Measured independently at the position of a receiver, two speakers are measured to have sound levels of 61.4 dB and 63.8 dB, respectively. When both speakers emit sound simultaneously, what sound level is detected?

Two sound waves arrive to an observer, the first is loud at 2 W/m ^2 and the second one is quieter at 100 mW/m^2 ; how many dB louder is the first one compared to the second one?

The sound level measured in a room by a person watching a movie on a home theater system varies from  50 dB  during a quiet part to  90 dB  during a loud part. Approximately how many times louder is the latter sound?

A sound wave radiates from a speaker in all directions. If the power of the sound source is 250 W, calculate the intensity level in dB of the sound wave 0.4 km from the speaker. Hint: Presume that the sound waves spread as a sphere (not a hemisphere).

A 60 year old person has a threshold of hearing at f=10 kHz of 79.0 dB. In contrast, a typical young adult's threshold at 10 kHz is only =43.0 dB. If the young adult can just barely hear a 10 kHz tone, by what factor must the intensity of the sound wave be amplified so that it is heard by the older person?

The sound level measured in a room by a person watching a movie on a home theater system varies from 45 dB during a quiet part to 65 dB during a loud part. Approximately how many times louder is the latter sound?