What are the best practices for a healthy stereo mix? Some instruments work better at the center of a song, but which ones? In this guide, I’ll walk you through which instruments should stay mono and which can be spread over the stereo field.
What Does Mono Mean (Stereo Width vs Recording)?
When we discuss mono in this article, we are talking about the width of your song’s mix. We are not talking about recording techniques. Mono vs stereo can mean two different things:
- Width, as in panning. How far a sound is pushed to the left or right speaker. We a track is mixed “in mono” in this sense, we mean that it’s at the center of the mix.
- Recording technique. An audio source can be recorded in mono (with one microphone) or in stereo (with two microphones). This is a different topic and isn’t so relevant once you’re at the mixing stage of your song.
In most situations, you will record all of your instruments in mono on a single microphone. Acoustic guitars can be recorded with two microphones, but that’s a discussion for another article.
So this article will use the terms “mono” and “stereo” in relation to the panning (or width) of a music mix.
What Instruments Should Be in Mono?
In general, low frequencies and dominant elements should be mixed at the center of your track, i.e. in mono. This includes: bass, kick drum, lead vocals, and lead guitar solos.
There are exceptions to this rule, but those exceptions are usually stylistic choices. As always, music is an art form so experimentation can and will occur. But before you go panning your kick to one side and the vocals to the other, keep this disclaimer in mind:
The reason we usually put the vocals and low frequencies in the center of a mix is to prevent unbalanced mixes and phase issues.
If there is more musical content panned to one side than the other, then it will create an uneven listening experience. This will sound the most noticeable to people listening to your song with earbuds or headphones.
And a lopsided mix can quickly deter listeners. It gets annoying very quickly when you can hear more of the music in one earbud than the other. No matter how good your song is, an unbalanced mix will drive people away.
If you want to experiment by panning leads and bass to the sides, then you must balance the volume levels out so the stereo mix does not fatigue one ear more than the other.
For example, a lead vocal in the left ear can be offset by a guitar part filling in the frequencies of the right ear.
Phasing is when two wave forms get canceled out by each other because they are peaking at different times. This phase cancellation causes certain frequencies to sound very weak and quiet. They may disappear from the mix altogether.
Panning your low frequency instruments could lead to phase cancellation if, say, your bass is widened with a stereo spread plugin and the opposing sides of the spread have out-of-sync wave shapes. And you won’t hear the issue while mixing in stereo. It will only become obvious when you listen back on a mono speaker (like a phone).
For this reason, it’s important to check your mix in mono mode before exporting.
Should All Drums Be in Mono?
No, the low frequency parts of a standard drum kit should be mixed in mono but other parts can be spread out over the stereo field. The kick drum should be in mono (at the center of the mix) in most situations. The rest of the drums in the kit can vary based on personal preference.
Here are some common panning techniques used for the parts of a drum kit:
- Snare – usually centered in the mix for hip hop and mainstream pop, but works well slightly off-center (either direction), too.
- Hi-hats – slightly panned by 20% or less, usually to the left
- Toms – Often panned harder to the sides than the rest of the kit, with half the toms to the left and the other half to the right (but if you’re really riding a certain tom in a mix, bring it closer to center so you don’t overload one ear)
- Cymbals – Often panned to the sides. For example: when I’m using a ride cymbal and a crash cymbal I’ll usually pan them in opposite directions.
Should Bass Be in Mono?
Yes, bass parts should be mixed in mono; or, rather, the low end frequencies of your bass should at least be in the center of your mix. You can create more depth to your bass by spreading he higher frequencies (above 150-200 Hz) but keeping everything below that dead center.
This can usually be done with a multiband stereo spreading plugin, like:
If you don’t want to fiddle with multiband effects, then I recommend you keep the bass elements at the center of your mix.
What Instruments Should Be in Stereo or Panned?
You can really pan anything that is not low end (below about 150 Hz) or lead vocals. Guitars, synths, additional perc, backup vocals, and ambient pads work well panned.
Just remember to balance the mix: if you push one instrument to the left, you need something to the right with a similar volume level and frequency range.
There are three main ways to pan or “stereo-ize” these instruments in your song:
- Apply a stereo widening plugin, or
- Record two versions of the same part, or
- Add a stereo delay (it won’t actually pan the instrument but it will create a cool stereo echo)
Both options have their place in certain situations. Stereo plugins work fine if you only have one take, but guitar parts will sound bigger and fuller if you manually record the same part twice.
You can expand the stereo width of a synth by duplicating the part onto a second synth and using a slightly different wave.
Many soft synths allow you to increase the number of “voices” in a single oscillator and spread those voices across the stereo field. I use ANA 2 by Sonic Academy and it has that feature. I’ve never used it, but I’m quite sure Massive by NI has a similar feature.
In genres like hip hop and pop, the extra percussion can get busy. You might have tambourines, shakers, bongos, clackers, sticks, etc. filling in the space between the kick and snare. These little extra percussive bits should be moderately panned to the sides so they don’t bury the snare and hats.
As a rule of thumb, low-end parts and lead vocals should stay at the center of your track’s mix. Everything else can be panned or widened to your hearts content. This is just a general guideline, and I’ve heard several songs that break the rule. If you plan to pan, aim to keep your mix balanced.
Here’s the first example of breaking these rules that I could think of:
In this track, the verse vocals are panned left and right. Then the chorus vocals of the second singer are centered. But the panning is balanced and works well.
If you found this article helpful, then here are a few more guides to consider reading: