My FR graph with the PB12-Ultra/2, advice??

Discussion in 'Speakers' started by Scott Goldsmith, Oct 28, 2004.

  1. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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    Here's the numbers and the plot....

    [​IMG]

    [​IMG]

    What do you all think??? These are without using the PEQ on my Ultra, so I can manage the curve (with the help of Robb of course [​IMG])

    Thanks in advance!
     
  2. Eric A

    Eric A Second Unit

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    Scott,
    This curve looks great. You basically have a "house curve" once you remove the hump centered around 40hz. Smooth tha out a bit and you should be golden. I would not worry about the 100hz bump unless you are crossing over above 80hz.
     
  3. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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    Eric - Thanks dude! I'm crossing over at 80hz, so I will ignore the above 80hz part [​IMG] I would like to get a Rane to fine tune things, but since I have to use the PEQ on the Ultra's amp, I will have to consentrate on one spot, maybe the 40-42hz area. I got a suggestion to boost the 56-80hz area to bring it up, but not sure what that will do to the amp, overpower, etc.

    Decisions, decisions [​IMG]
     
  4. ScottCarr

    ScottCarr Second Unit

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    Not that bad scott. I would play with th e PEQ a little and see wha happens. You migh like the extra dbs in theat range
     
  5. Robb Roy

    Robb Roy Supporting Actor

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    Scott,

    The PEQ on the PB12-Ultra/2 is for cut only -- it's unable to provide boost. When I come over we'll run several sweeps and see what we get after going through the continuously variable phase (your graph might look different) and then we'll tame the biggest peak with the PEQ on the sub.

    -Robb
     
  6. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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    Cool, I figured it couldn't boost, just checking. I would like a relatively flat curve, your Ultra sounded great really flat, and plus I run my sub 5db's hot so I don't need those peaks to be even larger peaks [​IMG] I appreciate everything Robb!!
     
  7. Kevin C Brown

    Kevin C Brown Producer

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    Yes, that curve doesn't look bad at all. Scott- How exactly did you generate it?
     
  8. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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    I have a test tone CD, with the test tones in that exact octave breakdown, 1/6 octave from 16 to 160. I set the receiver to a moderate level, -22 on mine for this test, then play the track on the player, measure what the Radio Shack SPL meter says, write it down, then put the values in the subtestmodel excel sheet that I downloaded. It will automatically adjust for the correction factor needed when you use the Radio Shack SPL meter, then it makes a graph for you to see, all what I posted [​IMG]
     
  9. Edward J M

    Edward J M Cinematographer

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    Use the PEQ to nail the 40 Hz hump and you're golden. Piece of cake.

    Ed
     
  10. Kevin C Brown

    Kevin C Brown Producer

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    Scott- Do you have a link to the "subtestmodel excel sheet"? Looks like it's doing some smoothing too?
     
  11. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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  12. Kevin C Brown

    Kevin C Brown Producer

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    Yes, I've seen other people use this same spreadsheet. Just that when I do it with a "regular" spreadsheet, it never looks as good as this one. So I wanted to try this way. Thanks. If I can get mine done while this thread is still active, I'll post mine too.
     
  13. Scott Goldsmith

    Scott Goldsmith Stunt Coordinator

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    No problem, hurry and get it done! [​IMG]
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    OK, let's see if this works...

    [​IMG]

    Some notes: 60 Hz crossover (so I look good there), and the volume below 60 Hz is matched with above (I still think this is the best way of setting sub volume!). "7.1" is basically the test tones being sent to all channels. I am using the Stryke Basszone Test CD, and it's freqs are slightly different than the snapbug spreadsheet so I just adjusted. 12.5 Hz, baby. My last sub, a Vandersteen V2W which I just adored, was flat to 21 Hz, and -6 dB at 20 Hz. So now you can see why I finally got an SVS. [​IMG] As far as eq'ing, I suppose I could go after that peak at 63 Hz. It *is* using the "smooth function" in Excel. Neat! Scott, I think yours does look slightly better than mine. [​IMG] Thank you for getting me motivated to do it this way.
     
  15. KeithY

    KeithY Stunt Coordinator

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    Are you guys just plugging in your numbers, editing that speadsheet? Whenever I've made a graph it looks nothing like this.

    [​IMG]
     
  16. KeithY

    KeithY Stunt Coordinator

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    Are you guys just plugging in your numbers, editing that speadsheet? Whenever I've made a graph it looks nothing like that.

    [​IMG]
     
  17. Kevin C Brown

    Kevin C Brown Producer

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    Looks like you need to make the Hz row the X-axis at least. Other than that, looks OK.

    I just used the snapbug spreadsheet as-is. (But I added the lower freqs, and I adjusted the calib numbers some.)

    Oh yeah, I'm using the 16 Hz tune.
     
  18. Wes Nance

    Wes Nance Stunt Coordinator

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    Kevin,

    I'm using the Stryke CD to generate tones as well, and don't have the Excel chops to change it around. Could I get you to post a link to your edited Excel sheet or email it to me? I'd like to see the response down to 12.5 hz, etc.

    Thanks!

    Wes Nance
     
  19. Edward J M

    Edward J M Cinematographer

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    Wes, drop me a line or swing by; I'll give you the Excel spreadsheet I used for the PB12-Plus/2 review. It has 1/12 octave intervals and goes down to 10 Hz and has c-weighted correction factors built in. It has separate spreadsheets for each state of tune (even mismatched tunes), and then graphs all of them together for a comparative look.

    Regards,

    Ed
     
  20. Michael Varacin

    Michael Varacin Stunt Coordinator

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    2 questions: The Radio Shack SPL meter claims it's only good for frequencys down to around 35 Hz. Has it been confirmed how it measures responses below that?

    What correction factor are you talking about that is needed for the Radio Shack readings?


    I installed my PB12-2+ a few weeks ago, and I thought it made me very dizzy. I finally did a frequency scan, and I get a huge 15+ db peak around 35-25 hz. But I'm not sure if I am supposed to trust the meter there or not. That is before and correction factors.
     

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