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Sound problem

  1. Jun 15, 2008 #1
    I have a question about sound transmission through air. In blocking the sound with a structure is it better to put the structure next to the sound source or next to me?
    I'd like to put up a shed to block the sound of my neighbor's hot tub. When it's running I can hear it in my house. Would the shed be more effective if it were closer to the hot tub or closer to my house? The hot tub is 20 ft from from the property line and my house is 15 ft from the property line. My wife thinks the shed should go near the house and I think it would work better closer to the source of sound. Where is best. Thanks
     
  2. jcsd
  3. Jun 15, 2008 #2
    Hey.
    Next to you, because as sound travels a distance it gets quieter because it will be absorbed by other objects in its path. By having it away from the source, you will have already diminished sound trying to get through your shed.
     
  4. Jun 15, 2008 #3
    Thanks for the quick response Ed. However, I don't think I agree with your answer. Sound does not diminish because it gets absorbed by objects in its path. Objects reflect sound. Sound is diminished at the rate dictated by the inverse square law. A point source radiating into a solid angle. That shed should reflect and absorb the sound and only leave a diffused source. I'm sorry to disagree with you but don't you think this is rather a good exercise? Anybody want to chime in on this, I would be very glad to hear from you. Thanks Ed.
     
  5. Jun 16, 2008 #4

    FredGarvin

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    Your neighbor's hot tub must be a pretty cheap model. I have mine right next to the sliding glass door in our den. When that kicks on I can't hear a thing.

    From an industrial standpoint, it is always better to attenuate a signal at the source since there are so many factors that can affect the sound in the far field. This isn't necessarily the case here, but I think I agree with you in that the shed should be closer to the source. However, understand that you will still get reflections and probably some diffraction from the source. My opinion would be to put up a hedge or trees in between. It would be much more effective than adding another solid surface to bounce sound off of. Or, if that's not feasible, is your neighbor a nice enough person that you could look at adding insulation and maybe some panels to his tube frame?
     
  6. Jun 16, 2008 #5
    Fred,
    Thank you for you rresponse. I'm starting to think that some pecentage of the problem is resonance in that area of my house. You triggered that line of thought when you mentioned the patio doors in your den. Glass has a very high resonant frequency, not to mention it's ability to reflect sound. My neighbors are just noisy people and they don't seem to be aware of that fact. I find this to be an interesting problem to solve and I'm sure it will require a combination of things. I even considere active noise cancellation because of the predictable wave form of the hot tube. Any more ideas very welcome. Thanks again Fred.
     
  7. Jun 16, 2008 #6

    FredGarvin

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    No problem.

    In your case, I wouldn't necessarily say resonance as the main problem. I would say echoing or reflection are your big problems to contend with. I am not an acoustician, but I would think that most residential sound sources would not have enough energy to really induce a structure's resonant modes to an audible level.

    A noisy neighbor is a tough nut to crack. I have the same issue with a family behind us. They simply don't realize that they are very loud. I have hinted to them but I admit I haven't come right out to ask them to quiet down which would probably solve 99% of the problem. It is an interesting problem. The active noise cancellation would be kinda cool if you could get it to work.
     
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