The perceived loudness doubles for every increase of how many decibels?

• A. 5
• B. 10
• C. 15
• D. 20

Answer: (B)

Loudness is perceived in a roughly logarithmic way with respect to sound intensity. The decibel scale reflects that: a 10 dB increase means the sound’s intensity is about 10 times greater, and our ears typically perceive that as about twice as loud. Smaller steps like 5 dB are often not perceived as a full doubling, while larger steps like 20 dB feel much louder (roughly four times as loud). So, increasing by ten decibels is the common point at which perceived loudness doubles.