As a guitar teacher I am frequently asked a variety of questions about effects by my electric guitar students, such as; What are they? What do they do? Which ones should I get? With this article I will cover "pitch shifting" or "modulation effects."
1) "Chorus" Perhaps the most widely used modulation effect, is so called because it makes your guitar sound like more than one... thicker and usually a bit "sweeter" sounding. This is done by electronically "cloning" your original guitar sound and adding delay or "modulation" (which is shortening or lengthening the delay) to the cloned signal. Although it can be used as a solo sound, this effect is generally used for a clean rhythm sound. I think of Andy Summers (the Police) and Adrian Belew (King Crimson) when I hear this effect.
2) "Flanger" As with the chorus effect, here the signal is split or cloned and a short delay is simply added to the cloned signal, then mixed back in with your original signal. This delay has several repeats with the time of the repeats being lengthened and shortened at a steady adjustable rate. The resulting sound is usually much thicker than the chorus effect. Check out the Queen song "Keep Yourself Alive" to hear it for yourself.
3) "Phase Shifter" Once again your guitar signal is cloned... modulating the phase of the cloned signal and mixing it back with the original signal. As a result certain frequencies are cancelled all together resulting in a "swooping" or "twisted" sound. Eddie Van Halen used this effect a fair bit on his early recordings.
4) "Vibrato" With this effect the entire signal's frequency is modulated creating a slightly "out of tune" sound at a steady and adjustable rate.
5) "Tremolo" Similar to the vibrato effect where the entire signal is modulated, but this time the volume level of the guitar signal is what is effected - louder then softer, louder then softer, etc, at a steady and adjustable rate. Check out the rhythm guitar part in the Pink Floyd song "Money" for an example.
6) "Pitch Detune" Here again the original signal is cloned and the clone is electronically changed to another note all together, say a 5th of the original sound creating a "parallel" harmony. Listen to Trevor Rabin's solo in the Yes song "Owner of a Lonely Heart" to hear this effect.
Modulation effects can greatly enhance your guitar sound and are a lot of fun to experiment with. You can get all of these and more in most of the multi effects pedal boards/units that are out there like the "Boss GT8", "Digitech RP250" and the "Damage Control Glass Nexus".
Greigg Fraser is a guitarist and recording artist from Ontario, Canada who produces totally original instrumental compositions melding both clean and tortured, distorted rock guitar with fusion, new age and pop overtones.
His latest CD is entitled "Under The Radar".
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