Module 1

We live in a world full of sounds. From the sound of an alarm clock, the voices of other people, the calls of animals, or the rumble of an approaching thunderstorm, the sounds we hear can be very different.

Scientists have studied the way we hear and perceive sound. Sound itself is made up of waves that travel through the air, much like waves traveling through the ocean. Our ears sense these waves and turn them into signals that are received by the brain. The reason we hear differences in sounds, is because each sound has different attributes .

Sound has four key attributes:

  1. Loudness. Some sounds are soft and others are loud. Loudness, sometimes called volume, is our perception of the softness or loudness of a sound. In music, sounds that are soft are piano or p (Italian for soft) and sounds that are loud are called forte or f (Italian for loud). Sometimes sounds are in between soft and loud. The term mezzo (Italian for medium) is used in conjunction with piano and forte to describe sounds that are medium soft (mezzo piano or mp) and medium loud (mezzo forte or mf). Sounds that are louder have a bigger waveform than sounds that are softer. In physics, the measurement for the height of a sound wave is amplitude.

  2. Pitch. Some sounds are low and others are high. Pitch is our perception of low or high sounds. For example, the rumble of thunder or the sound of a tuba are low sounds. High sounds would be birds chirping or the sound of a piccolo. Sounds that are higher have shorter wavelengths than sounds that are lower. In physics, the measurement of the length of a waveform is referred to as its frequency.

  3. Duration. Some sounds last for a long time while others last only a short time. Duration is how long a sound lasts and is usually measured in seconds or beats. Short sounds are things like snapping one's fingers or a single hit on a snare drum. Other sounds can last for a while, like the hum of a car engine or a hit on a gong. The organization of durations in time is called rhythm.

  4. Tone Color. Two sounds may be equally loud, at the same pitch, and have the same duration but they can still be different from each other. For example, a flute playing the A above Middle C at mezzo forte for 4 seconds sounds different from and a trumpet sounding the A above middle C at mezzo forte for 4 seconds. The instruments sound different from each other because they have different spectra or timbre (pronounced “Tam burr”, like the first two syllables of “tambourine”).