SOUND WAVE

VOLUME

El volumen de un sonido indica cuánto el sonido nos llega fuerte o suave. A nivel físico, el volumen depende de cuánto es amplia la variación entre compresión y rarefacción. Si la distancia entre las partículas comprimidas es mucha y casi no se distingue de la rarefacción, entonces nuestro tímpano se mueve adelante y atrás suavemente y el sonido será percibido a bajo volumen, suave. Al contrario, si la diferencia entre compresión y rarefacción es mucha, nuestro tímpano, que es una membrana delgada y muy sensible, se mueve más energéticamente y el cerebro interpreta este estímulo como un sonido más fuerte y el volumen será alto. La unidad de medida es el decibel.

PERIOD

The period is the time it takes for a wave to pass any point, through its compression and rarefaction phases, until it returns to the same point, completing a cycle. If a wave has a short period, it means it completes its cycle very quickly, which leads us directly to the concept of frequency.

FREQUENCY

Frequency measures how many complete oscillations occur in the time of one second. A high frequency corresponds to a high-pitched sound; a low frequency corresponds to a low-pitched sound. Frequency is expressed in Hertz (Hz).

frequency (Hz) = n/sec

PHASE

Phase describes the point in the cycle where the sound wave is at a precise moment. Phase itself can be irrelevant because whether the wave starts at a moment of molecular rarefaction or compression, the sound result does not change. Rather, it becomes important when multiple waves overlap.

Two waves with the same frequency and amplitude are defined as in phase when compressions and rarefactions coincide: the effect is that they add and produce a more intense sound. But if one of the two is out of phase, meaning it starts the cycle a little later, the compression zones of one can coincide with the rarefactions of the other. If this phase shift is 180 degrees, exactly half a cycle, then the two waves cancel out: one pushes where the other pulls, and the sound is canceled.

TIMBRE

Timbre is what allows us to distinguish a note played on the piano from the same note played by a violin or sung by a human voice. Depending on the sound source, the waveform has a more or less complex and unique shape; pure waveforms like the sinusoidal are rarely found. Timbre is precisely the result of these unique waveforms which, according to Fourier’s theorem, can be decomposed into various sinusoidal waves.

GUITAR'S WAVE (4 cycles)