Definition of Sound: vibrations that travel through the air or another medium and can be heard when they reach a person’s or animal’s ear.
Definition of Audio: sound, especially when recorded, transmitted, or reproduced.
Definition of Noise: intense sounds that we may hear and interpret as uncomfortable or confusing. (perhaps measured by the difficulty of listening and/or hearing.)
Listening: to give one’s attention to a sound. (My definition: to give one’s attention to AND INTEPRET A SOUND)
Hearing: The faculty of perceiving sounds. (To identify whether or not a sound exists, or to sense it.)
When we listen to a sound, we give it meaning. The science of utilizing sounds for the sake of art comes from making sure the meaning we intend the sound to have, is interpreted as such by our audience. We may have options for interpretation, but the core of our sound should be interpreted as we intend to communicate properly.
One can make the argument that there exists music that is listened to, and music that is heard.
From physics.tutorvista.com: Properties of Sound Waves
A sound wave is defined as: A traveling wave which is an oscillation of pressure transmitted throughout a solid, liquid, or gas, composed of frequencies within the range of hearing.
Sound waves are produced through a VIBRATING OBJECT. Anything from a guitar string, to the rumble of a solid object, a speaker, to our own vocal chords.
The sound below: Is considered a transverse wave. The peak areas showcase where the particles of the sound collect most. This wave is considered a mechanical wave, meaning it needs something to bounce off of to function properly, be it air particles or something else. The vertical midpoint of every wave is considered it’s rest position. The way it would move if there was no disturbance in it.
Crest: Maximum amount of upward displacement.
Trough: Maximum amount of negative displacement.
A sound wave that travels through the air is considered a longitudinal wave. It appears like a slinky or spiral, moving back and forth, and yet towards a specific direction. Air molecules of the wave are moving parallel to the direction of the wave itself.
Amplitude: The maximum amount of displacement of a particle from its rest position. Or, the distance from midpoint to maximum. The link below calls it “rest to crest.”
Fun fact: The idea tagline “In space, no one can hear you scream.” Is not just a tagline from Ridley’s Scott’s Alien. It is technically true. Space exists in a vacuum, meaning the absence of air particles. Because nothing exists within it, you technically could not hear anything in space. The only way for you to interpret sound would be via the vibrations of another object. So, for you to hear someone, you need to A) touch that person, or B) have a special method of transmitting and receiving sound from that individual.
Frequency: How often the particles of the medium vibrate when a wave passes through the medium. Frequency is measured as the number of back and forth vibrations of a particle through a medium per unit of time. We measure this through HERTZ,( Hz) where one complete vibration in one second is equal to 1Hz.
The HUMAN EAR can hear a range of frequencies ranging from 20Hz to 20000Hz.
Differences in pitch are created via greater frequencies. We can measure volume with the following parameters:
Sound Pressure
Sound Intensity
Amplitude!
The louder the volume, the more intense the amplitude of the sound. Think of a stretching rubber band that pops under the pressure. A loud sound, (something we can call a sting in audio production) functions the same way, a method of popping the noise. Or for our ears, popping our ears.
We measure intensity in decibles(dB).
When it comes to materials, density, tension, and length will determine a different pitch, and quality of sound.
We often want to create “headroom” for our audio, so that it may rise and fall naturally, like sounds do in real life. Often time, a sound that gets too loud will cause “Clipping” a popping noise, much like the description of amplitude above. Clipping can damage audio systems and speakers, including our ears!
In this class, our safety zone for our audio will occur at -12 db.
