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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthordelprado
    • CommentTimeApr 11th 2018
     
    So I have the idea of basically making a stud wall in the garden, capped and infilled with something. Was after your advice on what wood is the cheapest but obviously also effortlessly air tight to at least stop direct transmission of sound (obviously things till go over the top). I assume it has to be WBP Ply?
    • CommentAuthorsam_cat
    • CommentTimeApr 11th 2018
     
    For what purpose/What problem are you trying to solve?
  1.  
    How thick do you want the wall? Making it airtight doesn't necessarily make it sound tight. Why can't you use high density concrete blocks. If timber use staggered studs and fill with sound absorbing egg crate foam?
    • CommentAuthorbarney
    • CommentTimeApr 11th 2018
     
    External fences, walls and the like create sound reduction by "bending" the sound path

    So basically, from a given source and knowing the receiver position, you can bend the path from a direct line by the use of a wall or fence - it's a combination of the deflection angle and the route distance that causes attenuation

    As a simple example, look at attenuation fences along side busy roads or motorways to adjoin residential properties.

    Basically a high fence, normally on steel posts, but often comprising hit and miss boarding on both sides - the sound(in this case a line source) has to climb over the fence and get back down to the receiver position. It can be easily calculated what the attenuation might be if you can draw out the basic geometry.

    Pay attention to the ends of the fence as sound will get around the ends as easily as it does over the top (with similar attenuation)

    If you could elaborate a bit more on the source and receiver positions, that might get a clearer response. Basically, you probably don't want to be worrying too much about mass or stiffness -the geometry is more important when you are dealing with external situations.

    If it helps, thing about the source if at ground level radiating energy into a hemisphere - from there you can easily work out that deflection is by far the dominant effect

    Regards

    Barney
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 12th 2018
     
    Barney
    Are there some basic tutorials somewhere, it may help.
    • CommentAuthorjfb
    • CommentTimeApr 12th 2018
     
    i've seen other fences by roads that were essentially rock wool sandwiched between wooden panels (horizontally woven branches in this instance). I did wonder how wet the rock wool ever got as presumably that would impact its noise reduction effect.
    • CommentAuthorbarney
    • CommentTimeApr 13th 2018
     
    Text books include

    "Woods Guide to Acoustics" - old school but a very useful publication

    "Acoustics and Noise Control" - Peters, Smith and Hollins

    Both the above are undergraduate level texts

    University of Sheffield - Acoustics Group have a lot of on line resources - try a google for "barrier attenuation equations"

    Regards

    Barney
    • CommentAuthorgoodevans
    • CommentTimeApr 14th 2018
     
    Now that takes me back to my final year project for my degree - I have no idea on the the title was but I developed a construction noise prediction program (on a Prime mini computer). Barney is correct - increase the noise path length and the 'angle' and ensure that you cope with the width. From memory to deal with the the noise from a line source (e.g. a road) it is (literally) equally important to shelter the receding/approaching road as it is at the near point.

    Noise is a tricky business - for road noise a complete barrier is much better than a tall barrier over part of the source - and I've seen some perspex barriers on the edge of roads which I'm sure must be affective - Give priority to height/width (within reason) then go for mass/adsorption.
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 14th 2018
     
    Posted By: barneybarrier attenuation equations

    Stuff like this.
    https://www.engineeringtoolbox.com/outdoor-sound-partial-barriers-d_65.html
    • CommentAuthorbarney
    • CommentTimeApr 16th 2018
     
    Yes, that sort of thing ST

    There are slightly differing metrics - but the basic equations remain the same

    Regards

    Barney
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