Chapter 5. Hearing

Front 1

Which characteristics can be used for spatial hearing?

Back 1

1. Interaural time differences
2. Interaural level differences
3. Spectral coloration

Front 2

What is the function of middle ear?

Back 2

Impedance matching between air and lymphe liquid, also protection of loud sound.

Front 3

Explain the functions of the inner ear, from the displacement of the oval window to the nerve pulse!

Back 3

Inner ear:
- from oval window to round window
- main component: cochlea (consisting of scala vestibuli, scala tympani, basilar membrane)
- function: mapping of the excitation frequencies on to different places on the basilar membrane
- frequency-place transformation: deflection of the oval window triggers a wave in the cochlea which spreads on the basilar membrane. The wave reaches a maximum for each frequency at its typical place on the basilar membrane
- organ of corti: hair cells react to a shearing movement of tectorial membrane induced through the maximum of the wave on the basilar membrane. This causes nerve impulses.

Front 4

What do we mean by the frequency-place transformation of the inner ear?

Back 4

Deflection of the oval window triggers a wave in the cochlea which spreads on the basilar membrane. The wave reaches a maximum for each frequency at its typical place on the basilar membrane

Front 5

How can we scale the height of a tone?

Back 5

1. Sound event scale of tone height (harmonic tone height scale) Equal intervals on the scale correspond to doubling of frequency (octaves, i.e. equal musical intervals). Therefore, it is a logarithmic frequency scale: m[okt]=f/f0, f0=131 Hz
2. Hearing event scale of tone height (melodic tone height scale) In this scaling method, the frequency resolution of the basilar membrane, i.e. a natural tone height scale, is modeled. Especially the mel-scale is of interest here; the tone height measured by it is referred to as ratio pitch.

Front 6

What is residual pitch?

What is repetition pitch?

Back 6

• Residual pitch: If the 1st harmonic is lacking, but the 3rd to 5th harmonic are available, - by deduction from harmonics to fundamental tone
• Repetition pitch is an unexpected sensation of tonality or pitch that often occurs in nature when a sound is reflected against a sound-reflecting surface (for example: a brick wall), and both the original and the reflected sound arrive at the ear of an observer, but with a short time delay between the two arrivals.

Front 7

What is the loudness level, and how can we measure it?

Back 7

The sound pressure level of the 1 kHz tone which is equally loud as a test tone. Measured in "phon".
To play to a person some sound and then play 1kHz sinus and ask the person to modify the loundness of sinus so it would be equally loud as given sound.

Front 8

What is loudness, and how can we measure it?

Back 8

Intensity of sound. Loudness is the subjective perception of sound pressure. How much tone A is louder as tone B.

Front 9

What is spectral masking?

Back 9

You cannot hear a test tone which is close in frequency to a masker even if it is of lower amplitude

Front 10

What is temporal masking?

Back 10

You cannot hear a test tone which is quickly following a masker.

Front 11

What is critical band?

Back 11

Critical band refers to the frequency bandwidth of the "auditory filter" created by the cochlea, the sense organ of hearing within the inner ear.
The critical band is the band of audio frequencies within which a second tone will interfere with the perception of a first tone by auditory masking.