One of the things that separate a great musician from a legendary one is the way they personalize the sound of their instrument. While much of this comes down to technique, there is a lot to be said for the impact of effects pedals. Decades ago, pedals started out as a novelty, but on today's stage, modulation pedals can be an essential part of your performance, with effects including chorus, flanging, phasing and tremolo. Modulation pedals essentially work by splitting the audio signal and manipulating each part in a different way to create effects. A chorus effect is a great example, making subtle changes to make one instrument sound like multiple instruments played together. In a similar way, ring modulator pedals are effects that add resonance to the sound, but where a chorus pedal multiplies an instrument, the ring modulator adds a bell-like, echoing effect. The flanger and phaser are similar pedals that both work by mixing a modified version of the audio signal back with the original. The results range from rippling to a Doppler effect, rounding out an otherwise flat note to give it more character. Billy Joel's "Just the Way You Are" is an outstanding example of phaser effects on a keyboard, while Heart’s Roger Fisher takes advantage of the flanger in "Barracuda." Tremolo effects pedals are not to be confused with the tremolo bar of a guitar. While they share the same name, they work differently: a tremolo bridge actually creates a vibrato by feathering the guitar strings, while a pedal introduces tremolo directly into the signal. To hear an example of an actual tremolo effect on a guitar, check out Keith Richards’ opening riff on "Gimme Shelter." Of course, as with all things music, only your ear and your personal preferences will tell you which effects are right for your instrument and playing style. It's a great idea to try out different effects pedals to see which ones work for you. With your own personalized set of pedals, you'll have a great collection of tools at your disposal.