Roughness is best described as?

• A. Harsh sound caused by frequency interference
• B. A smooth gradual rise in amplitude
• C. A measure of sound duration
• D. A type of sound localization cue

Answer: (A)

Roughness is the perception of a harsh, gritty quality in a sound that comes from interference between nearby frequencies. When two tones with close frequencies are played together, they beat against each other, creating rapid fluctuations in amplitude. The auditory system detects these fluctuations as a shimmering, rough texture in the sound. This effect depends on the frequencies being close enough to interact within the same auditory filters, producing a noticeable beating rate that our ears perceive as roughness.

So the best description is a harsh sound caused by frequency interference. It’s not about how long a sound lasts, nor about where it’s coming from in space, nor about a smooth change in loudness over time.