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Do I need equalization with this frequency response?

Discussion in 'Speakers' started by GregBe, Sep 30, 2005.

  1. GregBe

    GregBe Well-Known Member

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    I am not sure how to add my graph here, so I will post my numbers that are the compensated spl's. If someone can tell me how to post the graph, I would be happy to do so.


    20hz = 68.2spl
    22.5hz= 69.4spl
    25 = 74.4
    27.5 = 74.7
    30 = 76.4
    35 = 71.5
    40 = 72
    45 = 72.7
    50 = 69.3
    55 = 63
    60 = 64.9
    65 = 74.8
    70 = 73.7
    75 = 71.5
    80 = 71
    90 = 70.4
    100 = 70.3
    110 = 62.25
    125 = 56.2
    140 = 62.5
    160 = 60
    200 = 62

    When you look at the graph, it looks great form 110 down through 65. It also looks real good from 50 down through 25. I don't see any real peaks. It looks like there is a dip from 50 to 65. Is this something to worry about?

    Thanks
    Greg
     
  2. Brian Fellmeth

    Brian Fellmeth Well-Known Member

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    Your way better off than most. I would be satisfied with that for movies. Bassy music would benefit slightly by flatening that out.

    I assume these are pure sine waves ? Warbles will make the curve look better than it is.
     
  3. gene c

    gene c Well-Known Member

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    What did you use to come up with these numbers? I'd love to plot my own.
     
  4. FeisalK

    FeisalK Well-Known Member

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    Greg, check out http://www.photobucket.com/ to host your pictures, and you can use the [ I M G ] tag for referencing here

    Gene, you can do you own with a SPL meter (radioshack, about $40) and some test tones burnt onto a CD.

    There's a guide on how to do this on Sonnie Parker's excellent BFD guide about a quarter way down the page (MEASURING SUB SPL LEVELS & USING MICROSOFT EXCEL WORKBOOK). You can download test tones and the excel workbook from there.

    Once you have a graph, you might find some peaks (boomy) and dips (loss of sound) in your frequency response, and if there are, you'll WANT to fix it. [​IMG]
     
  5. gene c

    gene c Well-Known Member

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    Thanks Feisal. My list of things to do on a rainy day just keeps on getting longer and longer!
     
  6. FeisalK

    FeisalK Well-Known Member

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    haha, mine too but i won't wish a rainy day on anyone [​IMG]
     
  7. GregBe

    GregBe Well-Known Member

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    Yes those are pure sine waves I downloaded from the ACI site. I have a one band equalizer on my sub that I can increase the spl at 20 and 22.5 hz to get it really flat from 35 down to 20. The only problem is I lose about 3dB of headroom. I am now trying to figure out if the additional response down low is worth that loss.
     
  8. Sonnie Parker

    Sonnie Parker Well-Known Member

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    If you guys need your graph hosted, let me know. I'll host it on the BFD Guide and you can use that URL for your image link anywhere you like. I'm lookin' for graphs to place on the page anyway.

    Just shoot me an e-mail.
     
  9. John Garcia

    John Garcia Well-Known Member

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    Hey Greg, that's about as good as one could hope for without equalization. Lucky guy...[​IMG]
     
  10. Sonnie Parker

    Sonnie Parker Well-Known Member

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    I don't know John... these don't appear to be even octave measurements. I rather see some 1/6 octave measurements.

    Greg, what program are you using? I'd recommend downloading the MS Excel Workbook from the BFD Guide page and taking some 1/6 octave measurements, plugging them into the workbook and let's look at that graph.

    I see the weak spot at 55-60hz and if it's not a room null then it could be worked out. Another thing is for movies you might want to roll off a little from 65hz out to about 100hz. IOW... work on a house curve to give you a better low end on movie watching. You can get this preset to flat for music if you want and then copy it over to the next preset and work on a house curve for movies.
     

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