Sound Terminology

Sound Waves: molecular movement (air) at 1,130 ft. per second in all directions.
Compression wave
Phasing: Diagram of sound pressure movement
Frequency: number of peaks (cycles) in a given distance (time).
    100 cycles (waves per second + 1 Hertz
    Rate of peaks per second changes pitch of sound
    More Hertz (Hz) = higher pitch

Amplitude: intensity of frequency, volume
    Change in height of peaks (number of cycles per second remains the same)
    Volume measured in decibels (dB).
    More dB = more volume.
    0 dB is arbitrarily set at the threshold of hearing

Inverse Square Law: volume drops at the square of the distance from source

 Harmonics: equal division of cycles
Middle C = 256 Hz
1 octave above middle C = 512 Hz

In and out of Phase: Multiple sound sources in combination

Doppler Effect: sound approaching increases in pitch
Sound waves are compressed creating the illusion of more cycles per second.

The Human Ear

Discernment: ears are located on the sides of human heads.
Horizontal discernment: 15 degrees
Vertical discernment: 45 degrees

Dynamic Range

Envelope: Shape of sound as defined by how it begins, changes interally over time, and how it ends.
    Attack
    Internal dynamics
    Decay

Reverberation: Time of decay 60 dB (1 millionth of original sound)
Reflectance
Absorption
Directionality of various pitches (higher frequencies are more directional)