The Leslie speaker was once a well-established piece of the furniture in many pro studios. With these mythical beasts’ swirling psychedelic spin flavouring more than just organ sounds, we list five slightly more exotic Leslie outings on record.

Demystifying The Leslie

History

The speaker was originally developed in the late 1930s, and released early the following decade to improve upon the sound of existing electric organs, including the Hammond, although the two companies were never linked. Indeed legend has it that Don Leslie and Laurens Hammond had an equal dislike of each other’s product that was only overcome by serendipity, and Leslie’s ongoing revisions to overcome Hammond’s attempts to keep third parties out.

Orientation

The units come in many different form factors, but essentially these are speaker cabinets with speaker drivers pointing into rotating objects to throw the sound. The point of doing this is to add interest and spread to electric organ sounds, although history has had other ideas, with the speaker’s churning sound catching the ear of the more adventurous artist looking for exotic flavours.

Crossing over at 800Hz on a standard unit, the lows fire downwards into a rotating drum with a scooped baffle to direct the sound, whereas the mid/treble driver faces upwards into a pair of flared horns (one of these serves only as a mechanical balance). The amp stage can be overdriven, with the extra complexity generated emphasising the rotational effect. Some amp designs are valve-powered, others are solid state.

Two switchable speeds of rotation plus a stationary (brake) position are available known as Chorale (slow) and Tremolo (fast), with many players using speed changes to punctuate their performance. Others choose to modify their units, such as directing full range audio into the bass rotor (as heard on Steppenwolf’s Born To Be Wild), or the using the ‘Memphis mod’, which sees the low rotor remaining static. Some earlier units were single speed, with a fast rotor speed. Speed changes happen much more rapidly in the highs, creating highly complex modulations when switching between them.

Clifford A. Hendrickson’s in-depth guide to the unit is a great place where Leslie nerds can find out more.

Anyone For Leslie?

The Leslie sound on organ is well known, which you can read more on here in our guide to getting sounds. Below are our five favourite examples of other sources that enjoy the unique spin of a Leslie-infusion…

Song 1 - Tomorrow Never Knows - The Beatles

It would be reasonable to assume that a studio-full of gear, unlimited time, and the creative instinct drove The Beatles towards stirring up static guitar and vocal sounds with just about anything they could get their hands on. We’re spoiled for choice when it comes to this particular band (let us know your favourites in the comments), but Tomorrow Never Knows is stark example is where John Lennon apparently sought to evoke the sound of the Dali Lama emoting from a mountain top. The result at 01:24 is instantly striking. Another worthy, but more obscure vocal instance from the band that of George Harrison on Blue Jay Way beginning at 0:47.

Song 2 - Hoodoo Man Blues - Junior Wells’ Chicago Blues Band

While many strongly associate the sound of the Leslie treatment on other instruments and voices with The Beatles, a slightly earlier example of Leslie guitar cropped up the same decade when, according to legend, Buddy Guy elected to jump into the cabinet when his regular amp failed on the session for Junior Wells’ Chicago Blues Band’s Hoodoo Man Blues. The result offers an intriguing glimpse into an alternative reality where the roughly-hewn blues sound sells out to Flower Power.

Song 3 - Teacher - Jethro Tull

British-psych-folk outfit Jethro Tull are perhaps unique for (among other things) seeing fit to throw flute into the vortex at 01:53. As with all modulation effects, Leslie works best with harmonically complex sounds, yet manages to add another dimension to the comparatively pure flute as heard on Teacher. Not content with being left out, the guitar also goes for a spin in this long-lost single from a time when references to faeries and agricultural machinery in rock music were just a normal day at the office.

Song 4 - Badge - Cream

Beginning the middle of 1960’s, George Harrison’s guitar sound, like a lot of other sounds, started to go, dare we say, a bit wobbly. Perhaps taking inspiration from Beatle peers The Beach Boys, the Leslie sound can be heard on a lot of the band’s records beginning with It’s Only Love, through Lucy In The Sky With Diamonds, and You Never Give Me Your Money. Using another descending motif with a sound that manages to sound clean yet slightly chiselled, Harrison’s cameo on Badge personifies the Leslie guitar sound at 01:06.

Song 5 - Pink Floyd - Echoes

Perhaps owing to its expressive raison d'etre, up until this record, many engineers would no sooner put a piano through a Leslie speaker than the musician put their Kaftan in a washing machine. That changed when Pink Floyd recorded Meddle, the record that saw this mainstay of Classical and beyond sent into a spin (along with just about everything else that made a noise).

The start of Echoes sees Rick Wright’s mesmerising, tremulant piano kicking off an unashamedly extended Leslie fest, with guitars and vocals also given the treatment. In an inspired piece of sound-design, the Leslie provides the perfect ethereal voice through which the piano at the start vibrates through a mystery medium. Further meanderings then begin the first movement of this proto-Dark Side outing.

Getting A Sound

Simulated Sounds

The engineer now enjoys a range of modulation audio plugins and hardware to get the sound without going the whole way, including ‘half’ cabs with real horns and simulated lows from the likes of MotionSound with both these and full-size beasts from Leslie themselves. Pedals include the excellent Neo Instruments Ventilator range, as well as unassuming stock tools such as Avid’s DB33’s ability to take an external audio input, or dedicated official recreations such as IK Multimedia’s T-RackS Leslie.

Re-amping any of these sounds can introduce some air and stereo crosstalk for extra realism.

Doing It For Real

Recording the Leslie can be a simple one-mic affair using height and/or angle to achieve the top/bottom balance, through to multi-microphone stereo glory. Working closer gives a drier, choppier sound with the converse approach available for a mellower rendering.

For naturalism, placements anywhere along 90 degree or so horizontal arc can avoid giving the impression of double-speed rotations arising from laterally opposed mics. The top and bottom rotate in opposite directions and mics can be panned accordingly.

Louvre panels and/or horn deflectors can be removed or left to control directivity in the mids and highs. Combinations of back-and side, or front-and side combinations can work well. Panels can negate wind noise from the horns. Running the unit louder than any mechanical noise (there’s plenty) also makes sense.

Although creating Leslie-style modulation from scratch is no longer really necessary, there is still a lot to be learned in Gordon Reid’s excellent guide here.

Full Circle

What are your favourite occasions where the Leslie has brought its unmistakable swirl? Let us know in the comments.