The tones that are separated by three octaves have a frequency ratio of

$A$ group of people watch an ice show held in a closed area. Skaters perform a music show whose sound level is $60 \ dB$. $A$ spectator can yell at $40.0 \ dB$. Which one of them represents the approximate combined sound level (in $dB$)?

Decibel is the unit of

Quality of a musical note depends on

The intensity of sound during the festival season increased by $100$ times. This could imply a decibel $(dB)$ level rise from

The power of sound from the speaker of a radio is $20 \text{ mW}$. By turning the knob of the volume control,the power of the sound is increased to $200 \text{ mW}$. The power increase in decibels as compared to the original power is $.... \text{ dB}$.