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Two loudspeakers, finding amplitude.

  1. Nov 27, 2007 #1
    1. The problem statement, all variables and given/known data
    Two in-phase loudspeakers emit identical 1000 Hz sound waves along the x-axis. What distance should one speaker be placed behind the other for the sound to have an amplitude 1.60 times that of each speaker alone?

    2. Relevant equations
    None given, but I assume:
    A = 2asin(kx)

    3. The attempt at a solution

    1.6a = 2asin(kx)

    Found k=(2pi)/wavelength = (2pi/0.343)
    using v = 343 m/s


    x = 0.0506m

    But this answer is wrong. Help?
    Last edited: Nov 27, 2007
  2. jcsd
  3. Nov 27, 2007 #2


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    Homework Helper

    You have to add the amplitudes as vectors.
    (1.6*a)^2 = a^2 + a^2 + 2*a*a*cos(phi) where phi is the phase difference = 2*pi*x/wavelength
  4. Nov 27, 2007 #3
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