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Geometry

Discussion in 'Shooting Related Threads' started by recurvyarcher, Sep 26, 2010.

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  1. recurvyarcher

    recurvyarcher Well-Known Member

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    1. Mulitply the diameter by itself (square it).


    2. Multiply that answer by pi (you can use 3.14 for pi if you don't have a caclutor with the pi function).


    3. Divide the whole thing by 4. That gives you the answer for the area.


    I don't fully understand what you mean by how the circles relate to one another...are you talking acoustics?
     
  2. RickN

    RickN Well-Known Member

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    Radius squared X pi or 3.14 = area of a circle.

    The area of one 15" circle is more than 2 - 10" circles.
     
  3. RickN

    RickN Well-Known Member

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    For a 15" circle, the radius is 7.5"

    7½ x 7½ x 3.14 = 176.6

    10" circle would be 5 x 5 x 3.14 = 78.5
     
  4. recurvyarcher

    recurvyarcher Well-Known Member

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    Maybe you are just talking about how the acoustics change with circle size on the speakers, and not how the guitar's sound hole relates to the speaker size? If so, then the larger the diameter, the deeper the sound (and the smaller, the more treble).

    I can think of a human example that would help you to remember this principle.
     
  5. Bisi

    Bisi TS Member

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    I traded off my "Fender Bandmaster" tube amp years ago with 2 - 10 or 12" speakers for a state of the art solid state "Yamaha" amp with one - 15" speaker. WTH was I thinking?????? No comparision in sound quality, don't know if the multi speaker setup was the difference, or if one was a "Fender" and the other "Yamaha", or if one had tubes and the other was solid state, but there was a hugh difference.

    Stick with the 2 speaker setup.
     
  6. Jawhawker

    Jawhawker TS Member

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    shootlow, now you can go back to the guy and tell him that he is "geometrically imperfect".....
     
  7. Allen-MX8

    Allen-MX8 Member

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    Before I read RickN's reply I said to myself, "Radius squared times Pi" and wow, after 50+ years since I took Geometry in High School I remembered!

    Thanks RickN.

    Allen
     
  8. RickN

    RickN Well-Known Member

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    That's about the only thing I remember from Geometry class.

    Mr Skoonis would say "just remember pi r square."

    Me being the smartass...yup even back then, I'd say "Mom's pies are round."
     
  9. stokinpls

    stokinpls Well-Known Member

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    Pi R Squared?

    Heck no, "Pie are Round, Cornbread are square." Circa 1962, Mr. O'Neal.
     
  10. Trapmanjohn

    Trapmanjohn Member

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    Hey Bisi,

    In an musical instrument amplifier Tubes make all the difference. Always go with vacume tubes for a clear and warm sound. "State of the art" is not always the best. I am a bassist and after all this time the Ampeg SVT which was invented about 1968 is still the best sounding bass amp in my opinion. But who wants to carry it ! The SVT weighs about 100 pounds, and to replace all the tubes is about $700. Today, a good solid state amp has no tubes to replace (or maybe 1), and weighs about 6 to 25 pounds. However, with out a doubt, if I have to play a gig and get to request an amplifier that someone else has to lift and carry the Ampeg SVT is always first choice. You should have stayed with your Fender Tube amp. Tubes always win !

    Hit 'em hard,

    John
     
  11. timb99

    timb99 Well-Known Member

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    shootlow

    You can still hear??? After all these years of listening to hauxfan, I'm amazed!
     
  12. scooterbum

    scooterbum Active Member

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    Forget all of the convoluted high math formulas.

    The calc for the area of a circle is simple;

    Diameter squared times 0.7854.

    10 x 10 x 0.7854 = 78.54

    15 x 15 x 0.7854 = 176.7

    Simple, huh. (Engineer's secret!)
     
  13. whiz white

    whiz white Strong Supporter of Trapshooting Banned

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    As a mathematician myself, perhaps I can shed a dim light on your post.

    Area is a second degree variable, versus volume which is a third degree. As you increase the radius by a one linear unit, you are actucally squaring the change. Because you want to compare different sized circles, you can eliminate pi (a good approximation is: 355/113 or the more common, but less accuratre 22/7, because the comparison datio cancels out any units and constants). As you increase the radius, the function is increased by the square of the radius. Example: 10" diameter circle, radius of 5, gives a square of 25. Move to a 12" diamter, radius of 6, the square becomes , 36.

    What this means is this:<BR>
    5^2=25<BR>
    6^2=36<BR>
    7^2=49

    Therefore, a 10" circle compared to a 15" circle is in the ratio of: 25 units : 56.25 units or about 1 : 2.25.

    Now, I've really muddied up the waters, huh?

    WW
     
  14. phirel

    phirel TS Member

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    Whiz- Lets muddle it more. The actual area of a circle cannot be calculated, only estimated. The estimate is based on dividing the circle into triangles that begin in the center of the circle and the base of the triangles is treated as if it were a straight line but it is actually curved. The area of each triangle can be calculated. When the triangles get very small, the base becomes closer to a straight line and the area estimate is more accurate but it remains as an estimate.

    Pat Ireland
     
  15. phirel

    phirel TS Member

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    Bryan- You are correct and I should have known better. Thank you, I hope to never make that mistake again.

    Pat Ireland
     
  16. recurvyarcher

    recurvyarcher Well-Known Member

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    Five out of Four people have a difficult time understanding jokes about fractions.
     
  17. Pull & Mark

    Pull & Mark Well-Known Member

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    Thanks for the laugh Devi!!! Break-em all. Jeff
     
  18. ALF27

    ALF27 TS Member

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    If you want to make ANY bass amp sound REALLY good, add a Sonic Maximizer to the FX loop. I just bought one and ..... WOW!!!

    LA
     
  19. Squeal

    Squeal Member

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    Anybody have an idea of what a Fender Baseman 100 AMP is worth? I have one setting in my basement.
     
  20. Bisi

    Bisi TS Member

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    Squeal, watch ebay for a while, that would be my suggestion and see what they are bringing.

    I know it made me sick to see what "Fender Bandmaster" amps are selling for today. I gave mine alway. Another thing I screwed up. LOL
     
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