Lecture (2/8) Thursday Week 4 Thursday Flashcards
Complex wave definition
any sound that is composed of 2 or more sine waves
How do you find the points on a complex wave?
sum the instantaneous amplitudes of two or more sine waves at each point on the waveform
What is a periodic complex wave?
Complex wave that repeats itself over time
(periodic= repetitive)
Periodic complex waves are made up of…
frequencies that are harmonically related-not random
Describe the harmonic relations of periodic complex waves
each sinusoid must be an integer multiple of the lowest in the series.
The highest common denominator of a periodic complex wave sinusoid is called the
fundamental
Each of the integer multiples of a periodic complex wave is called a
harmonic
in a periodic complex wave, if f0 is 100, what are the other harmonic components?
f0 100
f2 200
f3 300
f4 400
f5 500
If the T is 8ms, what is the frequency?
8ms= .008s
1/.008s=125Hz
If 125Hz is F0 what are the next harmonics?
2f 250Hz
3f 375Hz
4f 500Hz
5f 625Hz
T/F even if F0 is not physically in a complex wave, your brain fills it in.
True
What would be the F0 if
3f 600Hz
4f 800Hz
5f 1000Hz
6f 1200Hz
200 Hz
Your brain finds the ____ of all the harmonics it hears
greatest common denominator
The pitch of the note is also the
f0
The octave is…
a doubling of frequency
What is the frequency ratio of an octave?
2:1 or 2:1
example: 200:100 or 500:250
What is consonance?
adding frequencies that are harmonically related
What is dissonance?
adding frequencies that are not harmonically related
What happens when you combine frequencies that are close
it creates complex waves that wax and wane in amplitude (beats)
Changes in amplitude cause ______
beats
The number of beats per second is equal to the _____
difference in Hz between the two tones
What is the definition of a Fourier Analysis?
Mathematical process by which a complex sound is broken down into its individual sine waves
(frequency on the x axis and power on the y axis)
What does an aperiodic complex wave represent?
combinations of sounds that are not harmonically related
characteristics of continuous aperiodic waves
-on going in time
-noise
characteristics of transients aperiodic waves
-short duration; brief acoustic event
-click
the ______ the click, the _______ the spectrum
shorter the click, broader the spectrum
What has more frequencies?
P= 1ms or
P=.03ms
P=.03ms
-because it is a shorter period, so it has more frequencies within in
What is the psychological definition of noise?
unwanted sounds
Which noise has all frequencies of equal amplitude?
white noise
Describe gaussian noise
-a type white noise with random amplitudes
-amplitudes vary according to a bell curve
What frequency emphasis is Sawtooth noise?
high frequency emphasis
What frequency emphasis is Pink noise?
low frequency emphasis
What is the definition of frequency distortion?
frequencies or amplitudes in the output that were not in the input
What will introduce distortion?
a transfer function of energy from one form to another
energy transfer is _____
nonlinear (causes distortion)
The ear is _____
nonlinaer
In distortion, _______ are the frequencies that are added
harmonics
Otoacoustic emissions
used to test newborn hearing
Tones that are the result of summanation
f1 + f2 ; 2F1+f2
Tones that are the result of difference
f1-f2 2f1- 2f2
Distortion is measured in
Percentage
