Music & Localization

Consonance

sounds pleasant to the ear caused by increments of common fractions. The harmonic wavelengths line up in predictable ways

(2 wavelengths for every 4 of the other)

Dissonance

Sounds that are displeasing to the ear caused by harmonic wavelengths that do not match up well due to uncommon increments of fractions

(2 wavelengths for every 7 of the other)

Octaves

a series of 8 frequencies that have 2x the frequency of the one before it. It is perceived linearly but is actually exponential and physically seems to loop in on itself.

They are all harmonics but not all harmonics are them

Beat

2 slightly different wavelengths playing at the same time that merge and sound like they are getting louder and quieter in rapid succession. The frequencies are extremely close together (770 & 772 for example)

Phase

where on the wavelength you are in the sound. It is measured in degrees to describe if 2 or more wavelengths are out of sync and by how much.

In phase

the sound is amplified from perfectly overlapping wavelengths

180 degrees out of phase

the peaks of one wavelength line up with the valleys of the other to effectively cancel out the sound

Harmonics

overtones that are multiples of the fundamental

Partials

overtones that are not multiples of the fundamental or have any other relationship to the fundamental

Missing Fundamental

when the fundamental is missing, our brain functions as if it were there for the pitch but the sound gets weaker as overtones are removed

Binaural Cues

cues that require both ears and are most important for location than cues using one ear

Monaural Cues

cues that only require one ear

Time differences

binaural cue that tells us where something is from left to right based on what time the sound reaches each of our ears

Intensity differences

binaural cue that tells us where something is from left to right based on how loud and fast the sound is compared to the other ear

Intensity

monaural cue that tells us how close something is. generally, the closer it is the louder it will be

Doppler Shift

monaural cue where moving things’ sound changes based on if it is coming towards you or away from you. the sound shrinks when its coming toward you making it higher pitched and stretches as it goes away making it lower pitched

spectral content

monaural cue that tells us what kind of space where in based on the principle that higher frequencies weaken easier than lower frequencies

Echolocation in humans

ben was able to use clicks to determine what was around him and avoid obstacles after being blinded at a young age

Reverberance

the distance from a sound reflective structure through direct and indirect sound as well as time delays in echoes

Layering of Sound

we have difficulty distinguishing between similar sounds that overlap (like percussive sounds) but harmonics function to separate and organize sounds if possible

Concurrent Processes

sounds that occur at the same time and act as one such as with timbre and pitch

Sequential Processes

sounds that don’t occur at the same time but are clearly connected such as with reverberance, musical phrases, or rhythm

Segmented Processes

distinct sounds with an order that has meaning such as with vocal utterances or melodies