{"id":16592,"date":"2026-06-22T06:00:00","date_gmt":"2026-06-22T11:00:00","guid":{"rendered":"https:\/\/ericsiegmund.com\/fireant\/?p=16592"},"modified":"2026-05-26T16:10:35","modified_gmt":"2026-05-26T21:10:35","slug":"hammond-leslie-a-musical-power-couple","status":"publish","type":"post","link":"https:\/\/ericsiegmund.com\/fireant\/2026\/06\/22\/hammond-leslie-a-musical-power-couple\/","title":{"rendered":"Hammond & Leslie: A Musical Power Couple"},"content":{"rendered":"\n

There have been many well-known couples in the entertainment business that have brought joy to audiences. Some familiar names include Gilbert & Sullivan<\/a>, Abbott & Costello<\/a>, Martin & Lewis<\/a>, Astaire & Rogers<\/a>, Gibson & Glover<\/a>, Clapton & Stratocaster<\/a>, Lennon & McCartney<\/a>. <\/p>\n\n\n\n

I suspect that most of you recognize most of those names, and may even be devoted fans of their work. But I wonder whether any of you are fans of the duo of Hammond & Leslie?<\/p>\n\n\n\n

How about a little music trivia challenge to kick things off? Listen to this short snippet and tell me the name of the song and\/or the band to which it owes its existence.<\/p>\n\n\n\n

I’ve no doubt that you recognized that as Jon Lord’s introduction to Lazy<\/em>, from Deep Purple’s Machine Head<\/a><\/em> album, released in 1972 [1]<\/a><\/strong><\/sup>. It’s not just a great rock song, it’s also a prime example of the distinctive sounds that the combination of a Hammond organ and Leslie speakers can produce.<\/p>\n\n\n\n

I wouldn’t go so far as to say it’s a match made in heaven, unless we’re thinking of a rock and roll heaven<\/a> [2<\/a>]<\/strong><\/sup>. But there’s some pretty interesting technology at work that’s worth exploring a bit.<\/p>\n\n\n\n\n\n\n\n

But first, some history…<\/em><\/h4>\n\n\n\n

The Hammond Organ makes the scene<\/h4>\n\n\n\n

In 1934, a man named Laurens Hammond<\/a> (1895-1973) filed a patent for an “electrical musical instrument.” He, along with other inventors of the time, was interested in the idea of electronically reproducing the sound of a traditional pipe organ. His patent caught the eye of none other than Henry Ford, and Ford’s enthusiasm for the idea was the stimulus that Hammond needed to forge ahead and produce what became known as the Hammond Organ.<\/p>\n\n\n\n

It proved to be an immediate success and soon appeared first in churches and concert halls, and then in recording studios and more modest music venues across the country.<\/p>\n\n\n\n

By itself, the Hammond Organ was a versatile and popular instrument, but the appearance of another new invention took its popularity to a significant new level. That invention was the Leslie speaker.<\/p>\n\n\n\n

Along comes Leslie<\/h4>\n\n\n\n

In the late 1930s, another inventor, Donald Leslie<\/a> (1911-2004), began working on a device to allow a small instrument (like a Hammond organ) to emulate the distinctive tones of a traditional pipe organ. Those tones benefit from the spatial variation in the sound due to several factors, including the relatively wide distance between the various pipes. (If you really want to get lost in the science behind pipe organ music, knock yourself out<\/a>.)<\/p>\n\n\n\n

Leslie found the Hammond to be lacking in that area, and he had an idea for a solution…and it centered around a well-known phenomenon known as the Doppler Effect<\/a>, first described in 1842 by a scientist named \u2014 wait for it \u2014 Christian Doppler<\/a> (1803-1853). Since the Doppler Effect in sound arises when the source of that sound is moving toward or away from a stationary listener, Leslie came up with the idea of using rotating speakers to emulate the effect.<\/p>\n\n\n\n

In 1962, he patented his “Rotary Electrostatic Speaker.” As you may be able to discern from the illustration below, taken from the original patent filing, his contraption (which is unchanged in principle today) is actually comprised of two speakers, both of which can be rotated independently from each other via separate mechanisms.<\/p>\n\n\n\n

\"Illustration
An illustration that accompanied Leslie’s original patent<\/figcaption><\/figure>\n\n\n\n

The mechanics of the speaker are simple in concept. Within the wooden cabinet, there’s a built-in amplifier<\/em> (it was a 40-watt tube amplifier \u2014 aka valve amplifier<\/a><\/em> \u2014 in the early models) that connects to and receives the audio output from the instrument (e.g. organ, guitar, etc.). The audio signal is then passed to a passive crossover<\/em> which splits the audio into high and low frequencies. The traditional crossover frequency setting for the Leslie is 800 Hz (for you musicians, this frequency approximates a G# in the fifth octave, a high-pitched note in the upper midrange of a flute; middle C on a piano is 261.6 Hz). Frequencies above 800 Hz are sent to the treble unit (aka tweeter<\/em>) at the top of the cabinet, and those below that frequency are sent to the big speaker (aka woofer<\/em>) at the bottom of the enclosure. [3]<\/strong><\/a><\/sup><\/p>\n\n\n\n

Now comes the magic parts. If you view a cutaway of the Leslie speaker in operation, you might think that the tweeter and the woofer are rotating. After all, it was called a rotary speaker. But that’s not what’s happening. In reality, the tweeter is stationary but is connected to a pair of rotating horns<\/em> (only one of which is active; the other, positioned directly opposite, simply acts as a counterbalance), and the rotating horn provides the vibrato and tremolo effects for the upper range. Down below, the woofer is also stationary, but it’s sending its sound into a rotating baffle (aka drum<\/em>), usually comprised of a foam material and which provides the same effects for the lower frequencies. In addition, the speaker cabinet itself has ports in different places, giving the sounds additional spatial variation.<\/p>\n\n\n\n

Sound confusing? Here’s a gif of an operating Leslie that will clear things up.<\/p>\n\n\n\n

\"\"
Notice that the horns and baffle rotate in opposite directions.<\/figcaption><\/figure>\n\n\n\n

As I mentioned above, the Leslie speaker’s sound effects are a combination of vibrato<\/em> (a change in pitch) and tremolo<\/em> (a change in volume), both of which are the result of the Doppler Effect produced by the spinning components. [4<\/a>]<\/strong><\/sup><\/p>\n\n\n\n

Now: The sum of the parts…<\/em><\/h4>\n\n\n\n

We know that Donald Leslie designed his speaker system specifically for the Hammond organ, but when he pitched a partnership proposal to Laurens Hammond, he was immediately rebuffed. It’s reported that Hammond hated the idea<\/a>, and in fact Hammond dealers were not allowed to sell Leslie speakers. He even redesigned the output port for his organs to be incompatible with the Leslie’s connectors. Of course, this was a losing strategy of whack-a-mole, as Leslie simply redesigned his connectors.<\/p>\n\n\n\n

In any event, the combination of the two was irresistible to musicians, and the market overruled Hammond. And today, the Hammond Organ Company (now owned by the giant Suzuki Musical Instrument Corporation) advertises Leslie products on its website<\/a>.<\/p>\n\n\n\n

The musicians who employ Hammond organs, often in conjunction with Leslie speakers, make up a literal Who’s Who of the pop, rock, jazz, and blues genres. Check out this list on Wikipedia<\/a> of mostly well-known musicians who play or played Hammonds, and this YouTube playlist<\/a> of selected performances using Leslie speakers. By the way, Leslies are not used solely with organs; there’s a specific model made for guitars, and other musicians have used them with pianos [5a<\/a>]<\/strong><\/sup> \u2014 and even drums [5b<\/a>]<\/strong><\/sup>.<\/p>\n\n\n\n

One last thing…<\/h4>\n\n\n\n

We kicked off this marathon \u2014 I’m shocked and delighted that you’re still here! \u2014 with a sampling of music from Deep Purple, and I’d like to end it with another familiar example of Hammond\/Leslie product. A Whiter Shade of Pale<\/em> is perhaps Procol Harum’s most famous recording. It was recorded and released in 1967 and has since been covered by more than a thousand other artists.<\/p>\n\n\n\n

I include the song here due to its relevance to the main subjects of the post, but I’m also intrigured by the classical influences in the song. [6<\/a>]<\/sup><\/strong><\/p>\n\n\n\n

Matthew Fisher, the band’s organist (the band also feature a pianist) played a Hammond organ coupled with a Leslie speaker, and the combination is a bit less, well, frantic<\/em> than that found on the Deep Purple track we started with. Here’s a remastered video of the band’s performance.<\/p>\n\n\n\n

\n