Sound Processing

The alteration of the characteristics of sound, in any way, is called sound processing. Techniques of sound processing are used in all cases where you want to correct a shortage, improve the sound or to create special effects. In spite of the number of the various effects, for the studio or live, the ways in which the sound can be physically modified are fairly limited. Actually the choice is whether to alter the frequency, volume, dynamics, phase (or intonation), the addition of echo, reverberation or delay. The principles of sound processing are always the same, either an electronic device is incorporated in the amplifier (more and more frequent), or the effects are treated separately, such as foot switches or studio equipment.
We will start with a basic system: guitar-cable-amplifier. Assuming that the amplifier is equiped for reverberation, we already have what we need to get the sound. At this point we must decide whether to modify the body of the sound by adding a distorter, compressor, equalizer, or digital equipment (where the signal is practically computerized, we will talk about this later). Now we will analyze the various possibilities offered by the current effects market, then try to make the most of the different equipment combinations.

The effects: typology of construction

The "older" effects are called pedal effects, because its function is obtained from pressure applied to a pedal or button. In a majority of the cases they are placed on the ground and are controlled by the feet. The principal characteristic is its extreme simplicity of use. Some pedals have become classics and have contributed in creating some famous and notable sounds.
More complete, but also more expensive, are the signal processors, better known as rack effects. Given their dimension, they are generally mounted in a support called a Flight-case, which makes it easier to transport plus protects the equipment. The signal processor, once built exclusively for professional use in a recording studio, is now used by many musicians for live performances. Surely they are not as simple as the pedals from a programming point of view, but with practice you will see some very gratifying results.
When purchasing either a pedal or a rack effect, the first thing to check is if the signal processor is analogical or digital. The obvious question is: what is the difference between an analogical effect and a digital effect? We will try to understand this important difference by citing some elements of electronics essential in understanding the operation of the equipment. As seen previously, the vibration of the string "provokes" the pick-up, which captures the sound waves produced by the movement of the string and transforms it into electric signal at low voltage. This signal is sent to the amplifier which performs the opposite task: to transform and amplify the electric signal into audio signal, which is sound.
When creating an amplification system, the effects can be inserted in two fundamental ways:
guitar - effect - amplifier;
guitar - amplifier - effect (inside the amplifier).
In the first case it is best to use analogical effects, in the second digital.