COMD 5070 EXAM 3 NEWEST 2024-2025 ACTUAL

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COMD 5070 EXAM 3 NEWEST 2024-2025 ACTUAL

EXAM COMPLETE 120 QUESTIONS AND CORRECT

DETAILED ANSWERS (VERIFIED ANSWERS)

|ALREADY GRADED A+

If there are 12 semitones between 100 Hz and 200 Hz, how many semitones would there be between 500 Hz and 4000 Hz?

• You first have to determine how many octaves there are, then

multiply by 12 to get the semitones.

• 36.

What are the three things one should know about the 12 notes between octaves?

• Each step in nonlinear.
• Each step upward is bigger than the last (about 5.9% higher in

frequency).

• No two semitones are identical; however, they sound equal in

step size.

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If one octave has 12 semitones, how many does two octaves have? Three octaves?

• 24.
• 36.

If going from 50 Hz to 100 Hz is going up by one octave, what would two octaves be? Three?

• 100 Hz to 200 Hz.
• 200 Hz to 400 Hz.

What is aliasing?When one sound is misrepresented as another.

What happens when you sample too slowly?Aliasing, it inaccurately records the original signal and you will miss what happens between samples.

When aliasing happens, what happens to higher frequencies? 2 / 3

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They will be improperly recorded as lower frequencies.

How do we prevent aliasing?Filtering before digitizing.

What filter should be used to prevent aliasing?

• Nyquist frequency.
• Frequencies above this are deleted, so they cannot contaminate

the recording.

• Most modern frequencies do this automatically.

What is a frequency domain display?

• X-axis is frequency, Y-axis is amplitude

- Spectrum display: line spectrum shows frequency components

of a periodic wave.

• Has harmonics that are multiples of the fundamental.
• Sounds are split so you can hear them individually, there is no

noise between the lines.

• Upper harmonics are weaker.
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