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New VTF-15H measurements - Using the DIY WM-61A Mic

Discussion in 'Subwoofers' started by nelmr, Dec 28, 2010.

  1. nelmr

    nelmr Active Member

    This should be much more accurate than the RS meter measurements found at this post (you can click to compare if you'd like):

    http://www.theaudioannex.com/forum/viewtopic.php?f=17&t=1063

    Anyway, here is the FR response from 10-100 (I up'ed it from 80). The main Right Front speaker is on but crossed over at 200hz. I'm going to make two more batches of measurements from the center couch cushion (sweet spot of the room). I'm gong to move it a few inches to the left and right and up and down to average for an even more accurate response. I'll post the averaged results later in this thread. In the meantime feel free to interpret the various settings on the VTF-15H

    [​IMG]
    [​IMG]
     
  2. nelmr

    nelmr Active Member

    Okay I took the 45 measurements needed 1 in the sweet spot. one a little infront and to the left, and the other a little behind and to the right. All measurements though where still inside the center seat cushion area. I apologize for not keeping the colors the same as the previous graphs, but that would have been too much work.

    [​IMG]
    [​IMG]

    NOTE: The irregularity at around 84Hz on one of the plots was an artifact of ambient noise, not measured response, so ignore that.
     
  3. PaulyT

    PaulyT Behind the Curtain Staff Member Administrator Moderator Superstar

    Ok, I see a lot of work going into a lot of graphs. Good show! But, playing a bit of devil's advocate here - no disrespect intended because playing with measurements like this is fun in itself - what's the take-home message? The port/Q changes seem to only affect the region from ~50Hz down. Just how audible are any of these differences? Sure there's a 20dB spread at 20Hz, but the human hear can barely comprehend frequencies that low, it becomes more of a shaking than a note. How does one determine which of these many combinations of settings is "best"?
     
  4. nelmr

    nelmr Active Member

    To make it a little easier to see the deep base differences, I've adjusted the plots to have the same SPL between 60-70hz:

    [​IMG]
     
  5. nelmr

    nelmr Active Member

    Re: New VTF-15H measurementhttp://wws - Using the DIY WM-61A

    Devil's advocate is fine. I agree with you thoughts mostly here. This sub sounds great at most any setting, though I'd really have to spend a lot of time comparing the settings with music and movies to see if I can hear a difference.

    It's just that the 15 combination plus phase adjustments leaves one to wonder what is best. Should one shoot for the flattest response (which seems to be the 1 port EQ1 or sealed EQ1 settings) or go for the most headroom (2 ports open EQ2). Here is the difference between the best "flat" response and the best headroom response (level adjusted):

    [​IMG]

    FYI: I'd like to point out that I should HSU my original RS graphs and these new ones won't really change anything. They say the sub in the EQ1 setting and 1 port plugged usually results in too much deep bass for most rooms. They said it doesn't appear I am getting much deep bass room gain in my room, so what is the flattest in my room obviously may not be the same in someone else's with these settings.
     
  6. soundhound

    soundhound Well-Known Member

    I would go for the setting which yields the flattest response down to 20Hz, unless you're listening at ear bleeding levels and hear the sub driver bottoming out on LF peaks.
     
  7. Flint

    Flint "Do you know who I am?" Superstar

    I second this advice.
     
  8. nelmr

    nelmr Active Member

    So if flattest to 20hz is ideal (without issues to the sub) which of these graphs is the overall flattest then? These are the flattest ported settings from what I can tell. The dark grey trace has my vote (1 port, EQ1, Q3). It's actually pretty flat down to 16hz.

    [​IMG]
     
  9. soundhound

    soundhound Well-Known Member

    The colors are a bit messed up, but the strongest one at 20Hz would be the one.
     
  10. yromj

    yromj Well-Known Member

    I would say 1 Port EQ1 Q7. That curve is the flattest, at least the way I see it.

    John
     

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