2-4" vents vs. 1-6" vent?

Discussion in 'Archived Threads 2001-2004' started by jeff lam, Jan 11, 2002.

  1. jeff lam

    jeff lam Screenwriter

    Joined:
    Jun 4, 2001
    Messages:
    1,798
    Likes Received:
    0
    Location:
    San Jose, CA
    Real Name:
    Jeff Lam
    I ran over my tempest sonotube ideas over to Dan at Adire and he said:

     
  2. Fred Seger

    Fred Seger Stunt Coordinator

    Joined:
    Aug 13, 2000
    Messages:
    136
    Likes Received:
    0
    For what it's worth here's my two cents.
    I think two four inch vents is plenty, especially considering they are flared. And you won't notice any difference in the sound. Actually two straight four inch ports or one straight six inch port would probably suffice.
    Source's for 6 inch ports
    http://www.lightningaudio.com/nosoun.../products.html
    http://www.tune-town.com/Products/Ro...stallation.htm
    As far as the size goes, I think you could cut a foot or two off that sub and still have a great sub.
     
  3. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    I don't think you would hear the difference between two flared 4" ports and one straight or flared 6" port. However, a straight 6" port can be done from just plain PVC pipe which will be a fair bit cheaper than two of those FP4 flared port kits.
     
  4. Neil Joseph

    Neil Joseph Lead Actor

    Joined:
    Jan 16, 1998
    Messages:
    8,332
    Likes Received:
    1
    Real Name:
    Neil Joseph
    I was originally comparing two 4" ports for my DIY sub but I changed the design for a single 6" port which not only has more surface area but simplifies the construction process because only 1 port hole must be made in the endcap.
     
  5. jeff lam

    jeff lam Screenwriter

    Joined:
    Jun 4, 2001
    Messages:
    1,798
    Likes Received:
    0
    Location:
    San Jose, CA
    Real Name:
    Jeff Lam
    True, it will be much easier to cut only 1 port hole as opposed to 2. Besides I think 1 port will look better than 2 anyway.
    Anyway, what about the size of the enclosure, is there any way I can cut down on the size by about 1ft or so?

    At 18" and 6ft tall, it gives me over 10ft^3. Is it possible to get simmilar results from a shorter tube?
     
  6. Patrick Sun

    Patrick Sun Moderator
    Moderator

    Joined:
    Jun 30, 1999
    Messages:
    38,718
    Likes Received:
    463
    You're going to have model shorter tubes (find the volume of each, say, 3" section of tube takes up and subtract off the volume and model those new enclosure volumes) and see where that point is that will diminish low end performance.

    What's the point in using a Tempest if you shave off too much enclosure volume and wind up with a F3=30Hz. I would venture to say that 8 ft^3 is probably going to be the break-even point. Any lesser than that, and you'll better off using a different driver.

    Also, go with the 6" port (don't even need to flare it, it's plenty wide enough).
     
  7. Gil D

    Gil D Supporting Actor

    Joined:
    Mar 15, 1999
    Messages:
    577
    Likes Received:
    0
    Jeff,

    18" tube 5'tall is more in line with the 214L (7.510ft^3)Adire alignment. A little less extension than the EBS design but still plenty of output from what I hear from Dan W. This is what I am going with.

    Gil
     
  8. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Double check the actual diameter of your sonotube. My 18" was actually more like 18.75" inner diameter. My calculations gave a 5'2" tube with a Tempest and a 24" long piece of 6" section 40 PVC pipe inside it a net volume of 260L. Add 3" of end cap and 6" (4" would work too) of leg and you get 5'11" for the total height.
     

Share This Page