Now that I have explored the impact that effects pedals have had on guitar playing and popular music I am now going to look inside the pedal and find out a little bit about how they work.I have decided to look at the distortion and overdrive pedals.The distortion pedal emulates the sound of a tube distortion using transistors or diodes in the circuitry.Depending on the material of these diodes and their location within the pedals circuitry a different distorted sound will be produced, because these different diodes will ‘clip’ the input signal wave differently.Overdrive refers to a much more natural warm sound whereas the distortion pedal is a much harsher, rougher sound.These pedals affect the guitars input signal by adding overtones which results in a crunchier, warmer sounding guitar.The distortion effect also works by clipping the sound wave and re-shaping it into a more rigid shape with flat peaks on the sound waves.A volume boost can also be attained through these pedals.In terms of affecting the input signal these two pedals work in very different ways.
The difference between the Overdrive and Distortion pedals is the way they clip the sound wave.Overdrive pedals alter the sound using ‘soft-clipping’.Soft clipping clips the wave in a much smoother way and avoids harsher clipping which makes the sound wave become more of a square sound wave.This more rigid clipping is referred to as ‘hard-clipping’ and is used in distortion pedals.When a sound wave is clipped extra harmonics are added to the input signal and the guitar automatically sounds larger without any boost in the volume.
Overdrive
Now that I have distinguished that the Overdrive pedal gives a much softer distorted tone using soft-clipping I am going to look at the components of the pedal and how important these components are in altering the sound of the guitar.
To replicate the tube distortion of an amplifier, diodes are used in the circuitry of a pedal.When an input signal is sent through a circuit the entire signal does not come through as audible output, an amount of the signal is sent back through and loops to produce feedback.The diode in an overdrive pedal is located in this feedback loop and are therefore unable to have an immediate effect on the original signal, the effect they have is somewhat delayed and so when the sound wave is clipped the resulting peak turns out much rounder.So the location of the diode in the circuitry of the pedal is a very big factor in what kind of clipping it will undertake and what kind of distorted sound that will result in.
Distortion
Distortion pedals work by turning the input signal from the guitar into a square signal.The distortion is usually activated by a device called a ‘Schmitt trigger’; this trigger generates a square wave at the same frequency as the input of the guitar.The square wave that is generated is then mixed with the output of the amplified guitar and the ratio of these signals can be altered by the ‘DIST’ knob on the pedal.If the knob is turned full then more of the clipped signal is allowed through and the final outputted sound will be much distorted.There is also a level control on many distortion pedals and this controls the gain of the guitar and multiplies the input of the guitar to give it a boost of volume.
Since their introduction effects pedals for the guitar have become more and more popular and in modern popular music and it is now very rare for a guitarist in any genre to perform without at least one effect pedal.To help me understand effects pedals more and how they are important in shaping a bands sound I have decided to look at two case studies.Both these case studies are from different genres and are both from bands that have influenced my own guitar playing and sound.The two case studies I have decided to look into are the effects that Tom Morello (Rage Against the Machine) and Dean Glover (Hans Island) use when performing live.
Tom MorelloRage Against the Machine
Rage Against the Machine
‘Rage Against the Machine’ are a rap metal band from Los Angeles.They are a four-piece band with Brad Wilk on drums, Tim Commerford on bass, Tom Morello on lead guitar and Zak de la Rocha on vocals.They draw influence from rap, heavy metal and punk bands such as Public Enemy and the Clash they also draw great influence from artists such as Woody Guthrie and Bob Dylan that use their music to spread political protest messages.With this amalgamation of influences the band soon managed to craft their own unique sound that was made up of heavy driving guitar riffs and lyrical content that contained far left political messages.Tom Morello’s guitar playing is very distinct and by using the effects that he does he manages to create a very aggressive sound that matches the political attitude of the band and gives the band an urban sound that makes most of their songs sound like chaotic, riotous masterpieces.
This is the rig that Tom Morello used when touring in 1998.It is a typical Tom Morello set-up and has all the effects pedals that make his guitar sound so big and aggressive.He uses the onboard distortion found on the Marshall amplifier to create his loud driving guitar sound and then uses the other outboard pedals to create his more innovative strange sounds.In an interview with guitarworld.com Morello tells the interviewer of his early influences to innovate the guitar sound.When he read a Rolling Stone interview with Pete Townshend in 1982, an interview where Townshend predicted the downfall of the guitar and the rise of the keyboard in popular music, Morello’s reaction was simple; “Oh, so you think the keyboard is going to replace the guitar?Well, I’m going to make a keyboard out of my guitar”.And so came the whammy and flange that made Morello’s guitar sound like it wasn’t a guitar and allowed Tom Morello to become one of the leading innovators in Rock music.
These two effects are vital in most of the Rage Against the Machine songs.The Flanger pedal, the Ibanez DFL-10 in this case, works by producing a delayed signal that is slowed down and then released in order to catch up with the original signal.This creates a sweeping effect and has been noted by many sources to sound like a helicopter or jet plane flying overhead.Tom Morello’s use of this effect, which can be heard at the beginning of their hit single ‘Killing in the Name’, adds a sweeping sound to the song and makes it sound as though sirens or police helicopters are firing through the track.This compliments the riotous and rebellious sound and lyrics of the band.
The Whammy pedal allows Morello to shift the pitch of the guitar by moving the foot treadle forward.He uses this commonly in solo’s and also features it in the ‘Killing in the Name’ song.The Whammy makes the solo sound piercing and shifts the pitch of the guitar up to a point where it is very high pitched and sounds peculiar and almost sci-fi electronic.This is an example of Morello pushing the sound of his guitar and using his pedals to make his guitar make a sound that isn’t a conventional rock guitar sound.
Morello has also uses a tremolo effect on songs such as ‘Guerrilla Radio’.This effect is run through the amp and then bypassed using the channel switching pedal.This tremolo effect is also important in Rage’s sound, it swells the sound of the guitar and builds tension in the song before the tremolo is switched off and the loud driving guitar riff comes in.
Also included in Morello’s guitar Rig is a digital delay pedal and an equalizer.These pedals are both used much more discreetly than the other pedals.The delay pedal makes certain sections of songs, commonly solos, sound much larger and the equalizer pedal is used by Morello for its dynamics rather than its filter.Morello uses the equalizer as a sound boost pedal rather than using it to filter out certain frequencies.This sound boost helps Morello’s guitar solos stand out from the mix of the band and gives them a powerful volume boost so they take centre stage and cut through above the bass and drums when being played.
Last but not least is the Cry Baby Wah-Wah pedal that Morello has in his rig.This pedal is a classical wah-wah pedal and is one of the first of its kind to be produced, created firstly by Vox and then patented by Jim Dunlop.Morello’s use of the pedal is very innovative, not only does he use it in his solos, such as his sections of his solo playing in ‘Bullet in the Head’, but he also uses it rhythmically in the verse of ‘Guerrilla Radio’.This sound that Morello manages to produce in the ‘Guerrilla Radio’ verse very much gives the song an electronic sound and referring back to the quote where Morello aims to make a “keyboard out of (his) guitar” it seems that Morello succeeded using the guitar rig that he does and managed to make Rage Against the Machine songs much more than your conventional rock songs and managed to push them over the boundaries into the territories of heavy metal, hip-hop and funk.
Effects units are commonly used in modern guitar playing.Most of these effects are found in devices called ‘stompboxes’which allows the guitarist to turn on and bypass the effect running through their guitar by ‘stomping’ on an effects pedal in front of them.
Guitar effects pedals are emulations of studio effects that began in the mid to late 1940’s when musicians such as the famous Les Paul experimented with reel-to-reel recording tape to create tape delay effects and pioneer some very innovative guitar sounds.
The first ever stand alone effects unit was released in 1948.It was the Trem-Trol pedal released by DeArmond.This tremolo pedal pioneered the outboard effects pedal and it wasn’t long before more effects units appeared in the form of pedals, although it took until the late 50’s for the pedals to become predominant in popular use as the pedals required high voltages to work and large transformers to power them.They were also somewhat inadequate as a guitarist could find most of these early effects built into an amplifier and this was the preferred and practical way of using guitar effects.
Roger Mayer (left) with the Jimi Hendrix Experience
An important pioneer of the effects pedal was Roger Mayer.Mayer (pictured to the left with the Jimi Hendrix Experience) created the Octavia pedal in 1968; this pedal shifted the input signal one octave higher.The Fuzz box was also created by Mayor and it wasn’t long before his friend Jimmy Page started to bring this distortion sound into popular music.Jimi Hendrix also had Mayor make him a Fuzz box distortion pedal as well as the Cry Baby Wah-Wah pedal; he also used the Octavia pedal which is notable in his classic hit ‘Purple Haze’.With pioneers like Mayor creating new guitar sounds and creative guitarists such as Hendrix and Page using these sounds and broadcasting them to the masses it wasn’t long before music changed and the control guitarists had over their instruments broadened.
The ‘stompbox’ emerged itself into the life’s of classic rock guitarists such as Pete Townshend, Jimi Hendrix and Dave Davies, and their music became much more dynamic due to the increase of physical control they had over the sound their instrument was making.But by the 1980’s music began to change and digital multi-effects processors started to become more predominant in music.These digital processors allowed the guitarist to control a number of effects using just one pedal.These digital pedals overtook the ‘stompbox’ and became very popular although it soon became apparent that the analogue pedals gave a higher quality of sound and it wasn’t long before early 90’s rock bands, such as Nirvana, catapulted ‘stompboxes’ back into popular use amongst musicians.
Effects pedals can now be categorized into groups according to what they do to the sound of the guitar and how they effect the guitars input signal.These categories are:
DynamicsThese effects pedals are created to alter the volume of the guitar.Pedals such as a clean boost pedal allow the guitarist to boost the volume of his guitar without having to touch his amplifier.Another dynamics pedal is the compressor pedal which compresses the sound wave, boosting quieter signals and reducing louder signals.The tremolo effect is also considered a dynamic effect; it produces a variation in the volume of the note or chord played.Songs such as ‘How Soon Is Now?’ by The Smiths is an example of the tremolo effect in use.Roger Mayer, mentioned earlier, created a tremolo effects pedal called the Roger Mayer Voodoo Vibe.
ToneThese tonal pedals are probably the most common type of effects pedals, used in most modern rock music.They can be found in pedals which alter the tone of the guitar, most well-known pedal under this category being the distortion pedal.Distortion pedals work by adding overtones to the original tone of the guitar.This makes for a warmer sound.Many distortion pedals also have a level knob that can be changed to alter the volume at which the distortion works at.This means that the distortion pedal will not only change the tone of the sound but also the dynamics of the sound.An overdrive pedal works in a very similar way and is classed as a distortion pedal in its own right.
FilterCommon effects pedals that filter the sound of the guitar are the Equalizer pedal and the Wah-Wah pedal.The equalizer pedal works the same as other equalizers found in car stereos or home sound systems, the guitar player is able to boost certain frequencies on the pedal and the equalization will take place once the pedal is ‘stomped’.Wah-Wah pedals work in a similar way to the equalizer pedal in that it alters the frequency spectrum of the guitar although in doing this it creates vowel like sounds.This pedal is commonly found in the form of a foot treadle that can be opened and closed.This opens and closes the potentiometer and alters the threshold at which the pedal vocalizes the sound.Roger Mayer can be name checked again as his own Cry-Baby Wah-Wah pedal is one of the most popular pedals of its kind on the market.
Pitch/FrequencyThese pedals alter the pitch of the sound in different ways.Many of the pedals under this category have been inspired by classical music.The chorus effect mimics the effect used by choirs and splits the sound signal and then changes the pitch giving a very slight difference in the tone and pitch of the sound.So it somewhat allows the guitar to harmonize with itself.The vibrato effect also takes influence from classical music and makes the sound produce rapid variations in pitch to mimic the sound of a violin when the violinist sustains a single note.Other examples of pedals that alter the pitch are the pitch shifter pedal that simply transposes the notes the guitar is playing, used in ‘My Iron Lung’ by Radiohead.The flanger pedal is also worth mentioning, this pedal creates a comb filter which adds an altered delayed version of the original signal and layers the sound.
Time-BasedPedals that lie under this category include the delay pedal and the reverb pedal.The delay pedal works by duplicating the original sound with a slight time delay; this gives the sound an echo effect and makes the guitar sound larger.These delay pedals are very commonly used in guitar solos in rock music because it gives the sound a larger sound without actually boosting the volume.The reverb pedal works by creating a large number of echoes which eventually decay.Reverb is a vital post-production technique and reverb pedals have allowed guitarists to replicate the studio sound live and the ‘stomp’ of a pedal.