Video: A Brief History of Rotary Speakers & Pedals—From Leslie to Strymon and Beyond

Some effects transcend time. Others move throughout space. Rotary effects check both boxes. The vibe, warble, and spin of rotary effects have inspired sounds across genres, from down-home country sets to the stage of Woodstock. While rotary effects generally fit in the big bucket category of modulation sounds, they have a history all their own and relate to some iconic effects that have been cloned and reimagined in a variety of formats.

To understand the ongoing history of rotary pedals, however, means getting a sense of the effect’s bigger heritage. Much bigger.

Leslie’s Epic Organ Effect

Apart from that synth-hipster friend we all have, few normal people are thinking of plugging an organ into their pedalboard. Yet, not unlike the later Roland CE-2 Chorus geared toward keyboards but received among guitarists, the Leslie Cabinet was designed with organists in mind. It wasn’t until later that the sound was paired with the six string. So where did the idea come from and how did the item work? Meet Donald Leslie.

Donald Leslie perched upon the seat of his home organ in the 1930s pondering how to develop a sound that could match the cavernous chimes and tone of cathedral organs. If physical space was the problem, perhaps optimizing air was the solution. The feat of physics Leslie worked towards came to form in an effect as big as the organ itself, affectionately known as the Leslie Cabinet.

Picture a speaker box the size of your fridge. Inside there’s a downward-facing bass speaker within a drum. Up top are a spinning set of horns belting out the upper range frequencies. The player could then control the pace and pulse of these sounds by altering the speed of acceleration or deceleration. Where the magic happens is when these are out of sync, offering unexpected but unforgettable sounds that you not only hear but feel.

The Leslie Cabinet turned out to be a tough sell. Hammond Organs, the powerhouse brand of the day, turned down the design. Without the backing of a brand partner, Leslie went solo and founded Electro-Music. In 1941, the company released the Leslie Cabinet, which, while accepted by some organists, found unexpected acceptance with guitarists in the decades ahead. It also caught the interest of a prospective buyer.

Fender’s Biggest CBS Era Effect: The Vibratone

Fast-forward to 1965. With the fame of the Leslie Cabinet crescendoing and the music biz changing, Electro-Music found itself scooped up by the media giant CBS. While CBS didn’t do much with Electro-Music itself, they eventually channeled the idea of the Leslie Cabinet into production under the name of another company they acquired: Fender.

Since guitarists had taken to DIY mods to make the Leslie usable with the six string for some time, Fender released its own massive rotary masterpiece: the Vibratone. Though inspired by the Leslie, the Vibratone achieved its rotary sound from a different angle, literally.

"Cold Shot" - Stevie Ray Vaughan

The design was essentially an oversized guitar cabinet. In front of the speaker, however, was a styrofoam disc with holes in it. When the disc spun, sound escaped the holes in rotation, offering up a warm hypnotic tone. Though a cult classic now, the most famous use of the effect is found on the track “Cold Shot” by Stevie Ray Vaughan.

From Cabinet to Compact Pedal: The Shin-ei Uni-Vibe

Over the years, other companies have offered their take on full-form rotary speaker cabinets. More notable entries include the Maestro Rover R0-1 or Yamaha RA-50 and RA-100. But let’s face it, cabinet-based rotary units are hardly economical and ridiculous real estate hogs. If any effect was destined for a compact pedal, it’s this one.

Japanese pedal maker Shin-ei recognized this prospect in the 1960s and sought a solution in circuitry. While the magic of a Leslie was in moving air, Shin-ei developed a circuit that used photocells (think light and wires fused with fairy dust) to create an organic modulating wave effect. The result was the iconic Uni-Vibe.

The Uni-Vibe not only scaled down on the Leslie’s form factor but produced a modulation sound that spawned its own typology. While the original effect had a switch between chorus and vibrato, in reality the pedal was neither. This mislabelling, however, didn’t stall the effect’s rise to success. The most famous uses are arguably performances by Jimi Hendrix in “Machine Gun” or David Gilmour in “Breathe.”

Modern Pedal Picks for Rotary-Inspired Sounds

With Shin-ei proving that even the largest effect could be placed underfoot, both big brand and boutique pedal makers over the years have drawn upon and extended the heritage of rotary sounds.

DLS Effects' Leslie-emulating RotoSPIN. Photo via DLS Effects.

On the Leslie-esque side of things, pedal technology meant new ways of capturing and controlling the variable speeds and oscillating pulses of the speakers.

For example, the suite of Vent pedals by Neo Instruments, Strymon Lex, and Electro-Harmonix Lester pedals all allow for on the fly shifts in speeds that ramp up or rev down. These all also recreate the natural gain and compression profile of the Leslie’s preamp, giving your warble pedal a bit of gritty warmth.

The Fender Vibratone laid dormant in the company’s catalogue with few if any pedal versions until the recent release of the Fender Pinwheel. This stompbox offers some similar functionality to others on the market—speed, ramp, drive—but stands out for its tailored emulation of three different rotary effect voicings. One of them, of course, models the classic Vibratone. Spinning styrofoam wheel not included.

When it came to the classic Shin-ei design, the vibey sounds of the original resulted in both part-for-part clones and out of this world reimaginations. Arguably the most famous clone turned classic in its own right is the Fulltone Deja-Vibe, which nails the mojo of the resistance characters of the original Uni-Vibe like none other.


Modern Rotary Pedals

JHS Pedals also refined the design of the LED pulse circuit in their Unicorn pedal yet, by some mix of magic and innovation, added tap tempo functionality and sub-divisions to bring the vibe into this century.

Effects nerds will ex-communicate each other for confusing rotary speaker effects with vibe pedals. Now you know better. Yet, as with any effect debate, there’s a big backstory. In the case of rotary cabinet’s, that story looms larger than any other effect.

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