Hearing and Auditory Perception: Part 3

The Human Ear

• The main function of the Pinna is to collect and direct sound waves into the ear canal.

Sound Conversion

• The cochlea is responsible for converting motion to neural activity in the human ear.
• The primary function of the cochlea is to convert acoustic energy into neural signals.

Transduction

• The eardrum performs transduction from acoustic waves to mechanical pressure waves.

Auditory Nerve

• The auditory nerve is responsible for transmitting neural signals from the cochlea to the brain.

Inner Hairs

• Inner hairs are located in the cochlea and are responsible for converting mechanical pressure waves into neural signals.

Loudness and Sound Pressure Level

• Loudness is directly proportional to the sound pressure level.
• A 10 dB increase in sound pressure level corresponds to a perceived doubling of loudness.

Threshold of Audibility

• The threshold of audibility is the minimum sound pressure level that can be detected by the human ear.

Equal-Loudness-Level Contours

• Equal-loudness-level contours represent the sound pressure levels at different frequencies that are perceived as equally loud.

Loudness and Frequency

• Low frequencies must be more intense than mid-range frequencies to be perceived equally loud.
• This is because the human ear is less sensitive to low frequencies.

Determinant of Equal-Loudness-Level Contours

• The equal-loudness-level contours are determined by the frequency response of the human ear.

Frequency Range

• The frequency range of 100Hz-6KHz is significant because it includes the majority of speech frequencies.

Pitch and Frequency

• Pitch is directly proportional to the frequency of a pure tone, but this relationship is non-linear.
• The mel scale is a non-linear frequency scale that more accurately represents the relationship between pitch and frequency.

Bandpass Filters

• It is possible to span the range of 0-20 kHz with multiple bandpass filters.

Critical Bandwidth

• A critical bandwidth of 160 Hz centered on 1 kHz maps into approximately 3.5 mels.

Masking

• Masking occurs when a sound is made inaudible by the presence of another sound that is closer to the audibility threshold.

Critical Bands

• Critical bands are important in auditory perception because they determine the frequency ranges within which sounds can be masked.

Pitch Perception

• Only sounds with a frequency above 50 Hz and below 20,000 Hz are perceived to have pitch.

Explore models and the perception side of the speech chain in the context of hearing and auditory perception. Learn how human perception plays a role in creating digital representations of speech signals. This quiz is based on a lecture from Computer Engineering Department at King Saud University.