An acoustic one, to be exact.

In fact, if you place yourself in front of a powerful audio system, your body will start to vibrate, struck by the acoustic vibration.

It becomes music when it is used for artistic purposes.

And it gets detected by our ears.

It is measured using two methods:

• Vibrational frequency, in Hertz units (Hz)
  It will tell us the tune of said sound.
• Vibrational intensity, in deciBel units (dB)
  It will tell us its volume.

• Sounds, except for a specific one called “sinusoid” (also known as “pure sound”), are never made up of one single vibration.
• Each vibration that makes up a sound is called “frequency”, and it has its own phase.
• The sum of all these frequencies is called “spectrum”.

In fact, spectrometry gets its name from the fact that it measures the spectrum of a sound, giving information about which frequencies compose it.

For example, by the strings of a guitar. O by a drum struck with a drumstick. Or by a pipe of an organ-pipe, which vibrates thanks to a strong air stream, created by a compressor, blowing through it.

Or even by a loudspeaker crossed by an electrical signal, like a synth one, for example, which vibrates according to the signal it receives.

Through air, for starters: the body that generated the vibration hits the air molecules around it, which in turn hit other close-by particles, therefore producing a domino effect that brings the vibration to our ears.

Water, for example, transmits sounds much better than air does. In fact, when we’re underwater, everything seems much closer than it really is.

However, we are unable to hear as well as when we’re outside the water mostly because water alters the functioning of our eardrums (and, if we dive too deep, it actually damages them).

Walls are another example: they’re terrible acoustic conductors, as they greatly lower a vibration intensity (thereby softening sounds) and they suppress higher frequencies (making them more grave: the typical muffled sound that we may hear when standing outside a club.)

From our analysis, it is possible to understand that no sound has any mystery: every sound is measurable. If it’s measurable, we can analyze it.

And if we can analyze it we can understand what it is made of, and therefore recreate it to our own liking.

After all, a sound is nothing but a sum of frequencies. To reproduce it, it is sufficient to add all the frequencies it was made of. (Yes, this is the principle upon which the well-known additive synthesis lays its basis. We’ll write about it in another article.)