How to make my sub have tighter bass!!

Discussion in 'Archived Threads 2001-2004' started by Kim Bemis, Nov 18, 2002.

  1. Kim Bemis

    Kim Bemis Auditioning

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    I have a Definitive PF18 18 inch subwoofer and a Atlantic Technology 12 inch sub. The Atlantic is an acoustic suspension sub while the PF15 is ported. If I used polyfill in the PF18 would that make the bass tighter? Any suggestions would be appreciated!! Thanks to all replies!!
     
  2. Derek1

    Derek1 Agent

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    First I would look at what you are using for a sub cable. Better subwoofer cables can really help in tightening up the base.

    I switched my noname sub cable with a kimber PBJ and the bass became much tighter. At fist I was a little dissapointed because there seemed to be less bass than with the other cable but after listening back and forth.I discovered that although there seemed to be less bass it was due to the fact that the Kimber was removing much of the boomy unrealistic sound from music. The end result was a tighter cleaner more realistic sounding subwoofer.
     
  3. Wes

    Wes Screenwriter

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    My brother has the Definitive PF18 and I am sure unhappy with the port noise from this sub. If it were me I think I would pull the speaker and amp out and build a better box with a round port.
    Just my thoughts!

    Wes
     
  4. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I've found packing a sub with polyfill will tighten up the bass, but then it appeared that I lost some SPL and the sub wasn't "boomy" and loud as before.
    Remember that some ppl like some degree to boominess. [​IMG]
     
  5. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    Try to relocate it. The "boomy bass" has often little to do with the sub itself and more with the room modes or resonances.

    If it is in a corner there is your problem, try to move it more to the center of the wall.
     
  6. Wayne A. Pflughaupt

    Moderator

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    Kim,

    Let’s cut to the chase. In most home theater environments, the best low frequency response will come from matching subs that are placed in the same corner, and then precisely equalized with a parametric equalizer (equalizing eliminates that “boomy” problem Manuel mentioned). This arrangement more oft than not results in the highest SPL levels, the lowest extension, and of course the smoothest response. You can get acceptable (but not excellent) response by experimenting with out-of-corner locations, but the trade-off will be less extension and/or output. Separating the subs is definitely a no-no - typically results in ragged response, with maximum output further lowered.

    Thus you have a major problem here, Kim: Mismatched subs. Here’s an example of what you can get.

    Let’s say one of your subs is flat down to 20Hz, and drops 12dB/octave below that point. And let’s say your second sub is flat to 30Hz and drops 18dB/octave below that point. In addition, the second sub has a sag in response at 50hz that is 12dB deep.

    Now, if you were using only the sub that is flat to 20Hz, you would have excellent performance, right? But what do you get when you combine the output of these two subs?

    Overall output increases 6dB – that’s definitely good. However, now there is a 6dB sag in overall response at 50Hz. And response now starts dropping at 30Hz, as the range between 20-30Hz is now under-represented due to the fact that only one sub is putting out down there. Thus response at 20Hz is down at least 6dB, and falls out rapidly below that point – faster than 18dB/octave.

    I would take some in-room measurements with 1/6-octave sine waves and a SPL meter to determine which sub performs the best. Then either use that one exclusively, or sell the second and buy one that’s identical to the first. Things will drastically improve – especially after you equalize.

    Regards,
    Wayne A. Pflughaupt
     
  7. Chu Gai

    Chu Gai Lead Actor

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    how does the Kimber cable know which part of the signal it receives is responsible for the unrealistic sound and boominess and which part is music?
    Wayne's and Manuel's suggestions sound rather reasonable.
     
  8. John F. Palacio

    John F. Palacio Supporting Actor

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    I'll second's Mr. Gai's opinion.

    Best regards.
     
  9. Phil_DC

    Phil_DC Stunt Coordinator

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    John H Second Unit

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