverb does.

Delay, as an effect, can emulate the initial and subsequent reflections of sound within an acoustic space, thereby yielding more stereo information (unless the delay is strictly mono).

Stereo delays are designed with different parameters for the left and right channels, allowing us to dial in the delay time, feedback/repeats/regeneration, decay, and more on a per-channel basis. Having different settings for our two stereo channels will cause differences in the audio signals and, therefore, a sense of width.

Similar to reverb, we can also pan mono delay effects to achieve differences between the left and right channels. Opposite-side delay can widen a specific element (or multiple elements being sent to a common delay effect). In contrast, same-direction delay can solidify an element's position in the stereo panorama, anchoring it in its location across the stereo “width” in the mix.

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Enhance The Stereo Width Of The Mix With The Haas Effect

The Haas effect (also known as the precedence effect) is a binaural psychoacoustic effect that states when two identical or sufficiently similar sounds are heard in fast succession (typically under 40 ms), they will be heard as a single sound. The ear by which the sound arrives first will largely define the perceived direction of this sound.

When used in mixing, the Haas effect is accomplished using a short-timed stereo delay. Slightly delayed sounds are perceived as a single sound, and the perceived direction of the sound is dependent on the perceived location of the first heard sound, nearly regardless of the direction of the second.

So the Haas effect can help us position a track (or group of tracks) to one distinct location while also filling out information in another direction (generally to the opposite side of the stereo panorama).

In using the Haas effect, we maintain directionality and also achieve some level of balance and contrast between the two stereo channels, which can help with the perceived width of the mix.

On a track-by-track level, the Haas effect can easily widen a mono track, giving it a great sense of dimensionality within the greater context of the mix if necessary. The only issue is that the phase differences may cause issues when the mix is summed back to mono (the once-mono track may be thinned out due to the phase differences in the left and right channels caused by the short delay/Haas effect).

There are a few other techniques to widen mono tracks within a mix, which I discuss and demonstrate in the following video:

While any delay unit or plugin that allows for delay times under 40 milliseconds could work, I prefer using the free Haas plugin from Kilohearts for quick and easy Haas effects in my mixes.

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Enhance The Stereo Width Of The Mix With Doubling Effects

Doubling effects, when panned appropriately, will surely widen the sources they process. The technical workings of doubling effects differ from one plugin/unit to the next. However, all effectively duplicate (double) the direct signal one or more times, process the duplicate(s), and mix them together.

By that token, chorus and flanger effects could be considered doublers, and I'll touch on them briefly toward the end of this section.

When it comes to doubler effects, we'll often have several of the following parameters:

• Mix or gain: these controls allow us to mix the direct signal with the duplicated signal(s) to achieve the doubling effect to begin with.
• Panning: these controls allow us to pan the direct and duplicate signal(s) independently in order to widen the audio.
• Delay: these controls allow us to delay the direct and duplicate signal(s) independently in order to cause differences in phase, which are necessary for the doubling effect to work (rather than having two identical copies), which in turn can be used to widen the audio. Delay sections may also have EQ, feedback/repeat, decay and level parameters for further control.
• Detune: these controls allow us to shift the pitch of the direct and duplicate signal(s) independently, causing slight differences between their waveforms, which are necessary for the doubling effect to work (rather than having two identical copies), which in turn can be used to widen the audio.
• Modulation: some doubler effects allow us to modulate the delay and/or pitch of the direct and duplicate signal(s) independently, which adds dynamic movement to the doubler effect as a whole.

So long as we're panning the doubled versions of a track around the stereo panorama, we can use doublers as widening effects for our individual tracks within the mix and the mix as a whole.

My go-to doubler plugin is the aptly named Waves Doubler. It offers up to 4 additional voices along with the direct signal, panning, gain, delay (with feedback), detune, pitch modulation, and much more.

In addition to “doubler” effects, we can also utilize stereo chorus and flanger effects to widen our tracks. These modulation effects effectively work by delaying a signal, mixing the direct and delayed signals together, and modulating the delay time to add movement to the phase differences between the direct and wet signals. This movement causes the effect.

By panning the direct signal and the delayed signal(s), we can achieve stereo chorus and flanger effects, which can also be used to increase the perceived width of a sound within the mix and the mix as a whole.

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Enhance The Stereo Width Of The Mix With Mid-Side Processing

Mid-side (M-S) processing is a different method of processing stereo information than the typical left-right method.

By passing stereo audio (with left and right channels) through a mid-side matrix, we obtain two different channels to work with:

• Mid channel: made up of all the common information between the left and right channels.
• Side channel: made up of all the different information between the left and right channels.

Put differently, the mid information is what will remain fully intact if the mix is ever summed to mono, while the side information is the information that will be cancelled out if the mix is ever summed to mono.

Mid-side processing, in theory, can be applied to any audio effect. In Logic Pro X (my preferred DAW), we have the option to switch between left-right or mid-side processing in the stereo plugins.

Now, when it comes to width, we can use mid-side processing to our full advantage by having independent control over the centre image (mid-channel) and the side information, which is ultimately what makes a mix wide.

At the most basic level, we can widen a mix by enhancing the side information or diminishing the mid information. Conversely, we can narrow a mix by enhancing the mid information or diminishing the side information.

This isn't a masterclass on mid-side processing, but I'll offer the following points to help stir up some ideas on how M-S processing can help with width:

• M-S gain: we can easily increase the width by increasing the gain of the side channel or decreasing the gain of the mid channel.
• M-S EQ: we can boost the width in certain frequency bands by boosting the gain of the side channel at those frequencies and/or cutting the gain of the mid channel at those frequencies.
• M-S compression: we can either push the side channel forward or backward in the mix with different compression parameters to increase or decrease the mix width. Compression is more complicated, so I'll leave it at that.
• M-S saturation: we can enhance the harmonic content and bring the side channel forward with saturation, thereby increasing the perceived width of the mix.

Again, this isn't a masterclass, but I hope those points help you understand how M-S processing can be used to enhance the width of a mix.

We can even modulate the width of a mix over time by automating the parameters of M-S processes.

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Enhance The Stereo Width Of The Mix With Stereo Widening Effects

Stereo-widening effects are perhaps the most obvious tools for altering the sense of width within a mix.

Stereo-widening plugins typically work by adjusting the level of the side information. We just discussed mid-side processing, so this should make sense. The louder the side/difference information, the “wider” the mix.

However, because the side information is based on the out-of-phase information between the left and right channels, pushing stereo widening plugins too far will cause phase issues within the mix. Use your discretion here.

For example, I generally use stereo widening plugins (if I use them at all) to actually reduce the “width” in certain sections and then automate the effect off or at least back to its default position in sections I want to be wider. Of course, I want you to test these tools out for yourself and to make your own decisions.

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Enhance The Stereo Width Of The Mix With Recording Techniques

Before we ever get to mixing, we can achieve stereo width in the way we record our material.

First off, we can record stereo instruments (like many synths and keyboards) in stereo or mono, depending on what we want out of them — remember the importance of contrast; if everything's stereo and wide, then nothing's really wide in the mix.

Second off, we have a multitude of stereo miking techniques which can be used to record wide-sounding audio (once the individual mic channels are panned).

For example, we have coincident and near-coincident pair techniques where microphones are positioned at the same location or close together, respectively. These mics will capture slightly different sound waves, especially if they're pointed in different directions. With panning, we can achieve decent stereo results with these techniques without significant phase issues.

One special coincident mic technique, known as the mid-side miking technique (sound familiar?), utilizes a cardioid pointed at the sound source and a bidirectional/figure-8 mic pointed to the sides. The cardioid mic signal is used as the mid channel (panned to the centre), while the figure-8 mic signal is duplicated, with one copy panned hard-left and the other panned hard-right with its polarity flipped. This technique yields the same mid-side information we discussed earlier.

We also have spaced pair techniques, where two microphones are positioned at a distance from each other but are still tasked with capturing the same source(s). The differences in sound waves captured can yield a very wide image when the appropriate channels are panned to opposite sides of the mix.

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Related Questions

What is depth in a mix, and how do I increase it? Depth refers to the perceived distance between the listener and a sound source (track) of a mix. The mix, as a whole, has a depth dimension dependent on the differences between the furthest and closest elements and the density of elements between such perceived points. The sense of depth can be enhanced in the following ways:

• Contrasting levels and effects
• Reverb
• Delay
• EQing the high-end
• Transient shaping
• Compression
• Recording techniques

What is height in a mix, and how can I increase it? Height refers to the frequency content of a track or mix. The contrast and balance of frequencies within the audible range give us the dimension of height in a mix. The sense of height can be enhanced in the following ways:

1. Contrasting elements
2. Arrangement
3. Filling out the frequency spectrum
4. Reducing frequency masking
5. Automating height between sections