Why to work in Stereo
Humans have two ears on their head for the same reason they have two eyes. Much like the way our eyes work together to give us depth perception, our ears work together to provide a perception of space. For this reason, I encourage you to record and mix in stereo.
We get a lot of projects in the studio that have been recorded by musicians in their home and brought in for mixing. One of the most common problems I notice in these recordings is that people fail to pay attention to the stereo spectrum. While not every instrument is suited for stereo use, the majority of acoustic instruments as well as synth/keyboard instruments will benefit greatly from proper stereo recording.
It’s probably easiest to start by explaining when NOT to consider stereo recording. When sound originates from only one single location, and you are using close mic techniques, you won’t benefit from Stereo recording. This is best demonstrated by things like lead vocals, single speaker guitar amplifiers, individual drumkit pieces, and direct signals from a guitar or bass. For all these sources, using a single channel of your mixing board and panning as desired will provide the best result. I should point out that things can change if any of the aforementioned instruments are being used with room mic’ing techniques – more on that later.
How to work in Stereo
There are several methods of placing a pair of microphones into a stereo recording configuration displayed in the image below. You’ll have to try them and decide for yourself what sounds good on each instrument. You’ll be surprised just how much these techniques will enhance your recording. Even on things like an acoustic guitar or a simple hand drum like a djembe, stereo mic’ing makes the recording sound more like our natural perception of the instrument. After all, we have two ears and instruments create resonance from all around, that sound then bounces around the room and hits us from many angles. Increasing the distance between the sound source and microphones will capture more of that “room” sound. Sometimes adding a second set of mics solely to capture the room tone can completely change the vibe of your recording.
Even when there are no acoustic instruments involved, it is important to record your electronic instruments in stereo. Most synthesizers, samplers, drum machines, and keyboards have a left and right audio output. USE THEM BOTH! Things like a Hammond B3 organ sound are made for stereo, as well as all digital piano sounds – like a real piano, the lower notes create more sound on the left output, and the higher notes are louder on the right. Drum samples are made to sound like you’re in the room with a drum kit – you’ll hear hi hat on one side, ride cymbal on the other, and the toms will roll across the stereo spectrum.
Understanding Stereo Channels & Panning
Now that we’ve discussed what to record in stereo and why, lets talk about how your DAW or mixing console functions with a stereo track. On both hardware mixers, and software mixers (circumstances may vary depending on gear), you’ll see the ability to use a mono channel/track as well as a stereo channel/track. On a hardware mixer, mono channels have a single input and stereo channels have a left and right input. On software mixers/DAW’s mono tracks show a single waveform and corresponding meter, while stereo tracks fit two waveforms into one lane and show a meter split into left and right level displays. The concept of having a stereo channel vs using 2 mono channels is simple – it allows you to make adjustments to both the left input source and the right input source simultaneously with one set of controls. In fact, you could obtain identical results by using two mono channels, but you’d have to turn twice as many knobs, move two faders, and use 2x the plugins to obtain the identical result.
That’s all pretty straightforward, where things get confusing is how PAN controls work on stereo tracks vs mono tracks. The first thing to recognize is that when a signal is played at 100% volume out of one speaker only, then panned center making the same signal come out of both speakers, it actually needs to get quieter to maintain the same level of perceived volume. This is called the “STEREO PAN LAW” and is typically -3dB on most consoles and -6dB in some scenarios.
On a MONO track – the pan will move 100% of the signal across the stereo spectrum from Left to Right, wherever you choose. As the signal is panned center both left and right channels will be adjusted by your stereo pan law.
Mono panned all the way left= 100% of signal to left speaker
Mono panned center = 100% -3dB of signal to both speakers
Mono panned all the way right = 100% of signal to right speaker
On a STEREO track – the panning of each input is “locked” at hard left and hard right, meaning the left audio signal/file only comes out of the left speaker and the right audio signal/file only comes out of the right speaker. If you were to pan a stereo channel in your DAW you aren’t actually moving audio from one speaker to the other, you’re just lowering the volume of one of the stereo channels
Stereo panned all the way left = 100% of LEFT CHANNEL to left speaker
Stereo panned center = 100% of LEFT CHANNEL to left speaker 100% of RIGHT CHANNEL to right speaker
Stereo panned all the way right = 100% of RIGHT CHANNEL to right speaker
If you’re still reading, congratulations! You hopefully have a better understanding of how to record and mix while taking advantage of stereo content. As always, let me know if you have any questions!