If the intensity level of one trombone is 70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all playing simultaneously in the same place?
A) 70 dB
B) 146 dB
C) 89 dB
D) 82 dB
E) 76 dB

Question

If the intensity level of one trombone is  70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all playing simultaneously in the same place?
A)  70 dB
B)  146 dB
C)  89 dB
D)  82 dB
E)  76 dB

Quizplus · Accepted Answer

The intensity level in decibels (dB) increases logarithmically as the number of sources (in this case, trombones) increases. Doubling the number of sound sources increases the intensity level by about 3 dB. Since 76 is roughly 2^6 (or 64) times one trombone, the increase in intensity level would be 6 times 3 dB = 18 dB. Adding this to the original 70 dB gives us 88 dB, which rounds to the nearest offered answer, 89 dB.

If the Intensity Level of One Trombone Is 70