PHYS 105 1nd Edition Lecture 19 Outline of Last Lecture I. Fourier Analysis Outline of Current Lecture II. Pitch DiscriminationIII. Pitch of Pure Tone IV. Uncertainty Principle V. Theories of Pitch: Place vs Periodicity Theory of hearingCurrent LecturePitch Discrimination- Just noticeable difference of a pure tone - The JND is the smallest change in frequency of a single sine tone that is perceptible by the average listener- Most studies place is around 3% in the 100 Hz range, but only 0.5% in the 2000 Hz range- Human ear can resolve about 1500 different pitches - JND frequency are 2 frequencies that can be separated Pitch of Pure Tone - Pitch of a pure tone depends on its intensity - If frequency is higher than 2000 Hz, higher intensity is perceived as higher pitch - If frequency is lower than 2000 Hz, the effect is reserved - Pitch and duration: o Sense of pitch could be achieved in about 2 periods o Time required to resolve a pitch is about 12-80 ms o Perceived pitch of a pure tone is dependent on pulse envelope, loudness and interfering noise Uncertainty Principle -∆ f ∆ t ≥ K-K=14 π.1- Best instrumentation that can determine the uncertainty of the frequency These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Finding the minimum time to resolve frequency Theories of Pitch: Place vs Periodicity Theory of hearing- Place Theory: Frequency is associated with a resonant area of basilar membrane - Placement Theory: Used to explain the effect of low frequency sounds masking high frequency because the low frequency sound vibrates entire cochlea membrane, while high frequency sound vibrates near oval window - Periodicity Theory: Ear performs time analysis of a sound wave o Depending on envelope of the waveform, the amplitude of the fundamental maybe small or zeroo To determine pitch, ear performs both time and frequency analysis of sound wave and then makes decision - Absolute Pitch: Absolute pitch recognition is very rare. Four theories are heredity, learning through training, unlearning by emphasis on relative pitch and imprinting at a young age - Pitch Standard: Frequency of most instruments change with temperature and humidity. Pitch rises 3 cents per degree of temperature
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