# Homework Help: Acoustics: Amplitude/frequency/area in regards to sound power

1. Mar 31, 2009

### cb88bear

I really don't understand this problem at all...my thoughts were that for:
a) you triple the area, sound power would be greater
b) you double the frequency, the period it takes for the sound power to generate is cut in half
c) if you triple the amplitude, the output would be louder
d) you need a large sized loudspeaker to handle the amount of power generated
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For radiation from a sound board of area AREA, vibrating with amplitude A at frequency f we find power for P radiated:

P=(2.8x10^5 newton/m^2)((AREA)A^2f^2)/(c))

**Sorry about that formula...i don't know how else to write it on here***
a)If the amplitude and frequency are kept the same, but the frequency of the sound board is tripled, what happens to the sound power radiated?

b) If the amplitude and area are kept the same, but the frequency of the sound board is doubled, what happens to the sound power radiated?

c) If you triple the amplitude of the vibration of the sound board (changing nothing else), how does the sound power output change?

d)How does this formula explain the large size of "woofer" loudspeakers?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution