People had been playing electric guitar for decades before Jimi Hendrix. Mostly it had been used as a louder, less effortful version of the acoustic guitar. Jimi was one of the first to think of the guitar amp as a musical instrument unto itself, an early analog synth, with the guitar as a very sophisticated control surface.
The electric and acoustic guitar are superficially similar, but they produce sound in totally different ways. Acoustic guitars make sound from vibrations of the body, driven by the vibrating bridge, which is in turn driven by the vibrating strings. The player controls the body’s vibrations by plucking and strumming. Electric guitars generate a little sound that way too, but it’s almost inaudible. The sound you’re hearing comes from the speaker cone in the amplifier, driven by a fluctuating electric current originating in the guitar’s magnetic pickups. As the strings vibrate, they agitate the pickups’ electromagnetic field, modulating the current going through the amp and out to the speakers. Jimi Hendrix was one of the first guitarists to think of his instrument as a way to modulate an electrical signal first and foremost. Here’s his famous performance of “The Star-Spangled Banner” at Woodstock:
Jimi’s guitar is feeding back and heavily distorted. He also throws in a little wah-wah pedal. The time is free, or as the classical musicians say, rubato – drums don’t always need to keep a steady beat. Jimi interlaces the melody notes with inharmonic screams and yowls, produced by scraping the pick against the string’s winding. He throws in a few unresolved tritones at 1:35 and some terrifying divebombing sounds at 2:00. At around 2:30 he quotes part of “Taps.” This performance has been criticized as anti-American, but Jimi said in interviews that he considered himself to be patriotic.
The guitar’s strings aren’t the only way to drive the pickups. The sound from the amp can vibrate the pickups enough to produce a current that gets sent to the amp, which then vibrates the pickups harder, which sends even more current to the amp, which produces even more sound. This feedback loop builds rapidly, getting louder and louder. Every beginner electric guitarist discovers feedback accidentally by leaning their guitar against their amp without turning it off or turning the volume down. It can also be touched off by the slight hum produced by any electrical system that uses alternating current, or by radio waves – cheap, poorly shielded pickups and cables make great radio antennas. I used to live on Roosevelt Island, right across the East River from a Con Ed power plant with a whole bunch of big transformers. If I didn’t face due north while playing guitar, I picked up all kinds of radio signals and other electromagnetic noise. Nice for experimental music, not so great for producing a clean sound.
The first generations of electric guitarists considered feedback to be bad, a technical mishap to be avoided. Jimi Hendrix and his contemporaries started exploring feedback as a tool for musical expression in its own right. Feedback is more likely, and a lot louder, when the guitar is overdriven, its signal boosted and compressed to bring out and sustain overtones that are normally inaudible. Feedback has a mystical quality, an evolving life of its own. You can experience the visual equivalent by pointing a video camera at the monitor showing its own output.
You can alter the frequency of the guitar strings’ vibrations – their pitch – by pressing the strings against the frets, changing their length. You can also bend the strings, changing both their length and tension, for more nuanced pitch intervals called microtones. Jimi’s guitars have an additional pitch control, the whammy bar, which lifts the bridge, allowing very precise control of all six strings’ tension simultaneously. The whammy bar quickly pulls the strings out of tune, which is why in the video Jimi is continually adjusting the tuning pegs whenever his left hand is free.
The guitar has some ergonomic limitations, and it doesn’t give the player the same freedom to mix and match harmonic combinations as a keyboard instrument. But the guitar does give the player much tighter control over microtones. Newer synthesizers have pitch bend wheels, but they don’t give the same finesse as you can get by bending guitar strings.
The video cuts out before this point, but at Woodstock Jimi segued from “The Star Spangled Banner” into “Purple Haze.” The song is based around a distinctive chord that has come to be nicknamed the Hendrix chord.
This chord is easy to play – any beginner could learn it – but intellectually it’s extremely intense. It contains every possible interval in the western tuning system (or implies them, I count the inversions too.)
Jimi didn’t invent this chord, it had been a staple of blues and jazz since before he was born. But where Duke Ellington and Thelonious Monk used it for accents and embellishments, Hendrix pushed it front and center, using it as a cornerstone for songs like Purple Haze and Foxy Lady (in different keys than the one written here.)
All this tonal and harmonic freedom, and the guitarist’s hands and feet are still available for more music. The player’s feet can control stomp boxes and expression pedals, and the voice is free for singing and talking. The electric guitar is some seriously advanced interface design.
Here’s a remix/cover of “Purple Haze” by my band Revival Revival, combining Jimi with Missy Elliot, M.I.A. and Miles Davis. Enjoy:
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Tags: analog, cold tech hot beats, electricity, electromagnetism, electronica, feedback, guitar, harmonics, harmony, interface, jimi hendrix, music, music theory, recursion, resonance, tuning, wah pedal
Really nice analysis of Jimi’s style. It’s quite correct that he recognized the amp as an analog synth, almost a separate instrument from the guitar. His timing was very good for doing so. After a few years of guitarists like Beck and Clapton messing with the wiring bugs in 1950’s Fender amps that unintentionally caused heavy distortion, Jim Marshall came along, just in time for Jimi, and built the first amps that were meant to create a new character in the sound, not simply make it louder. In turn, Jimi’s popularity drove the development of those amps. Jimi’s employee, Roger Meyer, also made a great contribution. He built Jimi devices that no one else had, like the Octavia that created the metallic sounding false harmonics on ‘Purple Haze’ and modified wah pedals and fuzz boxes (Wah pedals were originally designed for organ, to emulate a trumpet). It was a confluence of creative forces that put Jimi in a position to do what had never been done. I can only imagine what he would have been capable of had he survived another few decades.
[...] Jimi Hendrix, Electronic Musician [...]
Great Remix!
Thanks for listening, glad you enjoyed it.
Great Column. Thanks for taking the time to help me understand how he got that sound. As I tell my young friends who extoll the virtues of the latest and greatest guitarists of this day, “yeah, but when Hendrix did it, nobody had done it before…he had to invent it before these guys could morph off of it.”