LECTURE 10 NOTES MUSIC AND SPEECH
Explain the temporal code of sound frequency. What is coded? How is it coded?
Vibrations from the sound pressure wave. Mechanically stimulate the organ of corti. through vibrations of the tectorial membrance
induces shearing of the hair cells. Hair cells are brushed in one or several directions. Depending on the direction , hair cells will
response and stimulate the AN fibers.
Shearing of neuron in one dire casues teh neuron to fire AP’s but shearing in other dire doesnot .s o when it is sheared in that dire, it
fires bursts of AP’s and then slows down till it is sheared again in its desired direction that its most responsive to.
Lots of action potential and then dies off.repeats this pattern.
When u look at the pattern of this neuron, this signal of intermittent bursts carries information of the frequency.
~ looking at a single hair cells tells the brain about the frequency.
But only up to certain point up to 1000Hz because hair cells cannot fire much faster than that.
The neuron has to build up its resting potential.
Another problem: neurons can only be so much accurate
Whats the difference between the tone height and tone chroma?
Music is distinctive characteristic of humans. Animals don’t have music
What is music for?
Potential reasons: music is associated with emotions. It might express or amplify our emotions.
Music used in therapies.
Pythogaras: if u dissect a string at systematic intervals, u get certain increases in tones that sound good.
Octave: very regular relationship of 1:2
Music in avery specific range, 25- 4500 Hz not much higher than that.
That is much less what we can actually hear.
Regular increment of pitch is logarithmic.
Therefore, pitch is not directly related to frequency.
Piano has the widest range of frequencies.
Most of these instruments hover and cluster in narrow frequency range.
These C’s sound much more similar to each other than E3 even though E3 is much more closer in frequency to C3.
People are more likely to mistake C3 and C4 than C3 and E3.
Pitch is related to frequency in a l