pitch, loundess and timbre Flashcards
are pitch and frequency subjective or objective?
pitch is subjective, associated with periodic sounds travelling outward from a sound source
frequency is objective
what is a harmonic series?
a set of frequencies which are all integer multiples of the lowest, fundamental frequency.
eg. f1 = 200 Hz
f2 = 400 Hz
f3 = 600 Hz
….
what is special about the spectrum of a periodic vibration?
it’s a harmonic series!
a series of narrow peaks centred on a harmonic series
how does the brain identify pitch?
it searches for a pattern of harmonic frequency components.
once a harmonic series is found, a single pitch is normally identified. this pitch is the same as the fundamental pitch.
what is the basic unit of pitch? what is the frequency ratio of two tones separated by it?
the basic unit of pitch is the **octave*
two tones separated by an octave have a frequency ratio of exactly 2
what is the formula for pitch interval between two frequencies?
1200/log10(2) * log10(f1/f2)
given in cents
are loudness and acoustic pressure subjective or objective?
loudness is subjective and related to the intensity of a perceived sound
(also depends on the frequency content of the sound, as the ear is not equally sensitive to all frequencies)
acoustic pressure is objective
what is the formula for finding intensity I for an isotropic sound source of power P
I = P/4pi*r^2
what is the formula for intensity level?
IL = 10log10*( I / I(0) ) dB
where I(0) = 10^-12 W/sq m.
what is the formula for sound pressure level? (SPL)
SPL = 20log10 * ( p(RMS) / p(0) ) dB
what does each point on an N phon equal loudness contour represent?
a sine wave sound that has the same perceived loudness as a 1000 Hz tone with SPL of N dB