So who uses an EQ for their sub?

Discussion in 'Speakers & Subwoofers' started by Michael Varacin, Nov 2, 2004.

  1. Michael Varacin

    Michael Varacin Stunt Coordinator

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    I'm curious...how popular is using an EQ to flatten bass response?


    I have a huge 20db peak between 25-35Hz, and I am trying to decide of an EQ is worth it. I can't move the sub to a different location.

    So how many people have purchased EQ's?
     
  2. Rob Kramer

    Rob Kramer Second Unit

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    Ive swapped resistors im my sub's amp in order to cutout a 6dB peak with great results.

    20 dB is one hell of a peak though.
     
  3. Brian L

    Brian L Cinematographer

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    IMHO, its the ONLY way to straighten out in-room bass response.

    I have used a AudioControl Bijou, and currently use a Behringer Feedback Destroyer.

    FWIW, there is an interesting series of article in the current Absolute Sound relating to room correction (for the most part TAS is rubbish, but I read it for entertainment purposes).

    Short story: EQ for the bass is essential to getting things right in your room. They are pretty late to the party, but I could not agree more. Shame they focus on multi thousand dollar devices, rather than stuff like the BFD, which I would wager can give any of the high $$$$ devices a run for their money if used properly.

    BGL.
     
  4. Eric Ha

    Eric Ha Stunt Coordinator

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    It is the only way to go IMO. I use a Rane PE-17 eq and love it. I had a 25db null at 40hz, as well as various other peaks and dips. I'm now within 8db from 16hz to 80hz.
     
  5. Ryan Tsang

    Ryan Tsang Second Unit

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    Count me in. I use a Behringer FD. I would not assemble a half decent HT without one. I think I paid $225cdn.
     
  6. Wayne A. Pflughaupt

    Moderator

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    I’d say everybody and his dog. [​IMG] Do a search on this forum and our DIY and Advanced Projects Forum for “Behringer Feedback Destroyer” and “BFD.” You’ll probably get hundreds of hits.

    Regards,
    Wayne A. Pflughaupt
     
  7. Joe Mihok

    Joe Mihok Second Unit

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    *raises hand*

    I'm using a BFD with a 194L Tempest DIY Sub.I've tried various "house curves" and found that a flat response sounded better. Right now I'm +/- 2db from 18-80hz. It sounds simply fantastic and I would never even think of owning a sub without my trusty BFD. I paid $185 CND. Best money on HT I've ever spent.
     
  8. Greg_R

    Greg_R Screenwriter

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    I used to employ an EQ until I leveled the response via other means (acoustic treatment and placement).
     
  9. Ryan Tsang

    Ryan Tsang Second Unit

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    True story: just got a Servo-15 v1. running 5ch small, X-over 80hz on prepro. Using the snapbug program and the sine wave test tones I graphed 5 potential setups. The best one gave me a peak to null max difference of 22db between 90-20hz! After some time spent on the BFD, I was able to get it +2/-3db between the same range.

    Before I EQ'd the Servo, it sounded worse than my previous setup (which was EQ'd). There was so much material coming from the sub even after level matching that it was ridiculously localizable. I thought it was the upper bass and for a while I regreted not buying the X-30 external X-over. After the diagnosis and re-config the bass mgnt in my prepro, I found the problem: a huge plateau from 45-25hz, not 80-110hz where I had thought. Anyways...if it wasn't for my BFD, I'd be lost.
     
  10. Martin Rendall

    Martin Rendall Screenwriter

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    I too had a huge 20+db peak centered around 25Hz. Basically it meant that if I calibrated the sub to the mains using Avia, some frequencies were effectively lost, while others were too noticeable. It sounded like a 1 note sub. I also had a wide dip around 54Hz. And there was no way I was able to integrate with my mains between 100Hz and 160Hz. Response was a sine wave with a 20dB amplitude.

    A BFD sorted all that out. Things sound more balanced now. I'm honestly not sure whether EQing the upper bass region is the right thing to do, but certainly getting rid of the huge hump at 25Hz and boosting a bit at 54Hz made a world of difference.

    Martin.
     
  11. Eric C D

    Eric C D Second Unit

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    Another huge vote for. For me, there have been two moments of bass enlightenment. The first was when I got enough subwoofer to vibrate the walls (and me). The second was when I flattened the response with eq and was able both to hear the different frequencies (Hey, bass can be musical!) as well as hear the bottom end of my sub rather than just the hip-hop-like thump at around 35-45 hz (my room mode).

    For me, adding an eq was an equal step up to adding the subwoofer.

    enjoy,

    P.S. Rane PE-17.
     
  12. Max F

    Max F Second Unit

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    I've got a BFD heading my way by mail...

    I started a whole thread about how my cheap (but good) Dayton 10" sub sounded fat to me for music (works great for HT). Many people said it was my room and not my sub. I think they're right. I've got peaks centered around 40 hz, 60 hz, and 90 hz. I guess i'll find out after equalizing if this sub can be "musical". If not, time for an upgrade - probably build a sealed 15" Tempest sub.

    Stay tuned!
     
  13. Ryan Tsang

    Ryan Tsang Second Unit

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    okay... since now I'm among EQ "experts" I'm gonna throw out a question that I've been stuggling with.

    when you guys Eq your subs with a test cd, do you do it with the sub by itself and the L and R disconnected?

    My dilemma is that although I cross off my towers at 80hz, there is still reasonable output at 50hz or so. My prepro has 2nd order x-overs (is that 12ob/octave?). So, if my sub by itself is flat, then if played together wouldn't I get
    more bass from 50-80hz?

    By that logic, shouldn't I EQ my sub to begin falling off above 50hz, so that when added with the mains, the combined FR is flat?
     
  14. Wayne A. Pflughaupt

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    Do your tests and EQing first with the sub only, then add the mains. When the mains are added you may see some changes an octave or so above and below the crossover point. Most of those, especially below the crossover point, you can probably address with additional equalization.

    Regards,
    Wayne A. Pflughaupt
     
  15. Kevin C Brown

    Kevin C Brown Producer

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    I also use an eq. But I don't have it hooked up at the moment. (I'm on a "simpler is better" kick right now.)

    At times in the past, I've had up to 5 filters activated in my BFD, but most of the time I just go after the largest peak. I have it out of the loop right now, because the last calibration I did actually didn't show any peaks worth flattening. (Manual method with test tones vs with www.etfacoustic.com software.)

    But I just got a new sub, and I'm in the process of looking at things again.

    If you do have a peak that large, an EQ can be a wonderful thing. And I agree with Wayne- do the sub first, but compare to the sub with mains. Remember, an eq isn't going to do much above the crossover freq either. And it can't do anything about dips. Just peaks.
     
  16. Martin Rendall

    Martin Rendall Screenwriter

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    Kevin,

    EQ's can fix dips. It depends on the dip, as it were. As long as it isn't a "null", boosting works. My system is all the proof I need.

    Martin.
     
  17. Wayne A. Pflughaupt

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    As they say, a picture is worth a thousand words. This one is courtesy of Sonnie Parker.


    [​IMG]


    Regards,
    Wayne A. Pflughaupt
     
  18. Rick_Brown

    Rick_Brown Second Unit

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    Joe Mihok, where did you get your BFD for $185 CAD?
     
  19. Martin Rendall

    Martin Rendall Screenwriter

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    Rick_Brown,

    You can find it for around that price at any Long & McQuade which have it in stock. But they all carry it, so at worst you need to order one. Phone around.

    Martin.
     
  20. Blaine_M

    Blaine_M Second Unit

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    So what exactly does the BFD do? Is it an eq? I'm a newbie here. Is there a test DVD out there that plays test tones in certain frequency ranges so I can adjust an EQ?
     

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