Announcement

Collapse
No announcement yet.

Calculating a slot port

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Calculating a slot port

    I have never tried a slot port and would really like to try it. Is there a software package to calculate this?

  • #2
    Bassbox 6 Pro does the calculations although I've read on this forum that there can be issues. I think that Tom Zarbo experienced a problem with one of the two subs in a build article that he published. Tom?

    Comment


    • #3
      its basically the same as a round port. The cross sectional area x length. IE a 4" id port is 12.5 sq in. A slot port of 2 x 6.25" would be the same length. There are other considerations and a slot port does have some frictional loss (more surface area) but for the most part they are the same.
      https://www.facebook.com/Mosaic-Audi...7373763888294/

      Comment


      • #4
        It depends on the slot dimension. If the width to height ratio isn't more than 6:1 or so it models the same as any port. It's when that ratio gets quite high the zone of high friction between the port air mass and longer port walls becomes very large compared to the port area, in effect reducing the port area. That lowers Fb and increases port velocity. The former can be addressed with a shorter duct, but the latter cannot. That makes a high aspect ratio slot port more of a liability than an asset.
        www.billfitzmaurice.com
        www.billfitzmaurice.info/forum

        Comment


        • #5
          Originally posted by billfitzmaurice View Post
          It depends on the slot dimension. If the width to height ratio isn't more than 6:1 or so it models the same as any port. It's when that ratio gets quite high the zone of high friction between the port air mass and longer port walls becomes very large compared to the port area, in effect reducing the port area. That lowers Fb and increases port velocity. The former can be addressed with a shorter duct, but the latter cannot. That makes a high aspect ratio slot port more of a liability than an asset.
          Bill, is that a typo? A smaller port of the same length will increase Fb - raise the box tuning. Or am I reading your post wrong, not understanding?

          Comment


          • #6
            Originally posted by Millstonemike View Post
            A smaller port of the same length will increase Fb - raise the box tuning.
            Are you positive ?
            "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
            exactly a Fc 3K for both drivers, anybody can do it." -Xmax

            Comment


            • #7
              Two identical (size) boxes, one has a 2"id port, the other 3".
              To get the same tuning (Fb), the larger port also needs to be longer.
              If they're both the same length, the smaller one will have a lower Fb/F3.

              Comment


              • #8
                Originally posted by Chris Roemer View Post
                Two identical (size) boxes, one has a 2"id port, the other 3".
                To get the same tuning (Fb), the larger port also needs to be longer.
                If they're both the same length, the smaller one will have a lower Fb/F3.
                Your right, I was thinking shorter port not smaller port.

                Comment


                • #9
                  The second thing that goes is your memory. The first is...I don't remember.
                  www.billfitzmaurice.com
                  www.billfitzmaurice.info/forum

                  Comment

                  Working...
                  X