PANNING EXPLAINED
Today we look at panning, delve into the concepts of the “phantom centre” and "pan-law” and outline what you must keep in mind during your mix-down when sculpting your stereo image.
As demonstrated above, engineers use analog and digital pan-pots to alter the relationship between the left and right channel of a stereo signal, and thus the signal’s relationship with the rest of the mix.
Panning and creating a stereo image
The term “pan” is an abbreviation derived from “panorama,” and relates to the placement of audio signals within what is known as a stereo image.
It is used to help to create a perceptual illusion, and overall it helps construct the virtual listening environment of a stereo mix.
A little bit of background theory to begin with…
Audio engineers use panning to artificially play on our natural ability to localise a sound source’s direction - a process known as spatial or binaural localisation. This is the result of differences in interaural intensity and arrival-time, and the effects of the outer ears.
So what does this mean?
Our brains are constantly processing new aural information, and gauging location based on the differences in:
The volume perceived by each ear.
The arrival time of the sound at each ear.
The minuscule interaural time delays caused by the ridges of the outer ear.
The ratio between direct and reflected sound that is perceived.
Our sense of sound location is therefore largely determined by the perceptual differences between both ears.
If there are no interaural differences, the brain assumes the source is equidistant to each ear, and is perfectly centred in the stereo image.
In a stereo monitoring environment, this allows a listener to perceive the position of sound of the left & right monitor, and the equal monophonic audio content between them.
When you change the proportion that is fed to each monitor via panning, you change the interaural intensity and create the illusion of location within the stereo field.
(Source: Huber, 2018: 69-71)
The “Phantom Centre”
Stereo as an audio technology was invented in 1931, by Alan Blumlein at EMI Records - a hallowed studio site that most people now simply refer to as “Abbey Road.”
With the arrival of stereophonic playback systems, came the discovery of the phenomenon we refer to as the “phantom centre”.
It is the illusion of a middle speaker in a stereo monitoring setup, generated by the brain’s perception of equally balanced monophonic content from both the left and right channel.
This perceptual illusion can shift as the mix’s amplitude shifts from side to side. This can create an uncomfortable listening environment, especially if the playback system is widely spread across.
This is why cinematic playback systems operate using a format known as LCR (Left, Centre, Right) - ensuring the mono content of the mix is fixed to the central loudspeaker.
(Source: Owinski, 2017: 71-75)
Left, Centre, Right
As we have indicated already, the primary panoramic ares in a stereo mix are the left, centre and right. The centre is the most prominent aspect of a mix, adding solidity and prominence to the central sonic elements.
Whilst it is largely accepted by modern listeners that the most dominant aspects of a mix remain central, this has not always been the case.
In the early days of stereo as a playback format, there were all kinds of experimentations within the stereo field. It was not uncommon to see the vocals panned hard one side, and the backing track on the other.
When the likes of The Beatles and iconic engineers such as George Martin, Ken Scott and John Kurlander were experimenting with stereo placement, they created some of the 20th century’s most iconic music. During this era, they encountered a mechanical issue that would go on to shape the industry standard of today.
The hard-panning approaches of the 60s unearthed a major issue that related to disc-cutting, and playback on records. Imbalanced low-frequencies caused the cutting stylus to break the groove wall when the master record was being produced.
The only solution was to decrease the low-end energy to balance the sides, or to pan the bass, kick and anything else rich in low-end frequencies, to the centre. A special Elliptical EQ was invented for the mastering process to move all low-end to the centre to combat these issues.
For you electronic music producers, this EQing approach has become one of the integral foundations of mixing within the electronic genres (keep reading, we will come back to this shortly).
Audio Demo
The audio below is an excerpt from a track of mine, coming out on one of my favourite North American labels in the summer of 2023.
Both audio examples consist of a sum of the drum buss, 303 bass and Yamaha DX27 organ that I have used in the track.
Example 1 has no filtering on the sides below 150Hz.
Example 2 has the side content below 150Hz filtered by the Mid/Side EQ.
It is a subtle difference, but listen out for the improved clarity on the organ sound and the increased focus on the kick drum between 80/100Hz when we move all sonic content below 150Hz to mono.
Caution!**
As buss processing would impact the audio, I have left the audio uncompressed and at pre-master volume (-24 LUFs). Please be wary of this and be careful with any audio you feed to your headphones or monitors afterwards as it might be significantly louder!
The Equalisation used on Example 1 (audio below)
The Equalisation used on Example 2 (audio below)
Big Mono
With the arrival of stereo and pseudo-stereo (one side chorused a little sharp in contrast to the original signal) keyboards, music became larger and wider than ever before.
This tempted engineers at the time to pan these signals hard left and right on top each other, creating what Owinski coined as “Big Mono.”
Big Mono relates to the lack of definition in a mix, caused by stacking stereo audio panned hard right or left. This erodes the sense of panorama and depth as everything is jammed on top of one another.
You can easily avoid this by not making such drastic panning decisions, adding width and interest from other approaches such as adding modulation or time-based effects.
(Source: Owinski, 2017: 73-4)
Pan Law
You may have already encountered the term “pan law” in your DAW’s preference settings.
To put it simply, some pan controls reduce the gain of the left or right output as the pan pot is centred. Others raise the level of the side the pan pot is moving towards. The amount by which the signal level is affected is known as the “pan law.”
These laws are important when a sound is being panned across a stereo image and you wish for the sound to be perceived at a consistent level.
Linear Pan Law
If you want this panoramic motion to be perceived at a constant volume, the centre attenuation needs to be -3dB. This is due to the summing of two equal audio signals being perceived to increase volume by +3dB.
This is the law to use if your intended audience will be consuming the media via a stereo configuration. This approach is known as “Linear Panning.'“
Constant Power Pan Law
If you intend for the panoramic motion to be perceived at a constant level when summed to mono, the attenuation must be increased to -6dB as the electrical summation of equal signals creates an amplitude that is +6dB greater.
This would be the appropriate choice if your audience is listening via a mono sum, such as in a nightclub, on the TV or radio, or a mobile phone. This approach is known as “Constant Power Panning.”
Pan Law and DAWs
Consequently, most mixing desks and DAWs will offer a compromise between these options - with around -4.5dB attenuation. This is a format that works in most instances, with negligible variation in perceived volume across listening formats.
Most DAWs will offer the choice to customise these options, but their default configurations can differ. This is why a mix identically bounced between two different DAWs may sound different, so it is worth keeping in mind!
Creative Panning
Alongside time-based effects such as delays and reverbs, panning is used to add space, depth and motion to a mix. It allows engineers to construct artificial acoustic environments that can both emulate real-life and transcend realism -taking mixes into other-worldly or hyper-realist states.
The advent of new spatial technology such as Dolby Atmos, now means that engineers can go well beyond the traditional confines of stereo panning left and right. But this is a whole can of worms for another day.
Audience vs Drummer Perspective
A good example of adding realism would be the use of drummer vs audience perspective when panning your drums. These techniques allow engineers to place a listener’s perspective, adding realism and improving the listening experience.
Audio Demo
The audio below is from an Ableton Live Drum Rack, I have panned the first example using Audience Perspective and the second with Drummer Perspective.
The differences are subtle, listen out for the placement of the snare drum, and the directionality of the tom-roll as an indication.
Caution!**
As buss processing would impact the audio, I have left the audio uncompressed and at pre-master volume (-24 LUFs). Please be wary of this and be careful with any audio you feed to your headphones or monitors afterwards as it might be significantly louder!
As the name would imply, “Audience Perspective” pans the rhythmic elements of a drum recording in a manner whereby the listener is placed in front of the virtual performance emulated in the mix.
As the name would imply, “Drummer Perspective” does the inverse of this, and places the listener in the drummer’s seat.
It is worth noting that when using either of these approaches, you must ensure that the original audio signals are panned in a manner that is both congruent to any overhead / room mic channels, and any auxiliary sends as this can drastically impact the listener’s perception of location.
How you approach this process will largely be influenced by the nuances of the genre you are working with, the source audio, and your own personal preferences.
Stereo width and the use of panning ebbs and flows over time as creative taste and fashion in engineering changes.
Try to listen to some of your favourite tracks from different eras, and listen to how much variety there is from genre to genre!
What about drum machines and electronic music?
Certain genres lend themselves better to realism, others have their entire sonic identities rooted in hyper-realism (intentionally accentuating sonic characteristics) or surrealism (disregarding the need for sonic realism altogether).
Many modern genres are defined by physical limitations of their typical listening environments (such as the playback systems in nightclubs). For instance, the hard-panning found in an experimental 60’s track would be wholly unsuitable for playback on a club sound-system.
With this in mind, I would mix and pan the drums on a dance track in a completely different manner to an indie or pop track with acoustic drum recordings.
Audio Demo
The audio and infographic below demonstrates a typical stereo image used in a house track. This is a track on mine out on the French label - H24 Musique.
Using the infographic below, listen out for the stereo placement of the core and supporting sonic elements of the mix.
Caution!**
Unlike previous audio examples that do not have buss compression, this is a mastered track - so will be louder than past examples. Please keep this is mind and adjust your playback volume accordingly!
I have included an example a stereo image for my track - “Let’s Dance” [H24 Musique] below.
This is a typical stereo image for a house music track. As you can see - most of the rhythmic elements tend to remain close to the centre, if not central. I use a Middle/Side EQ to put everything below around 150Hz into mono - this removes low-end mud and helps to solidify the mix.
Concluding remarks
I often tell my mixing clients that the mastery of location, space and depth is one of the primary factors in elevating a mix from being good, to being of “professional” industry-standard.
The use of panoramic stereo fields can add clarity, motion, interest, depth and width to a mix. For this reason, it is imperative that aspiring engineers explore the various options available to them, reconciling this process with broad genre-dependent nuances, as well as personal preferences.
Article Sources / Further Reading:Carnegie Mellon University. (N/A). Loudness Concepts & Panning Laws. [Online]. www.cs.cmu.edu Last Updated: N/A. Available at: https://www.cs.cmu.edu/~music/icm-online/readings/panlaws/ [Accessed 22 February 2023].Huber, David Miles. (2018). Modern Recording Techniques. 9th ed. New York, New York: Routledge.Owinski, Bobby. (2017). The Mixing Engineer's Handbook. 4th ed. Burbank, California: Bobby Owinski Media Group Publishing. Robjohns, Hugh. (2016). Q. What pan-law setting should I use?. [Online]. https://www.soundonsound.com. Available at: https://www.soundonsound.com/sound-advice/q-what-pan-law-setting-should-use [Accessed 22 February 2023].