which freq to tune ports to? read ahead...

Discussion in 'Home Theater Projects' started by Mike SJ, Dec 3, 2003.

  1. Mike SJ

    Mike SJ Supporting Actor

    Joined:
    Nov 10, 2003
    Messages:
    718
    Likes Received:
    0
    ok say I have a 4 cubic foot (128 liters) sealed sub with 2 10"s and I get a gradual increase in SPL from [email protected]'s to [email protected]'s. Should I increase the box dims and tune the port below 20Hz? or keep the same size and tune the port @ 20Hz? Suggestions please? and If you give one, please explain what the effect will be. thanks
     
  2. Ryan Schnacke

    Ryan Schnacke Supporting Actor

    Joined:
    Feb 5, 2001
    Messages:
    876
    Likes Received:
    0
    So you're seeing a 25dB increase from the tuning point at 20Hz to the upper end at 100Hz? Doesn't this seem like a lot of slope? I would probably raise the tuning point and/or enlarge the enclosure until I got more like 5 to 10dB of slope.

    I know that room gain will fill in the bottom end to some degree, but even with a really small room I wouldn't count on 25dB of room gain.
     
  3. Mike SJ

    Mike SJ Supporting Actor

    Joined:
    Nov 10, 2003
    Messages:
    718
    Likes Received:
    0
    "Doesn't this seem like a lot of slope?"

    Well yes, yes it does, that is why i am posting this question. So say I increased the box size to 6 cf or 168 liters, that would help with the 100Hz to 40Hz range and then if I ported it and tuned it to 20 Hz, then that would help in the 40Hz to 20 Hz range, right? of course all these are approximates.
     
  4. Brian Bunge

    Brian Bunge Producer

    Joined:
    Sep 11, 2000
    Messages:
    3,716
    Likes Received:
    0
    Without knowing exactly what drivers you're using, and their parameters, any suggestions we make are purely guesses. You really should give us the info. on the drivers if you want a more accurate answer.
     
  5. Mike SJ

    Mike SJ Supporting Actor

    Joined:
    Nov 10, 2003
    Messages:
    718
    Likes Received:
    0
    well winisd showd how well 2 3' long ports would do in the same size enclosure. it would flatten the whole thing to 30HZ then a easy rolloff to 15 Hz.

    so its just about right
     

Share This Page