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ported box for 2 15" audiopipes

Discussion in 'Subwoofer Box and Custom Fabrication' started by danracer, Aug 2, 2007.

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  1. danracer

    danracer Full Member

    i just want to make sure that the results on winisd where right:
    dimensions- H: 25 W:45 D: 18 thickness: 3/4 port tuned to 37 hz interior vol.: 9.761

    2 6" vents...vent lenght 7.84
     
    danracer, Aug 2, 2007
    #1
  2. Ranger SVO

    Ranger SVO Full Member

    Actually I am coming up with a slightly shorter port. Your internal volume is right on the money. But I keep coming up with a 6-3/4 inch port for two 6-inch diameter ports.

    I wonder why the difference. To compensate for port volume and speaker volume, I am making port calculations with only 9 Cu Ft. This should make the port even longer.

    Your port length of 7.84-inches with a box volume of 9.761 should put port tuning at 33.4 Hz.

    So I would go with 6-3/4 to 7 -inches on the length
     
    Ranger SVO, Aug 2, 2007
    #2
  3. danracer

    danracer Full Member

    ohh i think its because i gave you the original internal volume...what i did was that i decreased the internal vol by .7 because of the bracings, subs and everythin....the internal vol i used was 9.061
     
    danracer, Aug 2, 2007
    #3
  4. danracer

    danracer Full Member

    and that box tuned to 37hz gave me the port length of 7.84
     
    danracer, Aug 2, 2007
    #4
  5. Ranger SVO

    Ranger SVO Full Member

    The decrease in size does explain the difference. And you port lengths should be right for the smaller volume
     
    Ranger SVO, Aug 2, 2007
    #5
  6. danracer

    danracer Full Member

    okk...now a question about the building....what type of bracing should i use? what should I use as a port? is it better to use a router to cut the wood? which screws should i use? srry for all the question but this is the first box ill be making...thanks
     
    Last edited: Aug 2, 2007
    danracer, Aug 2, 2007
    #6
  7. danracer

    danracer Full Member

    [​IMG]
    can the ports be located like that??
     
    danracer, Aug 2, 2007
    #7
  8. danracer

    danracer Full Member

    hmm now im having a problem with the port length on Bassbox pro....i dont get why when i try to put 9.061 the port length comes out 5.643 in
     
    danracer, Aug 2, 2007
    #8
  9. danracer

    danracer Full Member

    [​IMG]
     
    danracer, Aug 2, 2007
    #9
  10. danracer

    danracer Full Member

    [​IMG]
    this are the subs parameters
     
    danracer, Aug 2, 2007
    #10
  11. Ranger SVO

    Ranger SVO Full Member

    I was using a calculator and a formula that I know. BassBox Is Much More Accurate and takes into account other things that we cannot. Now I would still go up to 6-inches.

    Also notice that BassBox is recommending a Sealed Box. I would still build a ported box Just Because they are cooler.

    Now for a previous question, I use course 2-inch drywall screws. I always predrill with an1/8th inch bit. The best material for ports is PVC.

    Now we will get some arguements here and most will be valid. I dont like too much bracing, just enough to get by. I do like to brace the Baffle board.
    Its hard to see in this picture

    [​IMG]

    but you should be able to make out the brace on the baffle board, there is another brace on the other side of the port. I like for the speaker to be mounted solid all the way around. There are no other braces in that box.

    That should start a debate.
     
    Ranger SVO, Aug 3, 2007
    #11
  12. danracer

    danracer Full Member

    is there a graph in bassbox to see the spl??
     
    danracer, Aug 3, 2007
    #12
  13. danracer

    danracer Full Member

    okk well i decreased the size a bit but still kept the 2 6" ports tuned to 37hz...the port length came out 8.966 but i guess it ill go down when i put the bracing measurements... ok so the bracing should be as tall as the box and a depth of about 4 inches?
     
    danracer, Aug 3, 2007
    #13
  14. danracer

    danracer Full Member

    should i put dampening material in the box?
     
    danracer, Aug 3, 2007
    #14
  15. Ranger SVO

    Ranger SVO Full Member

    I might put just a little in a ported box, but it needs to be glued down. I usually don't use any in a ported box.

    Finish designing the box and you will get to the graph screen. There will be a plot button at the end and it will make the graphs
     
    Ranger SVO, Aug 3, 2007
    #15
  16. danracer

    danracer Full Member

    well love Bassbox pro made the calculations a lot easier and gave me all measurements...thanx ranger... ill still be askin questions since this ill be my first build...well this is what i finished with: dimensions are- 22 tall, 45 wide, 16 depth...ports-2 dimensions 6 in. in diameter and 9.141 is the length. i added some bracings like the ones you have on that box: 20.5 tall, .75 wide and 4 in. depth...the box is tuned to 37 Hz, it has a peak of about 126dB im a little dissapointed i wanted to see at least 132 but i think that w/ the bass boost and all it ill increase a bit, you tell me...anyways thanx and if anything is wrong or weird please tell me
     
    danracer, Aug 3, 2007
    #16
  17. Ranger SVO

    Ranger SVO Full Member

    It will be louder in the car. What we wanna see is how much gain we have. Go to the Normalized Amplitude Response graph and look at the peak above 0. What we want is for the highest peak above 0 to match a frequency that Corresponds to the length of the vehicle. (i know I just said a bunch of sh!t that makes no sense)

    When you get a chance tell me what frequency its peaking at. For most SUVs it should be around 40 to 45 Hz. For most hatch back cars the peak should be closer to 50 or 55 Hz. Now this is peak frequency, and it has little to do with port tuning.

    If its in the trunk of a car we dont get as much cabin gain effect. So lots of power.
     
    Ranger SVO, Aug 3, 2007
    #17
  18. danracer

    danracer Full Member

    well it says 3.92dB/58.69Hz....well i have a mini van and it ill be in the "trunk"
     
    danracer, Aug 3, 2007
    #18
  19. danracer

    danracer Full Member

    soo that is really close to te hatchback...do u think i have to change the box a bit...cuz i have a minivan
     
    danracer, Aug 4, 2007
    #19
  20. danracer

    danracer Full Member

    well tomorow im gonna buy the wood and probably get all the materials ill need...what things do u recomend i use beside the drywall screws??
     
    danracer, Aug 4, 2007
    #20
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