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Homework Help: Constructive/Destructive Stereo Interference

  1. Dec 4, 2007 #1
    1. The problem statement, all variables and given/known data
    You are sitting in your room listening to music on your stereo. The music you are listening to is verystrange, consisting only a steady pure tone with a frequency of 740 Hz. The music is playedthrough two speakers, which are perfectly synchronized. You are sitting exactly 1.22 m away from one speaker, and 2.38 m away from the other. The temperature in the room is 22oC. Find the difference in the distance traveled by the sound waves from each speaker as they move to you and determine whether you are sitting at a point of destructive interference (a dead spot) or a point of constructive

    2. Relevant equations
    constructive interference pattern: d1-d2 = n[tex]\lambda[/tex]
    destructive interference pattern: d1-d2 = (n + 0.5)[tex]\lambda[/tex]

    3. The attempt at a solution
    I'm not even sure where to start. I understand the patterns and they make sense, but I'm not sure what to do with the information I've been given. I found the speed to be 344.08m/s but I'm not sure when that would come into play. Any advice?
  2. jcsd
  3. Dec 4, 2007 #2
    You need to use the speed to find the wavelength. ( v = lambda x f )

    Then you can use your equations to determine whether you are in a dead spot or not.

    d1 = distance from one speaker
    d2 = distance from other speaker

    n = 0, 1, 2, 3, 4, 5 etc.......
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