Sound is a phenomenon that implies a propagation of waves generally produced by a vibratory movement of a body. The propagation of sound implies a transport of energy without carrying out a transport of matter.
As the sound is produced by a wave movement when applying the Fourier transform we can express it by a sum of sinusoidal curves that correspond to pure tones that can be characterized by the magnitudes of any wave such as:
-Period It is the time elapsed between two equivalent points of a wave.
– Wavelength It is the real distance a wave travels from its highest point to the next equivalent point.
-Frequency It is the magnitude that measures the number of repetitions in a space of time.
-Amplitude It is the distance between the furthest point of the wave with the equilibrium point.
These magnitudes give the sound a series of characteristics such as:
-Duration: Determines the length or short of the sound due to the time, measured in seconds, it occupies.
-Intensity: Determines the high or low sound due to what we know in relative terms as volume, which is measured in decibels (it is a logarithmic scale).
-Timbre: Determines the proper nuance of each instrument or sound source due to the different harmonics that compose it.
– Hue: Determines the acute or serious sound due to the frequency it has. The frequency is measured in hertz (Hz).
If we carefully consider it, we will see that the initial concept of Mp3Gain was intensity, which is measured in decibels and represents the loudness we perceive.
Digital audio
Digital audio is the digital coding of an electrical signal that represents any sound wave. This electrical signal is picked up for example by a microphone, which takes the sound whose nature is analog and transforms it into electricity that still has the same type of analog nature, then through the necessary hardware and software it can be transformed into binary information, turning Something continuous in discreet. This process involves two tasks: sampling and digital quantification of the electrical signal.
Within the digital audio there are different types of formats to represent the audio:
-PCM: They contain all the information received from the analog to digital converter, without any omission of data. This makes the type of formats that have the best quality in the digital world. WAV is an example of this type of format in question.
-Compressed: It is similar to the previous one, but specific compression techniques are used in which “non-essential” information can be lost to reduce the size of the final file. They usually have good quality in relation to the weight of the file, but as noted above, information is lost, so those with sufficiently developed / trained ears might perceive that there is something strange in a song for example. On the one hand we have formats such as MP3 and OGG that compress with loss, compared to FLAC that compresses without loss. Obviously between one format and the other there is a notable difference in the size of the final file.
-Descriptive: They are used primarily to make music and contain mainly a description of what would be the “score” of the song. With this description, the algorithm, which reproduces the song, can take a sound source with samples of the instruments that the composition needs, to synthesize the final sound based on the indications of the “score”. Examples of this format are MIDI and tracker formats (MOD, XM, IT, etc.). The difference between MIDI and tracker formats is that the latter bring built-in sound sources into the file, so the final file weighs more than using MIDI. However, with MIDI we will need to obtain a sound source on our own or use the one that brings the default sound card (which is not usually too good).
