Today, most of us enjoy sound in stereo on a regular basis. However, It hasn't always been this way-- in fact, stereophonic sound is a relatively new concept when considering the complete history of sound and how we experience it.
As a musician, it's important to understand the origins of stereophonic sound, especially when it comes to making decisions like choosing to record in mono vs. stereo, or testing your mix for playback before pumping out the final master. Below, we'll share everything you need to know about stereophonic sound so that you can confidently assess your decisions as both an audio engineer and an avid music listener.
What is Stereophonic Sound?
Stereophonic sound or stereo sound is a type of sound reproduction that uses multiple independent audio channels. Utilizing two audio channels or more creates the illusion of 3D sound to the human ear, giving stereophonic sound a characteristically wide, rich sound. Stereo recordings are the dominant sound reproduction technology of today, and are held in contrast to mono recording or sound reproduction, which reproduces audio appearing to stem from a single source.
The History of Stereo Sound
Today, we don't think twice about choosing to listen to our music on stereo playback devices, but that wasn't always the case. Here is an abridged history of how the stereophonic sound system developed and how it's shaped the way we experience sound today:
HiFidelity Sound
An interest in high-quality auditory experiences has been around since the late 19th century and 20th century with the development of gramophones and phonographs. While it was revolutionary to have an accessible sound source tied to a copy of music, the audio quality was somewhat limited. With advancements in electrical recording and the production of more robust physical records, sound began to improve.
Having a hi-fidelity sound system was a mark of luxury or keen interest in audio, and audio fidelity records began to amass a group of enthusiasts in the mid-20th century who took it upon themselves to build their own sound reproduction systems using a variety of individual parts.
Alan Dower Blumelein and Binaural Sound
Alan Dower Blumlein is largely accredited with the development of an early version of stereophonic sound. In 1931, he patented a two-channel recording system, with the idea to make audio more immersive by playing to the design of the human ear, coining the term binaural sound. His technique the "Blumlein Pair" is still used in the world of audio engineering to this day.
The Creation of Stereophonic Records
In the 1950s, technology had developed to the point where stereo recordings were ready to be enjoyed on a mass scale. Label RCA revolutionized the space by putting out the first stereo LP on vinyl in 1958, starting a wave in shifting consumer tastes. The home audio equipment boom of the 1960s further cemented stereo as the dominant listening format for audiences as we know it.
The Continued Evolution: Surround Sound and Beyond
Today, we continue to see the evolution of sound as we know it. The introduction of technologies like surround sound started with an idea: while today, a score can be specifically mixed according to surround sound implications, the experience was originally created using a mono optical surround track.
In this arrangement, the main score and sound reproduction of the film would play in mono, but certain sound effects and ambient noises could be played at certain points in the film to create a more immersive experience.
With the development of modern technologies like Apple's Dolby Atmos for AirPods, there's no limit to building a more interactive experience for listeners.
Stereophonic Sound Vs. Monophonic Sound
The key differences between stereophonic sound and monophonic sound can be condensed to using multiple audio channels in sound reproduction systems (stereo) or a single audio channel (mono). The number of audio channels greatly affects how a sound is perceived by the human ear, with stereo sound having a noticeable separation between what the left and right ears perceive.
Monophonic sound has been around for longer, creating simple, clear, and fairly consistent mixes. Stereophonic sound by contrast tends to have more depth, and creates the feeling of spatial separation, acting as more immersive audio. Most records today are experienced in stereo with the exception of some live settings where a piece may be played back on mono.
Some musicians may choose to adopt a mono sound or mix to produce a certain effect or sound profile in their mixes.
Visualizing the Stereo Field
When crafting and experiencing music in stereo, it can be helpful to have a strong visualization of your mix. Fortunately, this is a skill that can be developed with a little guidance and active listening. Take a look at the visualization method outlined in this classic mix manual:
A key takeaway when visualizing recorded music is that the strongest and most forward sounds tend to rest in the middle of the field. Only stereophonic recordings create this multidimensional separation from one side to the next, due to processing sound on two or more independent audio channels.
Essential Tips for Stereo Mixing: Widening the Stereo Sound
Most of us experience stereophonic sound on a regular basis whether that's jamming out in the car, or listening to music on headphones. That being said, if you're making music, you'll most likely be crafting your sound in stereo. Here are some top tips for making your sound stretch the full length of the stereo field.
1. Check Your Mix In Mono
While it may sound counterintuitive, it's always a good idea to check your mix in mono. Even though your mix will most commonly be experienced in stereo, hearing it reduced to mono can help you create a great foundational balance of the tracks and weed out competing frequencies that might otherwise be challenging to identify across the width of the stereo field.
Many audio engineers swear by starting their mixes in mono, before transitioning to a stereo sound for these reasons. In Ableton Live, you can do this by placing a "Utility" on the master track and setting it to "mono". Once you're satisfied with the balance of your mono mix, remove the utility to continue building in stereo.
2. Put Panning to Good Use
Panning is a lot more than deciding whether a track should sit left, right, or center. Placing a track within the stereophonic sound system opens up a whole host of artistic decisions. Take into account that centered tracks tend to hold more prominence and strength than those on the left or right side of the field.
For instance, when mixing vocals, it's not uncommon for the main vocal to be centered while the harmonies or backing vocals are placed across the wide breadth of the stereo field. Panning holds power by communicating balance in relation to the rest of the mix.
3. Create a Balance Between Stereo and Mono Tracks
Not everything, or every part of a mix, should necessarily be widespread. Instead, consider creating moments of width with wider pans, and more tracks outside the center of the stereo field. Contrast this with more narrow sounds to build momentum between verse and chorus or different sections of a song.
4. Use the Haas Effect
Panning isn't the only way to create width. One way to build a larger presence in your stereo system is to use the Haas Effect. In this technique, two of the same audio tracks are duplicated, though one is played at a slight delay (usually a couple of milliseconds) after the first. The result is a stand-out effect you're bound to notice in your mix, take a listen for yourself:
5. Test Several Playback Devices
As with any stereo sound, you should make multiple playback stereophonic sound attempts on various devices before pumping out that final master. A widened stereo field can leave more room for error, so it's particularly important to keep an ear out for things like phasing issues.
Stereophonic Sound FAQs
Ready to live life in stereo? Consider these commonly asked questions and answers to help you build your signature sound.
What is the meaning of Stereophonic sound?
Stereophonic sound, otherwise referred to as stereo, is a processing method that creates a three dimensional auditory experience. Three channel stereophonic sound is in contrast to mono sound, or monophonic sound, which is sound reproduction that appears to emit from a single source.
What is an example of stereophonic?
The best way to understand stereophonic sound is to take a listen to a stereo demonstration record, or a piece of art that relies heavily on the stereo field to convey it's message. Mr.Brightside by The Killers is a great example of this with the opening riff and drums separated exclusively to one side of the field than the other:
What is difference between mono and stereo sound?
The difference between mono and stereo sound has to do with the processing of the audio. Whereas mono sound recording feels as though its coming from a single source, a stereo recording creates the feeling of a 3D space.
What is the difference between stereo and stereophonic?
Stereo is simply shorthand for the term stereophonic. Stereophonic sound holds a more formal connotation, creating a three-dimensional space for audio. "Stereo" could be used to refer to this, but it could also refer to a two channel audio system, such as a set of left and right speakers.
Stereophonic sound forever changed how we experience audio and music as we know it. Hopefully, this article serves as a helpful guide detailing the similarities and differences between mono and stereo sound, and gives you a bit more background on the history of high audio fidelity records. Use the history of stereophonic sound and your knowledge of the stereo field to enhance your art.
