Intensity of a Loudspeaker, What's wrong with calculation?

AI Thread Summary
The discussion revolves around calculating the intensity, displacement amplitude, and pressure amplitude of a loudspeaker system emitting sound isotropically at a frequency of 1770 Hz. The intensity at a distance of 30.8 m is sought, along with the displacement and pressure amplitudes at 5.66 m. The user attempts to apply the equation for displacement amplitude but arrives at an incorrect result, leading to confusion about the calculations. They also express uncertainty regarding the relationship between amplitude and pressure, indicating a lack of understanding of the underlying concepts. The thread highlights the challenges faced in applying theoretical equations to practical problems in acoustics.
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Homework Statement


A certain loudspeaker system emits sound isotropically with a frequency of 1770 Hz and an intensity of 0.892 mW/m2 at a distance of 5.66 m. Assume that there are no reflections. (a) What is the intensity (in mW/m2) at 30.8 m? At 5.66 m, what are (b) the displacement amplitude and (c) the pressure amplitude of the sound? Take the speed of sound to be 343 m/s and the density of air to be 1.21 kg/m3.

I mostly need help with part b, I believe I can get part c with the answer from part b.

Homework Equations



I = 1/2(ρvω2sm2)

The Attempt at a Solution



So, for part b and from the relevant equation:

sm = (2I/ρvω2)1/2

ω = 2πf = 2*3.14159*1770 = 11121.24 Hz

So, using the above equation and plugging in I = 0.892 mW/m2, ρ = 1.21 kg/m2, and v = 343 m/s, I get the answer 5.895 x 10-6 m. However, this answer is apparently wrong, and I'm not sure why. Is there something wrong with my calculations?
 
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intensity is the power/area covered. Such areas are usually spherical. so at a distance of 5.66meters,

.892E6W=
8.92E5W/m^2=power(dE/dt)/4pie(5.66)^2 if this really is a sphere and get power using algebra.

once you get power, intesity=power/4pie(30.8)^2 I don't get neither b or c. lol I didnt study pressure yet. I don't even know what amplitude affects.
 
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