To calculate the combined intensity level when two sounds are present, you need to use the concept of sound intensity in decibels (dB), which follows a logarithmic scale. When two sounds are combined, their intensities add up logarithmically rather than linearly.
To determine the combined intensity level, you can use the following formula:
L_comb = 10 * log10(10^(L1/10) + 10^(L2/10))
where L_comb is the combined intensity level, L1 is the intensity level of the first sound, and L2 is the intensity level of the second sound.
Let's calculate the combined intensity level for a first sound with an intensity level of 75 dB and a second sound with an intensity level of 72 dB:
L1 = 75 dB L2 = 72 dB
L_comb = 10 * log10(10^(75/10) + 10^(72/10))
Calculating the values within the parentheses:
L_comb = 10 * log10(10^7.5 + 10^7.2)
Using a calculator:
L_comb ≈ 10 * log10(31622.78 + 15848.93)
L_comb ≈ 10 * log10(47471.71)
L_comb ≈ 10 * 4.676
L_comb ≈ 46.76 dB
Therefore, when the two sounds with intensity levels of 75 dB and 72 dB are combined, the resulting combined intensity level is approximately 46.76 dB.