Plots and graphs and stuff

Discussion in 'Speakers & Subwoofers' started by Shane Morales, Nov 13, 2003.

  1. Shane Morales

    Shane Morales Second Unit

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    [​IMG] How the hell do you make the frequency response plots/graphs for your speakers? Any past threads discussing this?

    I have a feeling that if I make one of these for my system it will be really bad.
     
  2. Shane Morales

    Shane Morales Second Unit

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    I think I figured some of it out.

    You use some kind of tone generator prog like WinISD to play some tones at regular hz intervals. Using an SPL meter you take measurements of the db reading for each tone. Then you plot it. Right?

    Do you do this one speaker at a time or with all of them running? I know you do the sub by itself. What about everything else?

    Then what? You can use something like a BFD on your sub, but what about the other speakers. Once you have the graph, then what?
     
  3. ChrisWiggles

    ChrisWiggles Producer

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    Then you try to EQ your sub. I wouldn't EQ main speakers, IMO.
     
  4. Robert AG

    Robert AG Stunt Coordinator

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  5. Wayne A. Pflughaupt

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    Shane,

    You’re on the right track. The preferred method is to use a spectrum analysis software program like TrueRTA or ETF because it’s the easiest. You can do individual test tones and map your plot on graph paper, but as you can imagine this can be a pretty daunting task if you’re talking about doing all the speakers. As far is the intervals for readings, 1/6-octave is acceptable, but naturally 1/12-octave is better, if you’re feeling brave.

     
  6. Christ Reynolds

    Christ Reynolds Producer

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    could this be done with excel and a rat shack spl meter? i plan on doing this for a little demo project for one of my electronics classes. honestly, appearance takes precedence over accuracy. i wont be calibrating these speakers, they actually arent good speakers, in comparison to my amp. however, i'd like to be able to make nice looking graphs for this project. anybody have any tips? or is it just as easy as plugging numbers into excel and plotting the db readings as a function of frequency? it may be a lot of work using excel, but i am limited to the tools i have access to. thanks for any help.

    CJ
     
  7. PaulDF

    PaulDF Second Unit

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  8. Edward J M

    Edward J M Cinematographer

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    Wayne kicks ass - great forum resource. That is all; carry on. [​IMG]
     
  9. Brian L

    Brian L Cinematographer

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