ELECTRIC GUITAR FX

Electric Guitar FX

Guitar FXs come in the form, of stompboxes, which are individual effects units in the form of floor-mounted boxes, activated by stomping on a switch.

Stompboxes were the original guitar effects units and, despite the introduction of multi-effects units in the late 1980s and early 90s, have retained much popularity amongst guitarists for their greater flexibility in routing and editing.

Electric Guitar FX - Types

• Distortion

• Guitar amp simulators

• Wah Wah

• Vibrato & Tremolo

• Modulation using tape recorders

• The Leslie Cabinet / Rotary Speaker

Electric Guitar FX - Distortion

• Originally achieved by overloading the circuitry at some point in the signal chain. When the gain is increased, the peaks and troughs of the waveform are clipped, and the distorted signal has more harmonics.

• Later distortion FXs were incorporated into guitar amps, or as stompboxes

• Distortion FXs are also used in as DAW plug-ins, sometimes emulating other hardware

• Valve amps were used almost exclusively until late 60s/ early 70s when solid-state amps began being used

• Solid-state amps used transistors in their construction rather than valves

• Transistors were cheaper, smaller and more reliable

• Made amps more efficient, which had an impact on their affordability and size.

• Valve amps however soft clip a signal giving a warmer overdrive, whilst Solid-State exhibits hard clipping wish is much harsher.

Electric Guitar FX - Types of Distortion

• Overdrive

• Distortion

• Fuzz

Electric Guitar FX - Types of Distortion - Overdrive

• Term commonly used to describe a form of distortion that is smoother than fuzz and is often used for chordal passages and riffs

• Often the 'crunch’ setting on amps, giving ‘grit’ and more ‘guts’

• Often used for blues rhythm guitar and, at higher gain setting, lead guitar work.

Electric Guitar FX - Types of Distortion - Distortion

• As well as being the generic term for all three effects, distortion is an FX in its own right

• Used in heavy rock and metal and for lead guitar work

• Usually has a higher gain setting then overdrive, making it less suitable for full chords, but very suitable for heavy power-chord riffs

• Generic ‘scooped’ EQ (where the bass and treble are boosted while mids are cut) guitar sound of American metal bands is one of the more famous distorted sounds, used by bands such as Metallica and DragonForce.

Electric Guitar FX - Types of Distortion - Fuzz

• Fuzz was made famous by Jimi Hendrix and his use of the ‘Fuzz Face’ Pedal

• Has a raw edge to it and works better with solo lines than with chords because simultaneously sounding notes all interfere with each other, merging in a dissonant fashion.

Electric Guitar FX - Distortion Parameters

• Gain - The drive, giving the amount of distortion

• Output - Volume of the output signal (after distortion) to compensate for the increase in gain necessary to achieve distortion. This also allows you to balance the volume of the distorted and clean signals if switching between the two.

• Tone - Controls the cutoff frequency of a low pass filter

Electric Guitar FX - Guitar Amp Simulators

• Amp simulators can be used to emulate different guitar and amp sounds and the effects that go with it such as spring reverb and tremolo

• Possible to DI a guitar and simulate the sound of it going through an amplifier and miked up speaker cabinet.

Electric Guitar FX - Wah Wah

• Commonly used in funk music and to make guitar solos sound more interesting. The effect sounds like its name

• Created by sweeping the centre frequency of a band pass filter

Electric Guitar FX - Vibrato & Tremolo

Other modulation FX combine wet and dry signals but these two consist only of the signal to which the effect has been applied

• Vibrato modulates the pitch of the signal, using an LFO

• Sounds like the natural vibrato created by vocalists, or a guitarist moving their finger on the fretboard.

• Tremolo modulates the volume of the signal using an LFO

• Sounds like the note is fading in and out periodically

Historically, modulation effects would have been created using tape machines or rotary speakers.

Electric Guitar FX - Modulation using Tape Recorders

• The recording would be duplicated and played simultaneously on two tape machines

• Hand pressure was applied to the supply reel of one of the tape recorders which slowed it down slightly. This created a slight delay, along with a variation in pitch

• When combined the signals from both tape recorders crated a ‘flange’-like modulation effect.

Electric Guitar FX - Leslie Cabinet / Rotary Speaker

• Contains a rotating horn, with two modes:

  • Tremolo (faster)

  • Choral (Slower)

• This creates a slight shift in pitch and changes in volume and tone as the speaker spins, creating modulation.

• In physics this is called the Doppler Effect

• Leslie Cabinet was commonly used with the Hammond organ, and is often reproduced in the form of ‘rotary’ software plug-ins