Question

Using a frequency-measuring lab device, I am to map out the sound intensity level distribution (dB) in a room (both with & without music playing) to create a 5x5 grid of 25 data points.
Using the following data table of sound intensity level β(dB) and corresponding intensity I(W/m2), I also need to find the intensity to the nearest order of magnitude for the points on my sound intensity level maps.

Here is the data table:
Intensity levelβ(dB) Intensity I(W/m2)   Example/effect
0 1×10–12   Threshold of hearing at 1000 Hz
10   1×10–11   Rustle of leaves
20   1×10–10   Whisper at 1 m distance
30   1×10–9   Quiet home
40   1×10–8       Average home
50   1×10–7   Average office, soft music
60   1×10–6   Normal conversation
70   1×10–5   Noisy office, busy traffic
80   1×10–4   Loud radio, classroom lecture

My question is how do I determine the sound intensity level (in dB) and intensity (W/m2)? To do these calculations, I need to take into account the frequencies that I measure throughout the room as well as the dimensions of the room, correct? I am not sure which equations to use to get from frequency to dB. Thanks in advance for any help in understanding this material!

Answer 1

Intensity level order of Intensity I in W/m² ß in dB magnitude -12 10 - 12 -1/ 10 10 -10 20 1010 0-9 30 10 -9 - 8 40 1098 50 10 6 60 - 6 10 -5 70 10-5 80 10 4 -4 wave Intensity of sound can be found using the equation, I-25288 A² v where, & density of medium 8 frequency of An amplitude the ware V speed of the ware Intensity of sound can also be found using the relation, of P Power output = 12 Ia A area Intensity level 8 of a sound is 8 = 10 log ( 1 ) in dB where, I intensity of given sound wave in wint Io standard intensity & 10 2 1x1072 W/m2