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2.5ft^3 of air space for Brahma 15, Port or Seal?

Discussion in 'General Car Audio Discussions' started by Bobby12many, Nov 29, 2002.

  1. Bobby12many

    Bobby12many Guest

    Well, I just planned out my next box in my Z and the resulsts show me that I have exactly 2.49 cubic feet of interior volume after all bracing and basket displacement. Now I am a true easy listener; I listen to Floyd, the Eagles, and Jazz. Although every now and then I like to bump out to some techno and Beats. Now will 2.5 feet be a tad on the small size to port a B15? I wwant to make sure that they are as tight and accurate as my two Alpine type R 10s were, yet hit harder. (Type Rs were in .9ft^3 seeing 200w a piece.) Would I be better of just sealing them off and going for all out sound quality, or is porting in this amount of airspace going to be a good investment in extra time and the small loss of tightness?

    BTW the Brahma will be seeing ~1200wrms
     
    Bobby12many, Nov 29, 2002
    #1
  2. sandt38

    sandt38 Full Member

    I'd like to see bigger sealed space. I would definately not port a B15 with 2.5 feet. Heck, I think my enclosure takes up 2.5 feet and it is a B12. Trust that a B15 sealed is not just all out SQ, it is PLENTY loud.
     
    sandt38, Nov 29, 2002
    #2
  3. Bobby12many

    Bobby12many Guest

    Sandt, you think I should do a little poly-fill in my enclosure then @ 2.5ft^3 sealed? :ph34r:
     
    Bobby12many, Nov 29, 2002
    #3
  4. BlkX

    BlkX Full Member

    Keep it sealed, i've heard Sandt's, and its all you want.
     
    BlkX, Nov 29, 2002
    #4
  5. sandt38

    sandt38 Full Member

    Yes, 3 pounds. 2.5 minimum. Not sure that it will affect the Brahma, but what the hell. It is a cheap bit of experimentation.

    I have found it works in some enclosures, but not others (most likely sub dependant)...
     
    sandt38, Nov 29, 2002
    #5
  6. Bobby12many

    Bobby12many Guest

    :D How is this lookin? I am a tad concerned about the 1.75" space between pole vent and box. But if there is polyfill in the box, would this really matter? This is going to be of plain jane of a box as they come.
    [​IMG]
     
    Bobby12many, Nov 29, 2002
    #6
  7. sandt38

    sandt38 Full Member

    3 pounds of fill. That is 2.77 feet, before displacement. Around 2.57 after sub displacement, and now we need bracing. Should do well. I do have a suggestion, to gain some space...

    [​IMG]

    INVERT THAT SUCKER
     
    sandt38, Nov 30, 2002
    #7
  8. Bobby12many

    Bobby12many Guest

    I think I may have to do that Sandt. Thanks a ton as always for being so helpful with this thread. Hopefully I will have enough room to invert that behemoth.
     
    Bobby12many, Nov 30, 2002
    #8
  9. geolemon

    geolemon Full Member

    Well, the Brahma has only like a 1" vent in the back, so technically you only need 1" of clearance behind it...
    1.75" should be completely fine.

    If you have enough room in front of the sub to invert the Brahma, you could alternatively make a ring out of MDF to mount the sub to, a spacer, which would buy you another 3/4" (or 1.5".. or 2.25"..etc) of rear clearance.

    If you aren't worried about taking up more space in your trunk though, the rear of the sub is definitely the more impressive side to look at, IMO! B)

    But you aren't forced to go down that road with your current box design at all.
     
    geolemon, Nov 30, 2002
    #9
  10. Bobby12many

    Bobby12many Guest

    Geo- Are there any Ill effectsto the performance of the driver If I were to make a 2" spacer out of birch to raise the Driver out of the box a tad?
     
    Bobby12many, Nov 30, 2002
    #10
  11. sandt38

    sandt38 Full Member

    None bud. It will work just fine.
     
    sandt38, Nov 30, 2002
    #11
  12. Bobby12many

    Bobby12many Guest

    Ill let you guys know how it came out and post some pics and stuff next week. I appreciate all of your help!
     
    Bobby12many, Nov 30, 2002
    #12