(a) What is the loudness in phons of a 100-Hz sound that has an intensity level of 80 dB?

(b) What is the intensity level in decibels of a 4000-Hz sound having a loudness of 70 phons? 

(c) At what intensity level will an 8000-Hz sound have the same loudness as a 200-Hz sound at 60 dB?

Strategy for (a)

The graph in Figure 17.34 should be referenced in order to solve this example. To find the loudness of a given sound, you must know its frequency and intensity level and locate that point on the square grid, then interpolate between loudness curves to get the loudness in phons.

Strategy for (b)

The graph in Figure 17.34 should be referenced in order to solve this example. To find the intensity level of a sound, you must have its frequency and loudness. Once that point is located, the intensity level can be determined from the vertical axis.

Strategy for (c)
The graph in Figure 17.34 should be referenced in order to solve this example.

Transcribed Image Text:

Sound level (dB) 120 100 80 60 40 20 0 -10 2120 phon 110 phon -100 phon 90 phon 80 phon 40 60 100 200 400 800 2000 5000 10,000 50 80 500 1000 4000 8000 Frequency (Hz) -70 phon -60 phon: 50 phon -40 phon -30 phon -20 phon -10 phon fo 0 phon Lyn