I do a lot of listening in mono these days.

Partly, it’s a seasonal shift I make each year: The transistor radio sounds right to me in summer. Monaural AM radio reception changes with the weather, the temperature, the time of day, and just as we expose our bodies to the elements more in summer, it makes sense to me that audio should do the same. Plus, mono suits summer broadcasts so well: baseball games, violent storm warnings, the local oldies station (which plays mostly mono records anyway). How would stereo improve any of these?

You might assume this is nostalgia. And yes, I’m old enough to have heard Nixon’s resignation on a transistor radio interrupted by lightning strikes in a tent somewhere in Maine 40 years ago. But that scratchy broadcast sounded historic to me even in 1974. I grew up with baseball and politicians on TV, not radio, and I’m very much a child of the stereo era. My first radio (also the first object I remember thinking of as my own) was built for stereo FM, boasting about it all over the chrome dials. The Dark Side of the Moon, that touchstone of cinematic stereo wonder, was released right on time for my adolescence.

So why the attachment to single-channel audio? One clue is the other listening I’m doing a lot of right now, as live-in house engineer for Damon & Naomi. Our next album, like the previous ones, will be in stereo—but I listen to each take as it goes down, and hear them back as I edit, in mono. Which is pretty much how it goes if you overdub one instrument at a time, as we (and so many others) often do. By definition, a single mic generates a mono signal. Get fancy and set up two or more, and you still have to check them in mono to make sure they aren’t cancelling each other out rather than reinforcing one another. I’m sure I’m not alone among engineers in saying that I hardly do any stereo listening in the studio before mixing—yet then we all mix in stereo en route to the final product. What happened to mono mixing?

It’s not that it sounds lame. Brian Wilson mixed Pet Sounds in mono not only because it was still the dominant commercial format in 1966, but because he is deaf in one ear. One of the greatest music producers ever “can’t totally comprehend stereo,” explained Capitol Records when they released a (truly lame) stereo mix of Pet Sounds in 1997. And the fully binaural Beatles, together with producer George Martin, spurned stereo in favor of mono when given the choice—their landmark studio creations Revolver and Sgt. Pepper’s Lonely Hearts Club Band were released both ways, but by many accounts the band and producer fussed over the mono versions only, leaving stereo for Abbey Road engineers to work out.

Stereo may have seemed to them like a faddish product back then, a lifestyle accessory more than a musical one—like the short-lived quadraphonic format would become later, or perhaps a bit like 5.1 surround sound is today. “The Stereo Scene” was the name of Playboy’s audio column at the time, aimed at a man the magazine described as, “in the midst of the biggest buying spree of his life. Cars, cameras, and hi-fi cabinets. Clothes, cognac, and cigarettes.”

An ad for the KLH Portable Stereo Phonograph in the October 1962 issue of Playboy, via flickr.

At least the Beatles had their engineers spend a bit of time on a stereo mix. Rudy Van Gelder, the great jazz recording engineer who ran so many classic sessions for Blue Note Records—with Miles Davis, John Coltrane, and Thelonious Monk, to name a few—from his studio in Hackensack, New Jersey, made sure that stereo versions could be produced alongside mono ones as needed, but later confessed that no one even checked them. “The creative part of those recordings was done in mono,” is how he once put it to an interviewer.

Van Gelder’s attitude toward stereo jibes with the Beatles’: It was a commercial demand that had to be fulfilled, ideally without compromising the mono version that everyone working on the recording really cared about. That’s a lot of golden ears passing judgment. We have two ears because stereo hearing is important to our evolutionary ability to locate sounds in space. But could it be that it isn’t so important to music?

Listen to the Beach Boys' Pet Sounds track "Here Today" in mono and stereo:

The history of stereo recording in fact includes a lot of feet-dragging, even though the significance of binaural hearing to our senses made it a natural focus of interest from the very beginning of electrical sound transmission and recording. In 1881—just a few years after Bell’s 1876 patent for the telephone and Edison’s 1877 invention of the phonograph cylinder—a stereo phone system was demonstrated in Paris, for listening to the opera at a distance from the theater. Multiple transmitters at the foot of the stage relayed distinct signals to two handsets, one of which was held to each ear for a stereo experience of the live performance in progress. For a time, this Théâtrophone existed in Paris and a few other European capitals as a commercial service. Marcel Proust was a subscriber.

Théâtrophone poster by Jules Cheret, 1896

Yet it would take another 50 years for stereo recording to even begin to take shape. In 1931, a remarkable engineer named Alan Blumlein at EMI in London published a paper establishing patents for stereo recording, stereo records, and stereo disk cutting, all of which are applicable today. (A standard way to arrange two microphones for stereo recording is still called “a Blumlein pair.”) By 1934, Blumlein had demonstrated the functionality of this technology by recording and cutting a stereo record of the London Philharmonic Orchestra performing Mozart’s Jupiter Symphony at the newly constructed Abbey Road studios.

But Blumlein’s bosses were unimpressed, apparently. Stereo recording was shelved, and the engineer was put to work developing a different new technology instead: television. (His patents in that field were also groundbreaking, and the BBC would go on to broadcast the first public high-definition television signal in 1936.) When World War II arrived, Blumlein’s prodigious talents were reassigned to the military—his subsequent work on airborne radar was considered so important to the British war effort that when he was killed in a test flight over Wales in 1942, Churchill ordered his death be kept secret.

Blumlein had invented stereo recording when he was 28 years old and died at 38. But he would have had to live past retirement to see that invention widely adopted. The first commercial stereo records weren’t released until 1958, and it would take another 10 years before they became standard. The world of 1968 undoubtedly would have surprised Blumlein in so many ways… except in the realm of hi-fi.

Tellingly, Blumlein’s initial inspiration for the invention of stereo recording was not an audio experience, per se. His biography, The Inventor of Stereo, tells an anecdote about Blumlein going to the cinema with his wife and complaining that the actors’ voices didn’t move with them across the screen. “I’ve got a way to make it follow the person,” he then said to her, in what may have been his eureka moment.

Perhaps Blumlein thought of stereo at the movies rather than at the Philharmonic, because stereo’s realism is related to how we hear sounds in motion. If we always walked around an orchestra while listening to it, hearing their music from a fixed point would seem a paltry representation of the experience. But so many of our musical experiences are static: played by instruments in a single position and listened to from a single position. If Blumlein had been working in Rio and trying to record the audio of a Sambodromo, where bands play while marching and dancing, the reaction from his bosses may have been more enthusiastic.

Because of our naturally binaural hearing, stereo recording is more “realistic” in the sense that it better resembles our audio experience of the world at large. “Living Stereo” was the evocative phrase RCA used to describe their stereo LPs, because the sensation of listening with two distinct signals is ostensibly more like the listening we do in life. Even the letters of the “Living Stereo” logo seem to be so charged with vitality that they can’t sit still.

But fidelity to sound at large is not necessarily the same as fidelity to how we listen to music. Out in the world, we tend to pay attention to live music only under certain conditions—emanating from a stage being the most familiar in Anglo-European culture—and with a listening position directly in front nearly always considered the best. But having two ears isn’t necessarily helpful when we want to listen to a musical sound source that is already directly before us, fixed on a stage.

Consider one of the most famous European halls for live music: At La Scala in Milan, the Empress Maria Theresa’s royal box is at the very back, in the center—the only point in the house where audio emanating from left and right are perfectly balanced. If you sit in the royal box at La Scala, either ear will do; Brian Wilson would miss nothing. Meanwhile, even a shockingly expensive seat to one side of the orchestra—I am speaking from personal experience here, without too much bitterness—receives imbalanced sound from the stage.

But here’s a seeming paradox: Were the sound projected off the stage at La Scala a mono recording of an opera, rather than the real event in “living stereo,” the balance of the music would be the same throughout the hall. Which may be precisely why Alan Blumlein’s bosses failed to be impressed by his stereo recording of the London Philharmonic in 1934. Mono already sounded to them like the best seat in the house.

La Scala pictured from the stage – the royal box is at the back, sharing a centered left-right balance with only the conductor and a handful of cheap standing room or upper tier seats.

This helps explain the reluctance among 20th-century musicians and producers to adopt stereo recording. If the goal of a recording is to fix an ideal balance of sounds heard in the studio—as Rudy Van Gelder put it, how the musicians “sounded in relationship to each other” at that particular moment, in that particular space—why use an audio device we associate with sounds in motion? When Brian Wilson was told by Capitol that they wanted to produce a stereo mix of Pet Sounds, he raised an objection unrelated to his own hearing. “Brian explains that he always wanted his records to be in mono so that he would be in control of the listening experience,” the liner notes to that egregious stereo mix confess. “With mono, the listener hears it exactly with the balance that the producer intended. With stereo, however, the listener can change the mix, just by the turn of a balance knob or speaker placement.”

Which gets back to why I listen to mono in summer. There’s no negotiating speaker placement by the barbeque in the backyard, or on a blanket at the beach. Even if you brought a portable stereo along with your date, like that swinger in the Playboy ad, and fussily set speakers up in an ideal position, and then sat still… the wind would do enough to throw the balance off.

Not to mention, you’d look like a dork. Stereo on the beach is the aural equivalent of wearing socks with sandals. And Brian Wilson liked to play his piano barefoot on the sand.