The Difference Between Mixing In Mono Vs. Stereo [Part 2]

February 20, 2020

[Editor’s Note: This article is the second in a two-part series by Gary Gray. Catch up on Part 1 here!]

True Stereo

True Stereo means that a recording is recorded with two input sources – such as two microphones, with these microphone being routed to either 

a) A stereo track (with mic 1 and mic 2 separated within the stereo file), or 

b) Two separate mono tracks, panned hard left and hard right. 

You can see the difference between a stereo file containing a mono signal, and a recorded true stereo file, by noticing that the left and right sides of a true stereo file look different. The left and right side of true stereo files look different because the left and right channels within the stereo file have different information on them. When there is different information on the left  and right channel of a stereo file, the result is a perception of space, width and depth. 

For instance, if you record a grand piano with two microphones spaced far enough apart to pick up different parts of the piano (such as one mic on the lower strings and one mic on the higher strings), and if you route the cables of those microphones to two separate inputs on your interface, you will end up with a true stereo recording. If you decided to record those two microphones onto one stereo track in your DAW, it would look like this:

The file above SOUNDS LIKE STEREO. It sounds wider and more spacious than a mono recording (one mic) because of the fact that two different microphones were used to pick up two different aspects of a single source of sound (one mic is picking up mostly the high strings while the other mic is picking up mostly the low strings of the piano). 

Each mic is focused on one area of the piano, but is also picking up a bit of the sound that the other mic is focused on. In other words, the low piano string mic picks up a bit of the high piano strings, and vice versa. Because of the mic positions, the low piano string sound from the mic near the low piano strings (left speaker) will arrive at our ear before the low piano string sound from the mic near the high piano strings (right speaker). 

The opposite is also true: the high piano string sound from the mic near the high piano strings (right speaker) will arrive at our ear before the high piano string sound from the mic near the low piano strings (left speaker). 

While positioned between two speakers, this difference in arrival time to the left and right ear creates the perception of width, depth and space that we perceive. It’s these very slight delays (some less than a millisecond) that the brain decodes as width, depth and space. This comes from a survival trait we possess, allowing us to pinpoint the location of almost any sound in any space in order to avoid tigers, bears, snakes — and more modernly cars, trains and skateboarders.

Note that in nature, the most dangerous elements man faces emit high frequency sounds. Our ability to pinpoint the location of a low frequency sound is not so sharp. This relates back to why mixing the low end in mono tends to keep a mix more focused and less muddy, and why it’s not so vital where you place a subwoofer in a studio – whereas the placement of a pair of studio monitors is much more important.

Getting back to recording in true stereo; if you decide to record each microphone onto a separate mono track, rather than onto one stereo track as above, no problem. During the mixing stage, you simply need to pan one track hard left and the other track hard right — and the result will sound exactly like the true stereo file above. Here is what routing each mic to a mono track in a true stereo configuration looks like:

Notice something interesting here. We are using two MONO tracks to re-create a single stereo track by doing the following:

  1. Recording mic 1 to one mono track.
  2. Recording mic 2 to another mono track.
  3. Hard Panning each track left and right.

Another Myth

“All mono tracks in a mix are to be left in the center of the mix with no panning and do not contribute to the width, space, or depth of the song. Mono tracks are only for kicks, bass, vocals and stuff like that.”


Any mono track can be used for a variety of purposes in a mix. It can, like the example above, be paired up with another mono track to create a virtual stereo track! A mono track can be panned anywhere in the mix – hard left, hard right, and anywhere in between. In fact, panning a mono track, can sometimes create a much more defined and focused picture of the sound you are panning – rather than trying to pan a stereo file (more on that below). 

If you recorded the piano with one microphone, you would be creating a mono recording of that piano. It would be centered and focused, but lacking in width, depth and space:

Even if you later bounce that single mono piano track to a stereo file, as explained above, the piano would sound exactly the same with no change. It would have a mono sound (centered, more narrow) rather than a wide stereo sound, which you can get if you recorded the piano with two microphones, or if you used effects plug-ins and applied what is called pseudo-stereo. 

Pseudo Stereo 

Pseudo Stereo is what most of us commonly create in the box in our home studios. The word Pseudo comes from the Greek word pseudes, meaning “false or lying.” Pseudo Stereo isn’t really false stereo or stereo that is lying, it simply means that it “Sounds like true stereo but isn’t really true stereo.” It hasn’t been created with two input sources, such as two microphones, or two ¼ inch cables coming from a stereo keyboard. In actual practice, Pseudo Stereo can sometimes sound wider, deeper and more spacious than “True Stereo.”

Pseudo Stereo Mixing

Let’s take the mono lead vocal track we spoke about earlier. 

How can we take this sound which is definitely mono, and give it stereo characteristics such as space, depth and width? There are many things we can do to manipulate that mono lead vocal recording and make it sound like “True Stereo.”

We can duplicate the lead vocal, pan the original hard left, pan the duplicated track hard right, add several milliseconds of delay to one of the tracks and voila! You will hear stereo characteristics with that lead vocal.  Add or subtract milliseconds of delay and the depth, width, color, tone and space will change right before your ears. 

Here we see the basic fundamental of stereo sound at play: two sound sources that are different from one another in some way, routed to separate speakers. 

We could also use send-return routing with a mono track to create pseudo stereo effects. This is like putting a Y fitting on the vocal track, with the mono output going, as normal to the speakers, and another going to a STEREO Aux or Effects track, on which we can place stereo plug-ins, such as reverb and delay, and create STEREO EFFECTS from a MONO sound source – giving that mono sound source space, width and depth. 

Binaural Recording 

With Binaural Recording, sometimes referred to as 3D Binaural Recording, you are basically capturing sound very much like a human would hear it – through two ears – in this case, two microphones acting as ears, affixed to someone’s head or to a mannequin head, or an object resembling a human head. 

This technique is not used very often when mixing music, though I am currently researching this technique for various applications, such as acoustic guitars, choirs, drums, etc. 

If you are interested in sound design and/or foley work (sound effects) for film soundtracks, Binaural Recording is an important tool to know and use. 

One recent innovator in bringing Binaural Recording technology to the masses is a company called Hooke Audio, which has released a set of headphones called the Hooke Verse 3D Binaural Headphones. There are two microphones on the outside of the headphone speakers facing outwards. The result of recording with this set-up is beyond True Stereo, it really sounds like 3D True Stereo; and listening to the playback can be quite astonishing. For instance, during playback, you can hear the scissors of a hairstylist move around your head and almost feel the scissors and comb touching your scalp! 

Now that we know the basics of what mono and stereo files are and how they can be utilized in a mix, there is a need to discuss customized DAW parameters and features.

Customized DAW Parameters and Features

Mixing mono and stereo files requires a thorough knowledge of your particular DAW. For instance, Ableton Live uses ONLY stereo files. When panning with Ableton Live (up to Ableton Live 9), panning something to the left or right does not create the same result as panning something to the left or right in other DAWS. Panning effectively in Ableton Live 10 requires a thorough knowledge of your manual. Similarly, panning in Logic Pro does not create the exact same result as panning in Pro Tools or Cubase or Studio One. Each has specific specifications and options when it comes to panning. 

To say that the music industry and the music production software industry lack standards is an understatement. However, all of these challenges are easily overcome by those who actually study their DAW manual and who practice and experiment and research. 

You CAN set up each DAW so that they all pan the same way, but again, it requires the discipline of studying, practice, experimentation and research. 

Here’s one specific example so you can see what I’m talking about here:

If you take a stereo track with a high frequency synth lead sound on the left side and a lower frequency synth lead sound on the right side and pan it to the left, you would expect to hear both the high and the low synth lead sounds panned to the left, correct? Well, guess what? Some DAWs are configured in such a way where panning a stereo track to the left does the following:

  1. It turns the left side up in volume.
  2. It turns the right side down in volume. 

The result? With our example above, if you panned the synth lead stereo track to the left, you would hear the left side high frequency synth getting louder and moving towards the left — but the right side low frequency synth on the right side would go down in volume. If you panned that stereo track all the way HARD LEFT – the high frequency synth would be heard in your left speaker but the low frequency synth would DISAPPEAR!

Believe it or not, until this knowledge is understood, many mixers who don’t fully know their DAWs don’t even realize this is happening with their stereo files, and their mixes are suffering as a result. 

There are simple ways to create actual true panning with stereo files in every DAW. Some DAWs are already set up that way. The bottom line? STUDY THE MANUAL!

A Word About Stereo and Mono Plug-Ins

Very similar to panning, different DAWs treat Stereo and Mono Plug-Ins differently. Again, STUDY THE MANUAL! I can’t say that enough. Every one of my students who actually studies the manual carefully – making sure that they clear up the meanings of words they don’t understand, and then making sure they practice, practice, practice with their DAW – succeeds with flying colors! I want you to be successful, so I strongly encourage you to study your manual thoroughly and carefully, and practice what you learn. 

Examples of Stereo and Mono Plug-Ins and Your DAW 

Some DAWs do not convert a mono track to stereo when you insert a stereo plug-in. Look at this example below. Notice the orange arrow is pointing to the output meter of a stereo reverb plug-in inserted into a mono lead vocal track. The plug-in meter clearly shows a different level on the left as compared to the right – a sure-fire sign that you are dealing with a stereo signal. However, the master output, when this track is solo’d (the blue arrow) shows very clearly that the output of this track is still mono (when the left and right sides of a stereo meter are moving exactly the same – this shows that the output signal is mono). Some artists, producers and engineers don’t know their DAWs well enough to understand that they may be robbing themselves of incredible width, depth, space and emotion from their mixes.  

What Happens If You Place A Mono Plug-In on a Stereo Track

Mono Plug-Ins accept information from one channel and output a signal only to one channel. It happens to be the left channel, because the standard for all DAW software programs is to designate the left channel as mono. This has been true for generations, going back to stereo hardware back in the ‘60’s and ‘70’s. 

Therefore, if you place a mono plug-in on a stereo track, don’t be surprised if your mix all of a sudden goes a bit whacko. The plug-in effect will only show up in the left channel. If you look at the orange arrow in the illustration below, this shows that the plug-in is outputting a mono signal (both left and right levels in the plug-in are identical), however, if you look at the stereo buss out meter with the vocal track solo’d, (blue arrow) you will see that the signal is very lopsided over to the left. In this case, the reverb is heard only on the left side of the vocal, and the right side is dry:

A Special Note About Drum Mixes

If you record a full drum set, or if you are given files from a drum session, and even if you are mixing EDM or Dance mixes with separate drum sample files (kick, snare, claps, hi-hat, etc.), know that each of those files may be mono or phantom mono stereo files when they are dry (free of any effects). If the recording or sample has effects on it already, it will probably be a stereo file. 

I prefer to work with dry recorded tracks and dry samples whenever possible. This allows me to have full control over my drum mixes. It’s very hard, if not impossible, to take reverb out of a track, or to un-compress a track. It’s very easy to add some reverb to taste, or to find your sweet-spot compression setting – as long as you start with dry files. 

A Word About Phasing 

When dealing with any mix, there is a chance that phasing problems will show up as you combine various sounds and effects. You can train your ear to listen to phasing problems. I often say, “Use your ear, not your gear as a priority when mixing.” I back that up with revolutionary music production ear-training exercises on The Lucrative Home Studio Masterclass. But you can start training your ear to hear phasing problems right now by doing this simple procedure:

  1. Take any snare track from any recording you have made in the past.
  2. Import it into a new empty session.
  3. Duplicate it.
  4. Turn Snap-To-Grid off on your DAW
  5. While listening to a loop of the snare only, start to slide the duplicated snare track to the right little by little. I’m talking just a hair at a time. After moving it slightly, leave it alone for 30 seconds or so, and listen very closely to the sound of the snare. Then move it again and listen for 30 seconds. Keep doing this. You will notice that the snare will lose its punch, its crack and its depth, its richness and its low end. It will start to sound weak and thin and wimpy. This is a phasing problem.
  6. When you slide the track more than 30 milliseconds to the right, you will soon start to hear a distinct delay. However, prior to hearing the delay, you will experience the snare going “out of phase.” The tone will change, the space will change. 

NOTE: Not all “out of phase” sounds are unpleasant. Some sound awesome and are the basis of how certain effects are created – such as a Wha-Wha Pedal, or Chorusing, or Flanging. 

Do this same experiment with other instruments and tracks. You will see that some instruments and certain ranges (high, mid and low frequencies) are affected more than others. 

Often times when I’m mixing drums, I will get rid of room mic tracks, overhead tracks, and “bottom snare” tracks. The more microphones used in a recording, the more chances for out-of-phase problems exist. In fact, there are times when I am fighting a drum mix to sound great, when all of a sudden, by muting room tracks, overheads and “bottom snare” tracks, the drum mix sounds awesome. This is not a rule or a law, but it’s happened enough times for me to pass on this morsel of wisdom. 

When dealing with mono and stereo tracks, mono and stereo plug-ins, and panning – you may encounter phasing problems. Learn to identify them and correct them. It’s not hard to do. Checking your mixes in mono is one great way to accomplish it. Like anything else it takes practice. But you can do it! 

Mid-Side Technology

Mid-Side recording, mixing and mastering is a separate animal all unto itself. It is neither stereo, nor is it mono. It’s a sort of hybrid of both, but not exactly. It’s a fascinating subject. I’ll be covering this subject in an upcoming TuneCore article, so stay tuned!

And finally, let’s not lose sight of the music itself! As I remind myself, so I will remind you — it’s not so much how we mix and master as it is WHAT we mix and master. Strive for creating emotionally moving music with impact and soul! 

We are all striving to complete our mixes and have them hold up to industry standards at the very least.

I’ve come up with a definition for a completed mix, and as you will see, it’s certainly not a technical definition:

The Definition of a Completed Mix: “No emotional weak links for the listener, from the very first note to the last moment of silence.”

Good luck creating great compositions and songs and completing great mixes!

Gary Gray is the teacher behind the Lucrative Home Studio online course. He’s an award winning composer, producer, and engineer, and has produced multiple projects for 20th Century Fox, Disney, Hollywood Records, A&E, EMI, CBS and many others in his home studio.

Tags: daw featuring mixing mono stereo