COMD 5070 exam 3 2025 Questions and
Answers
4 features of the scientific method: - --Answer --empirical, deterministic,
predictive, parsimonious
Octave - --Answer --a doubling or halving of a frequency
How many semitones in an octave? - --Answer --12. each semitone is a non-
linear step in terms of # of Hz from one semitone to the next. However, they all
sound equal to us.
Sampling rate - --Answer --The number of snapshots of the sound in time. (
in Hz) 10 samples is a 10 Hz recording. Generally, the higher the sampling rate, the
higher the fidelity of the recording. Graphic representation of the join the dots
graph, the more dots, the better the image, the fewer, the cruder. A higher
sampling rate will take up more space and require higher processing power.
Nyquist frequency - --Answer --half the sample rate. You determine the
highest frequency you want to include in your recording and double it, this will
ensure that the playback will go at least as high as the original signal. Nyquist
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,determines the highest frequency you can reproduce in playback. CD sampling rate
is 44,100 and it stores signals up to 22,050 Hz.
Aliasing - --Answer --When sampling too slowly, you will inaccurately record
the original signal. High, original frequencies will be improperly recorded as lower
frequencies. Think of the sine wave, where only certain dots were captured, so the
original waveform is "smoothed out" or aliased.
How to prevent aliasing - --Answer --This can be prevented with a low pass
filter at the nyquist frequency, to keep out the high frequencies that might be
misrepresented.
High pass filter - --Answer --allows high frequencies and attenuates low
frequencies
Low pass filter - --Answer --allows low frequencies and attenuates high
frequencies
Band Pass filter - --Answer --Removes high and low frequencies but lets
through the frequencies in the middle
Band reject filter - --Answer --Allows all frequencies except for a specific
band in the middle.
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, Fourier transform - --Answer --a way to analyze complex sounds by
separating them into their components
How to do a Fourier transform - --Answer --You take a time domain wave
form ( microphone signal - time on x and amplitude on Y) you apply the fourier
transform to it and it gives you a frequency domain wave form ( line spectrum)
which represents a slice in time that has frequency on x and amplitude on y. It's
like parsing light through a spectrum which shows all of the colors. So you can
now hear all of the individual sounds that make up the harmonic series - this is the
spectrum / frequency/domain display. Similar to a list of ingredients of a cake.
time-domain display - --Answer --has time on the X axis and Amplitude on
the Y axis and shows a waveform that represents sound directly. It shows air
pressure changes over time
Frequency-domain display - --Answer --a line spectrum that shows the
frequency components of a periodic sound(at 1 particular point in time).
Frequency is on the X axis and amplitude is on the Y.
3D spectrogram features [what are the three dimensions?] - --Answer --X
axis =time Y axis =frequency darkness =intensity
3D spectogram. what does it show? - --Answer --it's a hybrid of time and
frequency domain. Showing how the strength in each range of frequencies is
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 3
Answers
4 features of the scientific method: - --Answer --empirical, deterministic,
predictive, parsimonious
Octave - --Answer --a doubling or halving of a frequency
How many semitones in an octave? - --Answer --12. each semitone is a non-
linear step in terms of # of Hz from one semitone to the next. However, they all
sound equal to us.
Sampling rate - --Answer --The number of snapshots of the sound in time. (
in Hz) 10 samples is a 10 Hz recording. Generally, the higher the sampling rate, the
higher the fidelity of the recording. Graphic representation of the join the dots
graph, the more dots, the better the image, the fewer, the cruder. A higher
sampling rate will take up more space and require higher processing power.
Nyquist frequency - --Answer --half the sample rate. You determine the
highest frequency you want to include in your recording and double it, this will
ensure that the playback will go at least as high as the original signal. Nyquist
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,determines the highest frequency you can reproduce in playback. CD sampling rate
is 44,100 and it stores signals up to 22,050 Hz.
Aliasing - --Answer --When sampling too slowly, you will inaccurately record
the original signal. High, original frequencies will be improperly recorded as lower
frequencies. Think of the sine wave, where only certain dots were captured, so the
original waveform is "smoothed out" or aliased.
How to prevent aliasing - --Answer --This can be prevented with a low pass
filter at the nyquist frequency, to keep out the high frequencies that might be
misrepresented.
High pass filter - --Answer --allows high frequencies and attenuates low
frequencies
Low pass filter - --Answer --allows low frequencies and attenuates high
frequencies
Band Pass filter - --Answer --Removes high and low frequencies but lets
through the frequencies in the middle
Band reject filter - --Answer --Allows all frequencies except for a specific
band in the middle.
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, Fourier transform - --Answer --a way to analyze complex sounds by
separating them into their components
How to do a Fourier transform - --Answer --You take a time domain wave
form ( microphone signal - time on x and amplitude on Y) you apply the fourier
transform to it and it gives you a frequency domain wave form ( line spectrum)
which represents a slice in time that has frequency on x and amplitude on y. It's
like parsing light through a spectrum which shows all of the colors. So you can
now hear all of the individual sounds that make up the harmonic series - this is the
spectrum / frequency/domain display. Similar to a list of ingredients of a cake.
time-domain display - --Answer --has time on the X axis and Amplitude on
the Y axis and shows a waveform that represents sound directly. It shows air
pressure changes over time
Frequency-domain display - --Answer --a line spectrum that shows the
frequency components of a periodic sound(at 1 particular point in time).
Frequency is on the X axis and amplitude is on the Y.
3D spectrogram features [what are the three dimensions?] - --Answer --X
axis =time Y axis =frequency darkness =intensity
3D spectogram. what does it show? - --Answer --it's a hybrid of time and
frequency domain. Showing how the strength in each range of frequencies is
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 3
