Words by Anton Spice

It has been called the “oldest and most universal sound effect in music”.

An acoustic quality that gives the sound its shape, it becomes the roots of a recording in a physical environment and opens up an emotional register in the listener that goes beyond melody or harmony towards something altogether less tangible. Derived from the phenomenon of reverberation – or the persistence of a sound after it is produced – the very ethereality of reverb makes it both an elusive idea and a creative device. As Michel Chion wrote in his 1993 book Audio-Vision: Sound on Screen, “the more reverberant the sound, the more it tends to express the space that contains it.” To understand how this works in film composition, we need to dig a little deeper and go back a little further than the age of cinema.  

The acoustic properties of physical environments have long had an impact on the organisation of society. Analysing rock paintings in the southwestern United States, archaeoacoustics researcher Steven Waller identified a greater prevalence in sites with more reverberant acoustic qualities, suggesting that sound was a crucial factor in the nomination of sacred spaces. It is thought that some pre-Columbian temples in Mexico and Peru were designed to either project or reflect the human voice. In Europe, the development of Gregorian chants was intimately connected to the cavernous abbeys in which they were performed. The layered and delayed polyphonies caused by reverberation were not just the consequence of the relationship between physical space and the music, but the intended effect.

Just as the reverberation inherent to religious spaces bestowed a God-like tone on the orator, so did the echoic qualities of the church induce a feeling of awe among the congregation. In engineering parlance, ecclesiastical music used the church as an instrument to enhance the emotive quality of the music and impress its message of power, control and reverence on the listener. From a religious or political perspective, reverberation exuded a grandeur designed to make the individual feel deferential in the presence of higher forces.

Of course, churches weren’t the only places where the construction of space had acoustic implications. Chamber music, as the name suggests, was written for the furnished rooms in which it was performed, just as concert halls were engineered to suit the dissemination of orchestral music, or as subterranean punk clubs were perfect for absorbing the percussive force of a live drummer. If reverberation is an expression of how sound moves in space, then for a long time it was the physical space that impacted both the sound of the music and the kind of music produced.

The most reverberant man-made structures in the world are the 240m long oil tanks at Inchindown near Invergordon in Scotland. Built during the Second World War as bomb-proof oil stores for nearby military bases, their shape and material quality – where residual oil smoothed the surface of the concrete to lessen the amount of sound absorbed – created a reverberation which acoustic engineer Trevor Cox measured as lasting up to 112 seconds from high-frequency sound to silence. And yet, when Cox entered the tanks to make his measurements, his first impression was a cinematic one. “Entering the oil storage complex … felt like walking into a villain’s secret lair in a James Bond film,” he wrote in his 2014 book Sonic Wonderland. Embedded within this observation is an intuitive response to the emotive qualities of reverb – a sense of jeopardy, melodrama and tin-pot malevolence in the long-held echoes of Cox’s footsteps on the damp ground.

Inchindown is an extreme example, and more often than not the application of reverb in film music is subtler and much less perceptible than would be heard in a 240m long oil tank. Reverb traces the contours of a room in a way that is often difficult to hear – a phenomenon that academic Sean Street has called the “poetic acoustic, or sonic character of Place.” As Street wrote in 2020 book, The Sound of a Room, “central to the aural character of where we are at any single moment is how a space changes the seed of a sound through reverberation and resonance.” The space in which a sound is made and heard will have a defining impact on its character. In Apichatpong Weerasethakul’s Memoria, a film structured around sonic experience, it is telling that the first question the audio engineer asks Jessica (Tilda Swinton) as he tries to recreate her mysterious sound is, “where did you hear it?”

AIR Studios is one of the few recording studios that exploit the architectural acoustics of a church. Built in a Romanesque style in 1884 by Alfred Waterhouse, the architect of the Natural History Museum, AIR Studios’ current home at Lyndhurst Hall in Hampstead, North London, was first a church and missionary hall whose hexagonal shape was designed for congregational singing. In 1992, producer George Martin took over the hall, bringing in an adjustable acoustic canopy and transforming the religious space into one of the world’s largest live rooms, capable of accommodating full symphony orchestras and a choir in a single session.

The roll call of Oscar-winning (or nominated) soundtracks recorded in Lyndhurst Hall is as impressive as any and give an indication of just how broad a palette this reverberant space can offer. These include Atonement by Dario Marianelli, How to Train Your Dragon by John Powell, The Grand Budapest Hotel by Alexandre Desplat, The Whale by Rob Simonson and Phantom Thread by Jonny Greenwood. One composer though who has developed a long-standing love affair with the acoustics of Lyndhurst is Hans Zimmer, whose rousing score for Interstellar is among several he has recorded at AIR. In an online Q&A from 2012, Zimmer outlined the reason for this in more detail.

“I write very strategically for the spaces I record in,” he explained. “For instance, the Hall at AIR Studio has a gallery, so I put my horns up there above the orchestra in Batman. The space you have people perform in is as important as the quality of their instruments. Players respond to good acoustics and will give you a better, more committed performance … Especially brass players like "using" the reverb in the room to give them time to catch their breath between notes, so they'll have the courage and strength to play the next note stronger.” In this context, it is the potential for reverb which not only enhances the recording but the performance itself. “I like recording in churches and halls, not studios and artificial reverb,” Zimmer continued. “But if your budget is a bit tight, try a school auditorium. Or an empty warehouse. Use your imagination.”

For as long as the quality of reverb was limited to the room in which you recorded, imagination and ingenuity was key. In the making of his proto-electronic 1960 sci-fi record I Hear a New World, Joe Meek created imaginary worlds by recording in his bathroom and under the stairs of his home. Recording the drums for Led Zeppelin’s classic ‘When the Levee Breaks’, Jon Bonham placed his kit in the hallway of a three-storey staircase, with mics positioned at the top to catch the sound as it bounced upwards. It is the big-room reverb of Bonham’s bass drum, snare and hi-hat that give the whole track a muscular, industrial quality - the sheer imminence of a teeming flood captured in that booming drum sound. More recently, Angel Olsen has spoken about using the “reverberant” sonics of her bathroom at home to record guitar lines and vocal overdubs.

As music moved from being primarily a live experience to a recorded medium during the first half of the twentieth century, the desire to re-insert a degree of spatiality to the music influenced the development of the so-called artificial reverb. In 1947, producer Bill Putnam oversaw its first application in a commercial pop song, using a microphone and a speaker to create a DIY echo chamber in the studio bathroom to give the Harmonicats’ ‘Peg o’ my Heart’ a ghostly music hall quality.

Echo chambers subsequently became fixtures in recording studios, from Capitol’s Les Paul-designed underground chambers to the untreated attic at Hitsville USA which would in part define the Motown sound. And yet, when Phil Spector oversaw the reverb-heavy production of the Ronettes’ ‘Be My Baby’ (recorded at Gold Star Studios, also famed for its echo chambers), vocalist Ronnie Ronette made the case for the bathroom instead: "I was so shy that I'd do all my vocal rehearsals in the studio's ladies' room, because I loved the sound I got in there,” she said. “People talk about how great the echo chamber was at Gold Star, but they never heard the sound in that ladies' room.”

The thing about an echo chamber was that it was, to all intents and purposes, still just using the sound of a room to create a sonic effect. In 1957, German company EMT released what was the first plate reverb – the EMT 140 Reverberation Unit. Weighing 270 kg, it consisted of a thin, spring-mounted metal sheet, held in place by a steel frame and wooden box. A transducer at one end and a pick-up at the other, the former received the signal and set the plate vibrating, leaving the latter to record the result.

Developed at a similar time, spring reverbs worked by replacing the dense metal sheet with a set of mounted springs, which were lighter and well-suited to organ and guitar sounds to the extent that they were incorporated into Hammond organs and Fender guitar amps. So iconic have these effects become that they now carry a baked-in nostalgia, utilised among others by producer Mark Ronson on Amy Winehouse’s Back To Black. “A little bit of spring or plate reverb goes a very long way,” he said in discussing the project, conscious that Ronnie Ronette was a big idol of Amy’s too. Eerie, spacious and resonant of the materials that made it, spring and plate reverb can evoke a sense of sound emerging from the past, and an era when sound and physicality were much more intimately linked.

This relationship began to change with the development of digital reverb, also pioneered by EMT and introduced with the EMT 250 in 1976. Despite being capable of also performing chorus, phaser and delay effects, the EMT 250 was so prohibitively expensive that it encouraged cheaper alternatives to enter the market, notably the Lexicon 224, perhaps most famously used by Vangelis on his 1982 soundtrack to Ridley Scott’s Blade Runner. Academic papers have been written on reverb in Blade Runner alone, and how the use of a digital reverb in mechanising an otherwise analogue process mirrored the film’s wider themes. Depending on how it was applied, reverb could articulate the future as well as the past – a form of sonic time-travel crucial to understanding its emotional potential. That reverb is quite literally the echo of a sound departed, positions the listener not just in a physical place, but a moment in time too.

In his 1995 book Sonic Experience, Jean-François Augoyard recalls the etymological root of reverb as the Latin verb reverberare, meaning “to strike back, to reflect.” Augoyard unpicks this further, suggesting that reverberant space is perceived as “an indication of solemnity and monumentality”, something which at once indicates vast size and open space. In this context it’s not hard to see why reverb as a function of orchestral scoring has often found a fitting home in evoking the galactic emptiness of sci-fi, or the sprawling deserts of Spaghetti westerns. (It is interesting in this context too to note the otherwise unlikely parallels between the haunted tremolo guitars of rockabilly, and the space echo of dub.)

In the inherently audio-visual craft of cinema, reverb can perform the act of tying the external environment to the internal experience of the characters, creating the conditions for a heightened sense of loneliness, or a character reflecting on their place in the universe. Andrei Tarkovsky’s sci-fi epics Stalker and Solaris are as good an example of this as any.

The internality that reverb can create for a character is also pertinent to the listener, for whom the sonic space created by reverb can create room for the imagination to unfurl in unexpected ways. Writing about his childhood experiences watching Robert Bresson’s 1956 film A Man Escaped, Michael Chion remembered the prison setting as being one of large vistas and expansive space, only to find on rewatching the film as an adult that Bresson’s frame was always tightly cropped and that it was the sound – “of echoing footsteps, guards' repeated whistles and shouts” – that allowed his imagination to do the rest. It is a technique that directors who rely heavily on diegetic sound (such as Michael Haneke) employ to great effect, and which also plays a role in the sonic horror of Jonathan Glazer’s The Zone of Interest, where that which is unsaid — the emptiness after the sound — becomes too loud to ignore.

Perhaps then what makes reverb so versatile and impactful is not just the capacity to reflect spatiality or temporality, but also create space for interpretation. Chion goes on to write that “there is the degree of reverberation, which can blur the outlines of sounds.” Rather than impressing power and authority as it did in religious settings, reverb can also open a dialogue between the film and the audience, from which emotion and individual meaning can emerge. It is an experience sought by both composers and listeners alike.

Spitfire Audio's AIR Reverb — its first FX plugin, which allows users to virtually access the positioning and acoustics of the iconic Studios in Lyndhurst Hall — can be found here.