Distortion was at first seen as an unwelcome side-effect. Soon after the players realized that the notes could be held longer when it was distorted. Now guitars could be used to hold notes longer, just as those of other instruments. When added to a normal rhythm, this made for a much better, more interesting song.
Originally the overtaxing of the tubes in a tube amplifier caused distortion. Basically, the tubes took in more sound then they could handle without allowing the sound to break up completely. These amps are still being used because of the warm tones they create. In addition, the tubes are being used to create the same distortion sound as the original ones. Most distortions are caused by an analog amp or by a digital amplifier.
Popular Distortion Pedals: AMT Astral Tube , Artec Soloist Distortion , BOSS DS-1 , BOSS MT-2 , EHX Metal Muff with Top Boost, G2D Morpheus , Fulltone OCD , Fulltone Distortion Pro , Homebrew Full-Metal Jacket , Krank Distortus Maximus , Rocktron Rampage , SansAmp GT2 , TC Electronic Vintage Distortion , TREX Mudhoney
Equalization, otherwise known as EQ is caused by the amplification of specific frequencies within the signal. Sometimes treble or the higher pitch sounds are amplified, and other times, the bass is increased to create an interesting sound. The pitch of the sound is not changed at all, merely the quality of sound. EQ can create a vastly different sound made by a guitar or bass and can add interest to the song. You will have to experiment with EQ on different instruments of your band in order to see what works best. What sounds good when playing alone may not sound good with the whole band.
Popular EQ Pedals: AMT Guitar EQ, Artec Graphic EQ with tuner , BOSS GE-7 , EHX Knockout , TC Electronic Classic Sustain – Parametric EQ
Modulations normally sound less natural than delays, as there are not any natural analog sounds to compare them with. In this effect, certain sounds are modulated while others are left alone or modulated in another way. These are typically companied by slight delays.
Simply put, Delays split the signal into two exact copies of the same sound and play one a bit after the first, natural signal. Both signals are mixed into one output. Normally you can control the amount of the delay and the part of the signal that is held back and which is played in real-time. This control is called level control.
Popular Delay Pedals: Artec SE-ADL Analog Delay , BOSS DD-3 , BOSS DD-6 , EHX Stereo Memory Man w/ Hazarai , Homebrew Mimic , Rocktron Short Timer , TREX Replica , TC Electronic Nova Delay
Pitch shift effects are exactly what they sound like. This effect shifts the pitch up or down a specified distance. You have to be careful with this one, as a shift too far in one direction will create an entirely different note which could very well be out of key for the song played. The controls for such an effect have to be very sophisticated for just this reason.
Modeling effects are not really effects as much as a way of replicating the sounds of older guitars. They can also be used to imitate acoustic guitars or the style of a specific player that you may idolize. This type of effect is used best in recording studios. Normally in a home recording because of the lack of things like studio microphones and other expensive equipment one may need for a professional recording.
Multi-effects offer a combination of individual effects rolled into one. These tend to merge them into presets that can be used to create unique effects that you can use at a moments notice. These allow you to get more out of the effect equipment you own. Now if you own several different effects, they can be combined into completely new ones.
When you have individual pedals for specific effects can create more quality effects with a better ability to adjust the effects. Basically, putting one effect on one pedal is a better way to get more sonic quality and variations of that effect. However, a few multi-effect pedals can create some interesting effects and editing ability. Of course, deciding on creating individual or multi-effect pedal is up to the player. Personal preference reigns over choosing the effects one uses.