A super-wide mix always makes the song better, right?
Some genres, such as funk or acoustic music sound unnatural if they’re overly wide. What’s more important, though, is having the know-how to make the mix as wide as it needs to be, every time, without having tracks disappear when you listen to it on your phone or tablet speakers.
Note: This article isn’t meant to be an exhaustive resource on stereo imaging. I’ll cover a handful of options you have in each phase of the production process, but I won’t go into massive detail.
“Record like there’s no mixing. Mix like there’s no mastering.” — Unknown
What’s the difference between mono and stereo?
The difference between mono and stereo sound is not simply the number of channels used to record and playback audio. Mono audio is recorded and played back with one channel. A mono signal can be panned anywhere in a stereo field, but the information can be 100% represented by a single track or speaker. Stereo sounds require at least two record and playback channels. The audio on these channels differs slightly from each other, resulting from using two microphones, a stereo effects processor, or two different signal paths, like a miked speaker along with a DI box.
Stereo playback systems allow for sound sources to be localized between two speakers. Mono sounds may be panned to a particular location in the stereo field. The source is considered mono while the stereo playback system presents a panoramic perspective. True stereo sounds create the perception of width, whereas mono sounds do not contain any directional information until they are panned in a stereo playback system.
Stereo monitors trick the brain into perceiving that sound is coming from somewhere between the left and right speakers. For example, when both speakers play the exact same signal, the brain hears the sound as coming from between the speakers, in the center of that stereo field. This position is called a “phantom center” image.
The Sense of Space
The brain uses a combination of timing, level, phase, and tonal differences to figure out the positioning of a sound in space around your head. A sound that occurs on your right side will obviously reach your right ear before reaching your left ear. Furthermore, the phase differences between the ears, along with comb filtering effects and the sense of direct vs reflected sounds inform your brain about where a sound is coming from.
Width (left-right), height (up-down) and depth (front-back) form the 3D space known as a stereo field. These descriptions are sometimes referred to as azimuth, elevation, and distance.
Width is dictated by a difference in the sound between the left and right channels.
Height is a result of the frequency content of a sound in relation to other sounds in the mix. Sounds with predominantly high-frequency content are heard as being above sounds comprised of mostly low frequencies.
Depth is created via a combination of a sound’s level in relation to all the other mix elements, its dynamic range, and its ambience. Quieter, less dynamic, more reverberant sounds are usually perceived as being farther away in the stereo field.
There are many different thoughts about symmetry in a mix. We create one type of symmetry by panning instruments that complement each other to opposite sides of the mix. For instance, a rhythmic guitar part and a rhythmic piano part may be panned hard-left and hard-right to balance each other and also stay out of each other’s way.
Symmetry can also involve frequency balances, as with a mandolin part panned opposite a shaker or a high string pad. Here both the left and right channels contain similar frequency content.
Finally, energy can create symmetry. Pan the rhythm guitar one way and the congas the opposite way so that each channel carries similar percussive energy.
There is no right or wrong, but keep in mind that the sense of space comes from contrast. If everything is wide, nothing will feel wide. Listen to your favorite mixes to see how the producers and mixers chose to pan sounds and how they created a balanced, yet wide soundstage.
Stage 1: Production Tips for a Wide Stereo Image
Decisions in both the production stage and the mixing stage affect the overall stereo image of a mix. This is convenient because, for most artists, production and mixing blend into one another. So, a healthy, wide stereo image starts during the production phase.
Which instruments will be used in your song?
Which frequency ranges do they occupy?
Which instruments will be recorded in stereo or double-tracked during the recording process?
Creating Stereo Width Acoustically
Let’s say you’re working on an acoustic song, consisting of a piano, two acoustic guitars, drumset, and vocal. You may want to create width via the contrast between the two acoustic guitars. Ideally, you’d have the acoustic guitars played by 2 different people, using 2 different guitars, playing 2 different parts. With the drums, bass, and vocals mostly centered, panning the acoustic guitars wide will present a very wide soundstage. The contrast between center and side elements creates space.
This song contains 1 acoustic guitar and a piano on harmony duties in different registers along with bass, drums, and vocals. Balancing the acoustic guitar against the piano will give you a wide stereo image, again contrasting against the center-panned foundation elements.
You may record acoustic guitar or piano in mono or stereo. Recording in stereo provides you the opportunity to spread a sound out for a spacious sound, or pan the two mics together to localize the instrument to one place. You may also choose to discard one of the mics from a stereo recording if it’s not necessary for the final production. Remember that you don’t need to hard-pan every stereo element. Pan some elements tighter or only center-left or center-right.
Creating Stereo Width Though Double-tracking
There are a few more ways to make sure a mix will be wide, and quite a few of them involve you recording multiple layers, or doubles, of a specific rhythm or background part. We typically stack up multiple passes for rhythm guitars, backing vocals, or even string sections. Double-tracking not only adds thickness to a sound, but it also provides additional opportunities for creative panning and stereo imaging effects.
Note: Simply duplicating a track and panning it to the opposite side will not create a double, you’ll simply make that sound louder and center-panned (mono).
Change the Instrument
Not every acoustic guitar or keyboard or horn sounds the same. Each instrument has its own character. If you wish to double-track a part in your arrangement, it may help to change to a new instrument for the double. Choose a second instrument with different sonic qualities from the first.
The same rule applies when it comes to vocals. Adding a second singer for background vocals can add a new depth and dimension to the vocal. Try recording plenty of doubles and harmonies and spread them around the stereo field during the mixing stage.
Vocal panning styles differ for different genres. Pop music producers often record four tracks of each harmony part and pan them alternating left-right, ending up with two low harmonies left and two right; two mid harmony tracks left and two right, etc. Folk music may have only a single track of each harmony with each harmony panned slightly to one side or the other.
Change Guitar Tones/amplifiers/cabinets
Different amplifiers and/or cabinets sound different from each other. If you recorded a guitar part with a dry and dark tone, try doubling it with something brighter and livelier (dare I say add a tiny bit of reverb?)
For a great example of this type of doubling, listen to Arctic Monkeys’ “Do I Wanna Know?“. During the intro, the left side guitar tone has more low-mids and a bit more reverb than the right guitar. The latter is a brighter and drier tone. Wide stereo image! These tones wouldn’t fight each other even if you pan them closer together.
Change Chord Inversions
A chord inversion is simply when the root (bottom note) of a chord is NOT the lowest note in the said chord. Rearranging the order of a stack of notes that forms a chord gives us a few possible voicings of the same chord. This applies to any instrument that plays chords.
Besides adding some harmonic interest to your production, changing inversions make the double different enough that you get a wider stereo field. Width is created because the notes of each track occupy slightly different frequency ranges and contain different harmonics.
Microphones are like instruments: each one sounds different from another.
If you’re recording vocal doubles and backing vocals, use a different microphone, maybe a less full-sounding one. For even more of a difference, use a dynamic microphone if you recorded with a condenser before. Also, change the distance from the singer to the microphone. Some singers will go as far as using a different microphone or recording chain to record their lead and background parts.
Change Microphone Positions
Microphone positioning greatly affects the frequency content of what you record. Moving a microphone left, right, up, or down by 1 inch in front of a speaker or changing the mic’s angle by 45 degrees can drastically alter the tone picked up from the amp. A mic pointed at the cone picks up a brighter tone than a mic near the edge of the speaker.
If you’re forced to double the same guitar sound played by the same person, changing the mic position will help to give you a somewhat wide stereo field. Distance matters, too, so play around!
Stage 2: Mixing Tips for a Wide Stereo Image
The mix will ultimately define the sense of stereo space in a mix. If the stereo space wasn’t created during the production and recording process, now is the time to figure it out!
Create Width by Mixing in Mono
An online debate began raging in the early to mid-2010s amongst the up-and-coming mixing engineers as to whether mixing in mono, for at least part of the mixing process, is still relevant. Those against mixing in mono declare that nobody actually listens to music in mono anymore. They claim that most of the listeners used headphones or earbuds to listen to music…and that’s the extent of it.
Obviously, they were, are, and will be wrong for the foreseeable future.
Can you tell which side of the debate I was on?
My side espouses the benefits of mixing in mono. There are many cases where music is essentially heard in mono. Music played in clubs, cars, busses, malls, and on phone speakers, as well as Bluetooth speakers often effectively plays in mono. If a mix sounds good in mono, you can be sure it will translate well regardless of the playback device and listening environment.
Mixing in mono can be frustrating until you get used to it. Keep at it; it’ll pay dividends further down the road.
Consider mixing in mono for at the least the start of a mix. Instrumental balances and corrective EQ done in mono force you to give each element its own vertical space. Frequency masking becomes obvious and easy to fix when listening in mono. Panning also affects volume, so you can even adjust panning while monitoring in mono. You won’t hear the sounds move, but you will hear the balance change. After you have found basic balances EQ and panning, flip back to stereo…you’ll be amazed at how wide everything sounds.
Still on the Topic of Mono…
Check your mix in mono to ensure that there are no significant imbalances in the mix, nor cancellation of frequencies when the left and right channels are summed together. It’s important to make sure that any spatial effects don’t get lost due to phase cancellation. Chorus, phasers, flangers, doublers, delays, EQ, and even panning effects can all be subject to crumbling when the mix is summed to mono.
It’s easy enough to check the mix for mono compatibility: If your monitor controller has a mono button use it. If not, use a stereo image plugin in your DAW to collapse the mix to mono. Many inexpensive or free plugins are available, including Boz Digital Labs’ Width Knob, Maat Digital’s 2BusControl, and Brainworx bx_solo, among many other options.
There are three major panning areas in the stereo field: hard left, hard right, and center. Many old consoles had no panpot—only buttons to assign a channel to left, right, or center (both L+R). This style of mixing became known as LCR panning. Some of the most famous mixers still treat panning as an all-or-nothing decision, so don’t discard this idea.
The center is where the most important elements are placed. In most mixes, you’ll find that the lead vocal, kick drum, snare drum, bass, and any lead instruments are in the center. Rhythm guitars, keyboards, shakers, and other intermittent elements are often panned towards the sides.
Beware of leaving keyboard/synth patches in stereo. Some synth patches contain distinct left-right sounds, but many mono sounds that have a stereo chorus or delay effect applied to them. Using these fake-stereo tracks in your mix will quickly eat your mixing real-estate, turning it into mush. If too many sounds are synthesized stereo images, there will be no contrast and your mix will start sound mono.
When it comes to drum overheads, I sometimes pan them 75% left and right, leaving the electric guitars to handle the hard left and right. There’s little midrange frequency content in the overheads, whereas the guitars abound in it. It makes sense to tuck the overheads in just a bit to let the guitars shine.
I use this technique on electric guitars almost every time I mix rock music. Some people call it “frequency slotting“. Once again, the stereo effect is achieved by creating a tonal difference between the left and the right channels.
Try this: hard-pan some double-tracked guitar tracks and EQ them to taste. Next, cut 1dB on the left guitar at, say, 2.3kHz, and boost 1db on the right guitar at the same frequency. Then boost 1dB on the left guitar at 1.7kHz and cut 1dB on the right guitar. (The frequencies I mentioned are meant to be an example. Choose the frequencies you’ll cut and boost in such a way as to not have a negative effect on the guitar tone.)
A particularly striking widening effect can be achieved by sending a sound to a mono (this is important!) reverb aux/bus. Following that, pan the dry and wet tracks in opposite directions. A soft reverb level will increase the width rather subtly. For more of an obvious effect, simply bring up the reverb aux. Enjoy the space and width!
A slap delay, when used as an insert on a mono track, can impart a sense of depth that enhances the localization of the sound. Try a delay between 60 and 100 ms with no feedback and only about 5-10% wet.
The Haas (or Precedence) Effect can add a sense of spaciousness to stereo or mono sounds. To widen a mono sound, duplicate the mono track, then pan the original track to one side and the copy to the opposite side. Then, to the duplicate track, insert a delay of between 8 and 30 milliseconds. You could also nudge the duplicate track by the same amount. Starting with a delay of around 8-9ms, you’ll notice the sound spreading out. Anything longer than 25 to 35ms and you may hear the duplicate track as an echo, instead of a stereo effect.
This Haas Effect method isn’t always mono-compatible, so don’t use it on important tracks. Comb filtering will occur if this sound is summed to mono, which may make the track sound…weird. Check your mix in mono and adjust the delay time if you hear unwanted cancellation.
Stage 3: Mastering Tips for a Wide Stereo Image
Big decisions regarding the stereo image have been taken care of by this stage. So if you’re the mastering engineer, you’ll have to work with what you’re handed.
A word of warning before you do any processing meant to widen the stereo image: if you widen the image too much, there’s a possibility that you’ll diminish the song’s groove. More specifically, if you spread the groove elements too far apart, they’ll stop sounding and feeling connected to each other.
You can safely perform subtle stereo imaging effects almost anywhere in the mastering chain, but for extreme stereo image processing, you’ll want to make stereo adjustments before you do additional processing. For masters that need heavy compression, I prefer to apply stereo imaging after the compressor.
Here are a few tips to help you on your journey to a clean, well balanced, and wide stereo field.
While traditional stereo EQ’ing can clear out congested areas of a mix, it is not specifically a widening tool. Some plugins, like those from Brainworx, Izotope, and Nugen allow you to mono-ize the low frequencies. Centering the low frequencies focuses the powerful elements of the mix and lets other elements have more space around the mix. Sometimes a high shelf boost can “open up” a mix and increase the sense of space without adding harshness to the lead vocal.
Mid-Side (M/S) Processing
M/S compression can very easily ruin your production, so make sure you’re confident before attempting this type of processing on important projects.
To use M/S compression so you get a wider stereo image, consider gently compressing the S(ide). Focus on the low-level (quieter) elements of the sound and bring those up to make them more consistent. This way the stereo image will be firmer and it won’t dip quite as much as without M/S compression. But again, this is a very niche application of the plugin, so BE CAREFUL. Alternatively, you could gently compress only the mids to limit the dynamic range and push the lead instruments slightly down into the track. This could effectively bring up the sides and widen a mix.
One of the most invaluable tools when it comes to increasing width during mastering is a mid-side EQ. Gently boosting high frequencies only on the sides can enhance the sense of space in your mix. Be careful not to boost frequencies in the side that could mask lead instruments in the mid.
Another technique is to simply lower the M(id) portion of the signal using an MS encoder-decoder, such as Voxengo’s (free) MSED, Wave’s Center, or UAD’s Precision K-Stereo Ambience plugin. Try lowering the Mid level by 0.1-0.5dB. In most cases, this should be enough to make a noticeable impact on the stereo image.
III. Specialized Imaging Plugins
Many plugins and hardware devices are available to manipulate the stereo field of a master. They are unique and each one could have an entire article about it. Here are a few of the plugins I use and deem to be transparent if used discreetly.
• Waves’ Center lets you shift the balance, the frequency content, as well as the punch of the track from the Mid to the Sides or vice-versa. This last feature is particularly useful when all you want to do is center the punch of the track so your EDM song sounds more consistent in clubs. This is important for club music because music played there is usually in mono.
• iZotope’s Ozone Imager module is legendary. It’s one of the most used plugins by engineers all over the world whenever they deal with stereo imaging issues. You can widen/narrow 1 to 4 different frequency regions and you can stereoize a mono track. iZotope’s processing is nigh-transparent, which makes it a great addition to anyone’s toolbox.
• Softube’s Weiss MM-1 is a mastering maximizer which has the same technology as the famous hardware mastering processor, the Weiss DS1-MK3. The MM-1 gives you 5 choices when it comes to how you want the limiting to affect the sound: transparent, loud, punchy, wide (use this one), and de-ess. The interface is dead-easy to use, the sound is fabulous and the plugin itself is cheap, for what it offers.
• Leapwing Audio’s CenterOne and StageOne are part of a new crop of plugins which lets you increase the width and depth of your mixes with ease. The sound is great, the results are great, and the company’s very friendly. Yay for Leapwing Audio!
• I use Joey Sturgis Tones’ Sidewidener as my main mixing widener tool. I use it on backing vocals, synths, keyboards, guitar busses, even drum room mics when needed. Usually, all I have to do is instantiate the plugin and that’s it. The default settings are doing a great job.
Here’s a short list of other useful stereo processors:
Voxengo MSED (free!)
Airwindows Wider (free!)
iZotope Imager (free!)
Mastering The Mix Animate – Grow module
Don’t Forget About Monitoring
There’s an acoustic process called crossfeed. Sounds coming out of the left speaker bleed a little into our right ear and vice-versa. When using headphones, crossfeed doesn’t exist, so the left and right channels are fully separated and hard-panned elements are only heard on one side of the mix. Headphones present sound between your ears—inside your head, whereas speakers create sound in front of your head.
If you mix on headphones, try a headphone crossfeed plugin, like Goodhertz CanOpener Studio or 112 dB’s Redline Monitor. These plugins, when placed last on your mix or monitor bus, provide a more realistic soundstage for mixing and mastering on headphones. As always, a properly setup monitor or headphone system, including room correction with Sonarworks Reference 4, allows you to make accurate and creative decisions with confidence.
A wide stereo image is everybody’s responsibility, but it’s the mixer that can make or break it.
Always remember that the production needs to serve the song.
A great song hits home even if it’s played on acoustic guitar.
A bad song is still bad, regardless of how much you polish it in the production phase.
Not every song needs to be super wide. In fact, listen to your favorite songs and really focus on what creates a sense of space. You may be surprised how few elements are hard-panned!