PHYS 105 1nd Edition Lecture 16Outline of Last Lecture I. Antioxidant and redox regulation of gene transcription Outline of Current Lecture II. Binaural Hearing and localizationIII. Critical BandIV. MaskingCurrent LectureI. Binaural Hearing and localization- This helps us determine the direction of a sound - Localization can be explained by the shadow effect at high frequencyo At frequencies higher than 5000 Hz, the pinna aids to differentiating sounds coming from the front or back- At low frequency, diffraction is important and the shadow effect is smallII. Critical Band- Loudness = Pressure- Pitch = Frequency- Timbre = Spectrum; Envelope; Duration- 2 pure tones spaced 1 octave apart, have little overlap- 2 pure tones close in frequency might have considerable amount of overlap in the amplitude envelope on the basilar membraneo These tones are said to line in the critical bando Critical bandwidth in basilar membrane is about 1.3 mm or 1300 neurons- Complex tone that has frequencies within a critical bandwidth will have the same perceived loudness as a single tone having the same sound pressure levelIII. Masking- When ear is exposed to two or more tons, one tone can mask the other- Low frequencies always mask the high frequencyLoudness and duration: Impulsive sounds and adaptation- Sound loudness increases with increasing duration up to about 200 ms- Loudness increase by 10 dB when the duration increase by a factor of 10These 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.- Acoustic reflex:o Reflect time is about 30-40 ms o Full protection time is about 150 mso Built in function to avoid injury by very loud soundso Not effective to protect a loud
View Full Document