Quick BFD question

Discussion in 'Archived Threads 2001-2004' started by Richard Burzynski, Feb 19, 2002.

  1. Richard Burzynski

    Richard Burzynski Second Unit

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    BFD Users:

    How many bands of EQ correction are you guys using on your sub signal. I realize answers will vary, I'm looking for an average # of bands.

    Thanks.

    Rich B.
     
  2. Kevin C Brown

    Kevin C Brown Producer

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    Rich- I am using 5 bands, but I am getting the most bang for the buck out of the 1st 3.
     
  3. Rick Radford

    Rick Radford Supporting Actor

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    6 filters. But since each room/sub combo must have a unique response, I'm not sure what this info really does for you.
     
  4. Richard Burzynski

    Richard Burzynski Second Unit

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    Thanks for the replies.

    I found a nice (& affordable) 5 band parametric EQ w/ subsonic filter (a feature I would like), but it only has 5 bands. No sure if 5 bands will be enough. I know that actually measuring my sub/room response would answer this question, but system is not completely set up yet.

    Rich B.
     
  5. Rick Radford

    Rick Radford Supporting Actor

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    >but it only has 5 bands<

    Oh, I see. Frankly, unless you have an unusual situation, I'd think 5 bands will work just fine.. especially since it's a parametric eq.

    OOC, what does a subsonic filter do and why would I want/need one?
     
  6. Kevin C Brown

    Kevin C Brown Producer

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    Rich- Sounds like you're looking at either Rane or Symetrix? [​IMG]
     
  7. Richard Burzynski

    Richard Burzynski Second Unit

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    Actually our nice friends over at Behringer, (the BFD folks) have a nice mono EQ, model peq2200 http://www.bswonline.com/public/prod...p?item=PEQ2200 and its online price is only $99.
    Subsonic filter removes unwanted lower frequencies that your non-SVS sub may not be able to handle. [​IMG]
    Rich B.
     
  8. Leon O

    Leon O Stunt Coordinator

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    Hi Rich,

    I took a very quick look (busy at work) at the specs. It looks like the bands are not full sound spectrum. Only 2 of the bands had ranges starting below 150hz. I hope someone can say differently, because I'd love a parametric EQ at that price.

    Leon
     
  9. brucek

    brucek Second Unit

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    Rick,

    Commercial sub amplifiers will have a subsonic filter to reduce the level of very low frequency information to remove signals that would bottom the driver if allowed to pass.

    This is a concern for those who make DIY subs and then use a power amp without a subsonic filter and they hear that terrible clank clank of their driver extending too far.

    Some equalizers have a switchable subsonic filter that is useful if your sub doesn't have one. A BFD does not have a subsonic filter.

    brucek
     
  10. Rick Radford

    Rick Radford Supporting Actor

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    Thanks for the explanation, guys.

    Within this line, where (if any) does a subsonic filter exist?

    Onkyo 989 -> BFD1124p -> Samson 700 -> SVS 20-39cs

    I have heard my sub hit bottom once! There was no question as to what it was. At the time, I was setting the level of my Bass Peak level limiter of the 989.

    Since then if I make an adjustment to the BPLL, I've taken Guy Kuo's suggestion to move up very close to the sub so I can hear the very first signs of the sub bottoming out, then back off a dB or two.

    If a BPLL is utilized, is a subsonic filter of any use?
     
  11. brucek

    brucek Second Unit

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    Rick,
    My understanding is that the Samson has a subsonic filter built in it. This is one reason that SVS recommends and sells it.
    If you're bottoming your SVS out even with BPLL then maybe you need two or three... [​IMG]
    brucek
     
  12. Rick Radford

    Rick Radford Supporting Actor

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    >the Samson has a subsonic filter built in it<

    I didn't know that. That's good to know.
     
  13. BruceD

    BruceD Screenwriter

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    The cost difference between the $99 EQ and a BFD 1124P for $129 is pretty small, while the capability differences are huge in favor of the 1124.

    I'd go for the 1124
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    Most subs themselves, do not include a subsonic filter, right?
     
  15. brucek

    brucek Second Unit

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    Kevin,

    It's my understanding that all commercial subs, plate amps and so-called sub amplifiers (Mackie, Samson) have some sort of subsonic filter to remove very low frequencies down to DC. I suspect the roll off must begin around 10Hz or so.

    Ported type speakers will unload below their tuned resonance frequency and the cone can bottom causing a metal sounding clunk if fed subsonic information because of a loss of resistance to driver cone movement. A subsonic filter will help alleviate this problem.

    brucek
     

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