Sound Design Waves And Sound 4 — Questions and Answers
Question 1: What distinguishes a harmonic from an inharmonic partial?
- Harmonics are louder than inharmonic partials
- Harmonics are integer multiples of the fundamental; inharmonics are not (Correct answer)
- Harmonics only appear in digital audio
- Inharmonic partials have lower frequencies than harmonics
Correct answer: Harmonics are integer multiples of the fundamental; inharmonics are not
Harmonics are whole-number multiples of the fundamental frequency, while inharmonic partials fall at non-integer ratios, creating bell-like or percussive timbres.
Question 2: When two tones at 440 Hz and 443 Hz are played simultaneously, what audible effect occurs?
- Flanging
- Beat frequency of 3 Hz (Correct answer)
- Phaser effect
- Resonance at 883 Hz
Correct answer: Beat frequency of 3 Hz
Beat frequencies occur at the difference between two close frequencies — 443 − 440 = 3 Hz, heard as a pulsing amplitude variation three times per second.
Question 3: A material with high acoustic absorption will have which property?
- High reflection coefficient
- Low transmission loss
- High absorption coefficient close to 1.0 (Correct answer)
- High impedance mismatch with air
Correct answer: High absorption coefficient close to 1.0
An absorption coefficient near 1.0 means nearly all incident sound energy is absorbed rather than reflected, which is ideal for acoustic treatment.
Question 4: In the context of waves, what does 'superposition' mean?
- One wave blocks another from propagating
- The resultant displacement is the sum of individual wave displacements (Correct answer)
- Waves reinforce each other only at harmonics
- Two waves cannot occupy the same space
Correct answer: The resultant displacement is the sum of individual wave displacements
The principle of superposition states that when waves overlap, the net displacement at any point is the algebraic sum of the individual wave displacements.
Question 5: Which factor primarily determines the characteristic timbre of different musical instruments playing the same pitch?
- Fundamental frequency
- Amplitude envelope
- Harmonic content (overtone spectrum) (Correct answer)
- Sound pressure level
Correct answer: Harmonic content (overtone spectrum)
Timbre is shaped by the unique harmonic content — the blend of overtones above the fundamental — which differs between instruments.
Question 6: What is acoustic impedance?
- The speed at which sound travels through a medium
- The resistance a medium offers to the transmission of sound waves (Correct answer)
- The frequency at which a room resonates
- The time delay between direct sound and its first reflection
Correct answer: The resistance a medium offers to the transmission of sound waves
Acoustic impedance (Z = ρv) describes how much a medium resists sound propagation; mismatched impedances cause reflection at boundaries.
Question 7: A sawtooth wave is characterized by which harmonic content?
- Odd harmonics only
- Even harmonics only
- Both odd and even harmonics (Correct answer)
- No harmonics — only the fundamental
Correct answer: Both odd and even harmonics
A sawtooth wave contains all harmonics (odd and even) at amplitudes inversely proportional to harmonic number, giving it a bright, buzzy sound.
Sound Design Waves And Sound 4
What distinguishes a harmonic from an inharmonic partial?