Digital Audio for Public Historians (2): Mono and Stereo

In this second installment for “Digital Audio for Public Historians,” I want to have a look at one of the basic recording options available on mid-range recorders: the option to have a mono or stereo recording. 

There are hundreds, if not thousands, of articles on mono vs. stereo online, and I’m not going to go into great depth about them, because the simple fact is that the large majority of public historians will likely never use stereo.

The best way to understand mono and stereo is to put on your headphones (put on your headphones now). 

A mono (or monaural) recording is a recording that imagines that all sound comes from a single point of origin. Because of this, even if the listener has multiple speakers, the recording will send the same information to each of them. For example, your headphones have two speakers. In a mono recording the same signal comes out of both speakers (i.e. the speaker in your left ear has the same output as the speaker in your right ear). In technical terms, the sound has a single channel.

Of course, users can manipulate the sound coming out of multiple speakers. They might adjust volume or treble on each of the speakers, but at the end of the day the recording is sending the same information to all output devices.

Here is an example of a mono recording—the type that public historians deal with all the time. It’s the famous debate between James Baldwin and William F. Buckley at the Cambridge Union in 1965.

While you’re listening, remove the headphone from your right ear. You will notice, that you are still getting all of the same information that you were getting in your right ear. Reverse the process. Notice that what you are hearing in your right ear is the same thing that you’re hearing in your left ear.

For oral histories and interviews, most audio producers prefer mono. To understand this, we need to know a little but about stereo recordings.

Stereo (or stereophonic) recordings have two channels of sound meant for two speakers. This allows audio producers to have recordings that send different information to different speakers. Rather than imagining sound that comes from a single point, as with mono recordings, stereo recordings create the illusion of sound coming from more than one direction. A “true stereo” recording is created by recording sound using an assemblage of mics that output to two or more audio channels (as opposed to an “artificial stereo” recording in which producers transform mono signals into multichannel recordings in postproduction).

A basic true stereo recording requires at least two mics situated relative to a sound source so that they create complementary recordings. Outputting each microphone’s recording to a different channel enables the speakers to each produce different information. When done creatively, these recordings can create a sense of space for the listener. The next video is an example of natural stereo sound. Notice that you are hearing different inputs from the two channel recording—so much so that it sounds like bees buzzing around your head.

It would be disorienting to hear two people have a conversation—with one speaking in your left ear and the other speaking in your right ear—and not have them present. So, for the most part, you will record your oral histories, interviews, etc. in mono.

Even for more complex recordings, many producers prefer mono. This is especially the case with music recordings, so public historians working in this space should be attentive to some of the strengths and weaknesses to mono and stereo recordings.

We’re going to use two famous albums from 1966 as our examples.

In May 1966, the Beach Boys released the album Pet Sounds, musician and producer Brian Wilson’s opus. Pet Sounds is a complex piece of music, with layers upon layers of sound. At the time Wilson was mixing it, the stereo format was becoming popular. The problem with stereo albums, as Wilson and many other producers recognized, was that they required proper speaker spacing and balancing on the part of the listener. If the position of the speakers vis-à-vis listeners was incorrect, the benefits of stereo were lost. And, for these audiophiles, fidelity to the original intent of the musicians and producers was paramount. So, Wilson stuck with a mono recording.

Here’s an example of what that sounded like.

Pet Sounds was a primary influence on Sgt. Pepper’s Lonely Hearts Club Band by The Beatles. Released the following May, Sgt. Pepper’s helps illustrate the pros and cons of mono and stereo.

Take, for example, the mono version of Lucy in the Sky with Diamonds (known as Original Mono Mix - No. 11). It is not the version on the original album, but it gives a really good sense of how mono works.

Notice how the sound is exactly the same in both ears. You could take off one side of your headphones and still hear everything that has been packaged into the recording.

As fans of The Beatles know, soon after its original mono release, Sgt. Pepper's was released as a stereo recording. And, many of us have grown up listening to one stereo version of Sgt. Pepper's or another. In 2009, Calderstone Productions Limited released a stereo remix, which is the version of Lucy in the Sky with Diamonds below. Compare it to the mono recording.

After hearing the mono first, this version can be a little disconcerting. Immediately, we are struck with a sounds that seem to be swirling around us. There is no way to listen to this version of Lucy in the Sky with Diamonds without both headphones.

It's this difference that distinguishes mono and stereo. And it's this distinction that helps demonstrate why most of the recording we do as public historians will be in mono. Most of us simply don't need stereo.

There are exceptions, of course. Some of us will be making documentaries. Others of us might consider experimenting with sound as part of our research practice. In these cases, we may want to go beyond stereo recordings and use 5.1 or 7.1 surround sound, which is what we experience in most modern movie theaters. I won't talk about these more advanced techniques in this series, since we won't be using them in our class, but I might consider a future post on them.