A wah-wah pedal (or simply wah pedal) is a type of electric guitar effects pedal that alters the tone and frequencies of the guitar signal to create a distinctive sound, mimicking the human voice saying the onomatopoeic name "wah-wah". The pedal sweeps the peak response of a frequency filter up and down in frequency to create the sound, a spectral glide, also known as "the wah effect". The wah-wah effect originated in the 1920s, with trumpet or trombone players finding they could produce an expressive crying tone by moving a mute in and out of the instrument's bell. This was later simulated with electronic circuitry for the electric guitar when the wah-wah pedal was invented. It is controlled by movement of the player's foot on a rocking pedal connected to a potentiometer. Wah-wah effects are used when a guitarist is soloing, or creating a "wacka-wacka" funk-styled rhythm for rhythm guitar playing.
The first wah pedal was created by Bradley J. Plunkett at Warwick Electronics Inc./Thomas Organ Company in November 1966. This pedal is the original prototype made from a transistorized MRB (mid-range boost) potentiometer bread-boarded circuit and the housing of a Vox Continental Organ volume pedal. The concept, however, was not new. Country guitar virtuoso Chet Atkins had used a similar, self-designed device on his late 1950s recordings of "Hot Toddy" and "Slinkey". Jazz guitarist Peter Van Wood had a modified Hammond organ expression pedal; he recorded in 1955 a version of George Gershwin's "Summertime" with a "crying" tone, and other recordings including humorous "novelty" effects. A DeArmond Tone and Volume pedal was used in the early 1960s by Big Jim Sullivan, notably in some Krew Cats instrumental tracks, and in Dave Berry's song "The Crying Game".
The creation of the modern wah pedal was actually an accident which stemmed from the redesign of the Vox Super Beatle guitar amplifier in 1966. Warwick Electronics Inc. also owned Thomas Organ Company and had earlier entered into an agreement with Jennings Musical Instruments of England for Thomas to distribute the Vox name and products in the United States. In addition to distributing the British-made Vox amplifiers, the Thomas Organ Company also designed and manufactured much of the Vox equipment sold in the US (the more highly regarded British Vox amplifiers were made by Jennings (JMI), the parent company of Vox and designed by Dick Denney). Warwick assigned Thomas Organ Company to create a new product line of solid state Vox amplifiers (called Vox Amplifonic Orchestra), which included the Super Beatle amplifier, named to capitalize on the Vox brand name's popularity in association with the Beatles, who used the Jennings-made English Vox amplifiers such as the famous Vox AC30 (although the Beatles did use several American-made Super Beatle units on their 1966 US tour). The US-made Vox product line development was headed by musician and bandleader Bill Page. While creating the Vox Amplifonic Orchestra, the Thomas Organ Company decided to create an American-made equivalent of the British Vox amplifier but that was transistorized (using solid state circuits), rather than vacuum tube, which would be less expensive to manufacture. During the re-design of the USA Vox amplifier, Stan Cuttler, head engineer of Thomas Organ Company, assigned Brad Plunkett, a junior electronics engineer, to replace the expensive Jennings 3-position MRB circuit switch with a transistorized solid state MRB circuit.
Plunkett had lifted and bread-boarded a transistorized tone-circuit from the Thomas Organ (an electric solid state transistorized organ) to duplicate the Jennings 3-position circuit. After adjusting and testing the amplifier with an electronic oscillator and oscilloscope, Plunkett connected the output to the speaker and tested the circuit audibly. At that point, several engineers and technical consultants, including Bill Page and Del Casher, noticed the sound effect caused by the circuit. Page insisted on testing this bread-boarded circuit while he played his saxophone through an amplifier. John Glennon, an assistant junior electronics engineer with the Thomas Organ Company, was summoned to bring a volume control pedal which was used in the Vox Continental Organ so that the transistorized MRB potentiometer bread-boarded circuit could be installed in the pedal's housing. After the installation, Page began playing his saxophone through the pedal and had asked Joe Banaron, CEO of Warwick Electronics Inc./Thomas Organ Company, to listen to the effect. At this point the first electric guitar was plugged into the prototype wah pedal by guitarist Del Casher who suggested to Joe Banaron that this was a guitar effects pedal rather than a wind instrument effects pedal. Banaron, being a fan of the big band style of music, was interested in marketing the wah pedal for wind instruments as suggested by Page rather than for the electric guitar as suggested by Casher. After a remark by Casher to Banaron regarding the Harmon mute style of trumpet playing in the famous recording of "Sugar Blues" from the 1930s, Banaron decided to market the wah-wah pedal using Clyde McCoy's name for endorsement.
After the initial invention of the wah pedal, the prototype pedal was then modified by Casher and Plunkett to better accommodate the harmonic qualities of the electric guitar. However, since Vox had no intention of marketing the wah pedal for electric guitar players, the prototype wah-wah pedal was given to Del Casher for performances at Vox press conferences and film scores for Universal Pictures. The un-modified version of the Vox wah pedal was released to the public in February 1967 with an image of Clyde McCoy on the bottom of the pedal.
Warwick Electronics Inc. assigned Lester L. Kushner, an engineer with the Thomas Organ Company, and Brad Plunkett to write and submit the documentation for the wah-wah pedal patent. The patent application was submitted on February 24, 1967 which included technical diagrams of the pedal being connected to a four-stringed "guitar" (as noted from the "Description of the Preferred Embodiment"). Warwick Electronics Inc. was granted US patent 3530224 ("foot-controlled continuously variable preference circuit for musical instruments") on September 22, 1970.
Early versions of the Clyde McCoy featured an image of McCoy on the bottom panel, which soon gave way to only his signature. Thomas Organ then wanted the effect branded as their own for the American market, changing it to Cry Baby which was sold in parallel to the Italian Vox V846. Thomas Organ's failure to trademark the Cry Baby name soon led to the market being flooded with Cry Baby imitations from various parts of the world, including Italy, where all of the original Vox and Cry Babys were made. Jen, who had been responsible for the manufacture of Thomas Organ and Vox wah pedals, also made rebranded pedals for companies such as Fender and Gretsch and under their own Jen brand. When Thomas Organ moved production completely to Sepulveda, California and Chicago, Illinois these Italian models continued to be made and are among the more collectible wah pedals today.
Some of the most famous electric guitarists of the day were keen to adopt the wah-wah pedal soon after its release. Among the very first recordings released featuring wah-wah pedal were "Tales of Brave Ulysses" by Cream with Eric Clapton on guitar and "Burning of the Midnight Lamp" by the Jimi Hendrix Experience, both released in 1967. Hendrix also used wah wah on his famous song Voodoo Chile, in intro and in soloing. Clapton, in particular, used the device on many of the Cream songs included on their second and third albums, Disraeli Gears (1967) and Wheels of Fire (1968) respectively. In fact, Clapton himself would subsequently employ it again on "Wah-Wah", from his good friend George Harrison's solo album All Things Must Pass, upon the dissolution of The Beatles in 1970. Another prominent use occurred in the recording of "Crimson and Clover" by Tommy James and the Shondells in late 1968, with the single version eventually reaching number one in early 1969. Terry Kath, lead guitarist for the band Chicago, used it on many of their early recordings as well. Martin Barre, lead guitarist for the fledgling Jethro Tull, also employed it to great effect on their second album Stand Up, particularly on "We Used to Know" and "Look into the Sun". Yet another famous guitarist, Jimmy Page, featured the wah-wah pedal on several songs from the final Yardbirds album Little Games, as well as the solo on the Led Zeppelin song "Custard Pie", and throughout "Trampled Under Foot", both from Physical Graffiti. Tony Iommi has also used it on quite a few Black Sabbath recordings; notably the songs "Black Sabbath", "The Wizard" and "N.I.B." from their self-titled debut album, "Electric Funeral" from Paranoid and "Supernaut" from their fourth album. He also employed it on later recordings, such as "Shock Wave" on Never Say Die! (1978), "Lady Evil" from the first Ronnie James Dio-era album Heaven and Hell (1980), and "Turn Up the Night" on the subsequent Mob Rules (1981).
In addition to rocking the pedal up and down to crest a spectral glide, another function of the pedal is to use it in a fixed position. A guitarist using the wah in this way selects a position on the wah pedal and leaves the pedal there. Depending on the position of the pedal, this will boost or cut a specific frequency. This can be used for emphasizing the "sweet spot" in the tonal spectrum of a particular instrument. One electric guitar player to use the pedal in this way was Jimi Hendrix, who revolutionized its application by combining a Fender Stratocaster with stacked Marshall Amplifiers (in both static and modulated mode) for lead and rhythm guitar applications unheard of before then. According to Del Casher, Hendrix learned about the pedal from Frank Zappa, another well-known early user. Milestones of this signature guitar and amplifier combination include songs such as "Voodoo Chile (Slight Return)" as well as the "Star Spangled Banner" which was played by Hendrix at Woodstock in 1969. Mick Ronson used a Cry Baby for the same purpose while recording The Rise and Fall of Ziggy Stardust and the Spiders from Mars.
Another famous style of wah-wah playing is utilizing it for a percussive "wacka-wacka" effect during rhythm guitar parts. This is done by muting strings, holding down a chord and moving the pedal at the same time. This was first heard on the song "Little Miss Lover" (1967) by the Jimi Hendrix Experience. One of the most famous uses of this effect is heard on Isaac Hayes's "Theme from Shaft" (1971), Charles Pitts playing the guitar. Michael Schenker also utilized the pedal in his work. The "wah-wah" and "wacka-wacka" effects are often associated with the bands on 1970s TV variety shows, like those of Sonny and Cher, Flip Wilson, or Donny and Marie Osmond; or with the soundtracks of pornographic films, the sound referenced in TV commercials for Axe (brand) body spray as "bow chicka wow wow."
David Gilmour (Pink Floyd) used the pedal to create the "whale" effect during Echoes. He discovered this effect as a result of a roadie accidentally plugging his guitar into the output of the pedal and the input being plugged into his amp. The effect was first used during live performances of The Embryo during 1970 but was then switched into Echoes as it was being developed before being released on the Meddle album on 31 October 1971.
Many bassists have also used the wah-wah effect, for example Michael Henderson on Miles Davis's album On the Corner (1972). Bassist Cliff Burton of Metallica used a Morley Wah pedal (along with a Big Muff Distortion) extensively, including on "(Anesthesia) Pulling Teeth", which is primarily a bass solo recorded for Kill 'Em All (1983), and "The Call of Ktulu" and "For Whom the Bell Tolls", both recorded for Ride the Lightning. Geezer Butler, bassist of Black Sabbath, used it when playing his solo "Bassically", along with the bass line in "N.I.B.". Chris Squire of Yes used a wah-wah pedal on his solo piece "The Fish" on the album Fragile. While wah pedals are less popular as a bass effect, various companies now offer pedals designed specifically for bass guitars.
Melvin Ragin, better known by the nickname Wah Wah Watson, was a member of the Motown Records studio band, The Funk Brothers, where he recorded with artists such as The Temptations, The Jackson 5, The Four Tops, Gladys Knight & The Pips, and The Supremes. He played on numerous sessions in the 1970s and 1980s for many top soul, funk and disco acts, including Herbie Hancock.
Keyboardists have also made use of the wah-wah effect both in the studio and during live performances. Garth Hudson famously used a wah-wah pedal on a clavinet in The Band's song "Up on Cripple Creek" to emulate a jaw harp. Rick Wright of Pink Floyd played a Wurlitzer electric piano through a wah-wah pedal in their song "Money" to give the impression of many consecutive chords being played. Jordan Rudess of Dream Theater made an extensive use of the wah-wah pedal on Dream Theater's album Train of Thought. John Medeski of Medeski, Martin, and Wood uses a wah pedal with his clavinet.
Many jazz fusion records feature wind and brass instruments with the effect - Miles Davis's trumpet being a well-known example. Davis first used this technique in 1970 (at concerts documented on Live-Evil and The Cellar Door Sessions) at a time when he also made his keyboard players (Keith Jarrett and Chick Corea) play electric pianos with a wah-wah pedal. Napoleon Murphy Brock played a saxophone amplified through a wah-wah pedal in the Frank Zappa movie The Dub Room Special, as well as on some of Zappa's albums. David Sanborn can be heard playing an alto saxophone modified by a wah-wah pedal on the David Bowie album Young Americans. Noted saxophonist King Curtis was also known to use a wah-wah pedal. Dick Sims, the keyboard player with Eric Clapton in the late 1970s, used a Hammond organ in conjunction with a wah-wah pedal, placed on top of the organ and operated by his palm.
The effect is also extensively used with the electric violin. Notable examples are Jerry Goodman with the Mahavishnu Orchestra, and Jean-Luc Ponty, Don "Sugarcane" Harris and Shankar with Frank Zappa, all usually engaged in long wah-wah violin/guitar duels. Boyd Tinsley of the Dave Matthews Band is known to use a wah-wah pedal live.