Pitch, Loudness, Timbre Flashcards
Frequency is the
number of oscillations per time (Hz)
Amplitude is the…
highest value in cycle (m)
Waveform is the
harder! (detailed information about repeating “motif”)
Frequency is perceived as
Pitch
Amplitude is perceived as
Loudness
Waveform is perceived by
Timbre
The lowest frequency that can be produced by an instrument, or the lowest frequency present in a
sound, is called the
fundamental frequency (or first
harmonic, f0)
For a given sound, the fundamental
frequency (lowest frequency present)
dominates our perception or…
Pitch
Our ability to differentiate
frequencies is very good at
frequencies < 1,000 [Hz], but
quickly gets worse at higher
frequencies
This is quantified as the
Just Noticeable Difference
Most people can notice
frequency changes of just
1 [Hz] at frequencies up to ~
1,000 [Hz]
What are the units for amplitude?
Depends… could plot displacement
([m]) or variations in pressure ([Pa])
The energy ([J]) carried by the wave will
be proportional to the…
amplitude squared
As an example: doubling the amplitude
would quadruple the energy
Recall that power quantifies energy per time: Power is measured in Watts (W = J/s),
and for sound it will also depend upon
amplitude and frequency
Note that as sound travels away
from a source, its power will
decrease following an
inverse-
square relationship
Sound __________ is a defined as the
power per area, in W/m2, at a
receiving location
Intensity
Threshold of human hearing is
about
10 to the -12 [W/m2]
conversation is normally about
10 to the -6 [W/m2]
is the upper limit and can
cause hearing damage
10 to the 3 [W/m2]
The Sound Intensity Level (SIL) is defined
to communicate these values
SIL = 10 × log I/I 0
What are the
units for SIL?
dB
The reference sound intensity, I0, is taken as the
threshold of human hearing (10-12 [W/m2])
human perception of loudness is
strongly dependent on
Frequency
What was was developed to better
reflect human perception?
The Loudness Level, LL, measured in Phons
