Guitar effects come in a wide variety, however, most effects are simply variations on four basic themes: Distortion, Dynamics, Reverb/Delay, and Pitch Modulation.
Single and Multi-effects Processors
Guitar effects now come in a variety of configurations, initially, they were single effects built into pedals, called stomp boxes, which grew into multi-effects processors built into both floor pedals, rackmount, and tabletop units. Many of these units also include drum machines and headphone jacks for practice purposes.
Distortion Effects
The category of distortion has three subdivisions initially based on the sound of an overdriven tube amplifier. These include distortion, overdrive, and fuzz.
Dynamic Effects
In studio effects processing, this category includes compressors and noise gates, but for guitars, we will extend it to include gain and presence boosters, volume pedals, and tremolo and vibrato effects, which include rotating speaker effects as well. Compressors and gates are available as separate effects but are almost always built into multi-effects processors.
Reverb/Delay Effects
As the title says, this category covers special effects, including reverbs, delays, and echo effects. While these effects are built into guitar amps and come as separate rackmount units, they are also available in stomp boxes and are common in multi-effects processor. In the early days, delays used analog tape loops to produce echo effects. Now, these effects are produced digitally and with modeling techniques. An offshoot of tape-echo effects are boxes that can sample multiple layers loops and play them back in real time.
Pitch modulation Effects
This category is comprised of units that affect pitch such as flangers, phase shifters, chorus, wah pedals, pitch shifters, and has grown to include envelope and resonance filters, ring modulators, talk modulators, and has even grown into full blown synthesizers controlled by MIDI guitars.
Modeling Effects
Modeling in and of itself is not a effect but a modern way of reproducing vintage guitar effects, acoustic instruments, amplifiers, cabinets, and and even the sounds of our guitar heroes including ones they used on specific songs. Modeling primarily finds its greatest use in the studio, particularly the home project studio where a number of amp and cabinet sounds become possible in the absence of a live room, studio mics, and a wide selection of expensive vintage and modern amps and cabinets.
Stomp Box vs. Rackmount, Single or Multi-Effects
Since there are so many high quality multi-effects units available, and ranging in price up to several thousand dollars, the question arises as to whether inexpensive single-effect stomp boxes, which can be a bit noisy, are even necessary anymore. The truth is that if you look in the racks of top guitarists who can afford whatever they like, you will find combinations of stomp boxes and high-end processors. There are certain stomp pedals in varying combinations that impart a characteristic tone. This is where personal taste comes into play. You could buy the same setup as your favorite guitarist, but that might prevent you from finding your sound. There are also multi-effects processors that combine modeling and both vintage and modern effects in one convenient floor pedal that can give you the precise sounds of your guitar heroes as well as numerous options to craft your unique sound.
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