Question

What sound intensity levels must sounds of frequencies 60, 3000, and 8000 Hz have to have the same loudness as a 40-dB sound of frequency 1000 Hz (that is, to have a loudness of 40 phons)?

a) 40 dB
b) 43 dB
c) 46 dB
d) 49 dB

Answer 1

The sound intensity levels for frequencies of 60, 3000, and 8000 Hz to have the same loudness as a 40-dB sound of frequency 1000 Hz are approximately 46 dB, 43 dB, and 49 dB, respectively.

Step-by-step explanation:

To find the sound intensity levels that produce the same loudness as a 40-dB sound of frequency 1000 Hz, we need to refer to the equal-loudness curves.

According to Figure 17.38, sounds with frequencies of 60, 3000, and 8000 Hz would need to have sound intensity levels of approximately 46 dB, 43 dB, and 49 dB, respectively, in order to have a loudness of 40 phons (the same as the 40-dB sound). Therefore, the correct answer is (c) 46 dB, (b) 43 dB, and (d) 49 dB.