Week 2 - Acoustics

Question 1

Spectrogram - harmonics

Answer 1

evenly spaced horizontal bars
Darkest = highest amplitude
Increase in frequency = lighter bars; shows reduction in amplitude for higher harmonics

Question 2

Spectrum vs spectrogram

Answer 2

Spectrogram - harmonics are evenly spaced horizontal lines

Spectrum - shown as vertical lines/peaks

Question 3

Sound filter

Answer 3

Software that restricts/modulates transmission of part of the frequency spectrum
Able to control frequencies present in sound

Question 4

Graphic equaliser

Answer 4

Change bass, mid, and treble of music

Question 5

Pass filtering

Answer 5

Block sound at particular points along the spectrum

low pass, high pass, bass pass

Question 6

Low pass filtering

Answer 6

Only transfers sound energy at frequencies below a certain cut off frequency

Question 7

High pass filtering

Answer 7

Allows sound energy above the cut-off

Question 8

Band pass filter

Answer 8

Transmits sound energy within a frequency range

Question 9

Band pass filter - response curve

Answer 9

Sound energy around the cut off aren’t picked up as easily; begin to decline

Question 10

Sine wave components

Answer 10

Frequency, amplitude, phase

Question 11

Use of pass filters in research

Answer 11

determines what part of the signal are important

removes unwanted frequencies

Question 12

Window of analysis

Answer 12

analysis of speech - look at a short section of the signal at a time

• fundamental frequency estimation
• intensity contour
• spectrograms

Question 13

Time-Frequency trade-off

Answer 13

inverse relationship between bandwidth and length of the window of analysis
Increased duration - reduces bandwidth, see more frequency detail
Increased bandwidth - less frequency detail, see a longer segment

Question 14

Narrow-banded filtering

Answer 14

long window of analysis; 25-30ms long

Question 15

Wide-band filtering

Answer 15

short window of analysis; 3-ms