What makes a subwoofer sound boomy?

Discussion in 'Speakers' started by EdNichols, Apr 5, 2004.

  1. EdNichols

    EdNichols Second Unit

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    How does sub. design make it sound boomy? Is it stuffing too large a driver in too small a cabinet? Too much amperage? What?
     
  2. Edward J M

    Edward J M Cinematographer

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    Poor room acoustics causing an emphasis in the 40-60 Hz region.

    A poor FR from the sub itself, with an inherent emphasis in the 40-60 Hz region. High distortion from the sub can also add audible harmonics in this bandwidth.

    A wooden floor over an open space (like a basement), which can flex and resonate and add sound.
     
  3. Phil Iturralde

    Phil Iturralde Screenwriter

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    And to add to Edwards list, ...

    1) to 'much' Sub Level (not calibrated), ... and possibly, ...

    2) the frequencies shared between sub-woofer and main speakers.

    As a primer, read Stuart M. Robinson Sub-woofer Purchasing, Positioning and Calibration. on-line article where he points out ...
    Hope this helps,
    Phil
     
  4. Bhagi Katbamna

    Bhagi Katbamna Supporting Actor

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    Agreed. One of the reason that people recommend putting subwoofers in the corner is that they excite the most resonances in that position. I had a +18 dB peak at 40Hz in my room and it sounded impressive initially but I realized that it was at the cost of true deep bass. Getting a parametric EQ has helped.
     
  5. EdNichols

    EdNichols Second Unit

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    Thanks for the info. I just moved my sub. to a corner position from a center wall location and the sub certainly sounds louder. I haven't done a check with the meter to see if I have any problem at certain frequencies. BTW, I have a DVD that does a frequency sweep but where can I get one that plays and holds at certain frequencies? Also, if I have peaks at certain frequencies what would be an acceptable peak as compared to other frequencies?
     
  6. Ned

    Ned Supporting Actor

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    That's what my current location is like. If I was to move to the basement below would the problem still exist since the resonating floor is just above now rather than below?
     
  7. Felix_H

    Felix_H Stunt Coordinator

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    I fixed this problem by placing my sub on a slab of concrete. Bass is much tighter and clear and the boominess is gone.
     
  8. Edward J M

    Edward J M Cinematographer

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    Ned, if you moved the rig to the basement, the bass would probably tighten up considerably.

    The air pressure would not be enough to flex the wooden ceiling in the basement; it is the direct reactive forces of the woofer which create the floor boom.

    I agree with Felix - an A/C paver for $10 should help considerably to decouple the sub from the floor. If you want something fancier, I'll put you in touch with someone who makes them from marble.
     

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