Home Forums DIY Speakers and Subwoofers Air velocity and chuffing Reply To: RE: Air velocity and chuffing

  • 123toid

    Administrator
    October 20, 2019 at 4:34 pm

    @dklexx1980

    There’s a few reasons why you won’t hear a hard and fast rule.  I’ll give a few reasons why.

    1.  If you look at the graph in WinISD you will notice that the speed of air is directly related to the frequency at which it is playing.  Keep this in mind.  If you plan to cross it over by 80hz, you can simulate that filter in WinISD, which will lower your air velocity considerably.

    2. Since it is frequency dependent, some people are less concerned about lower frequency 30hz and below.  Some of this is dependent on the use of the speaker.  If you are designing it for use of Home Theater full range tower, you will be more concerned, as you will probably get a lot more power going through it in quick burst.  Where this may not be as big of any issue depending on your music preference.

    I typically shoot for 17m/s, especially if doing a theater build.  One way to get around this is to have a huge roundover.  You are typically looking at something like a 1 1/2″ roundover bit depending on the size of the port.  And this roundover would be on both sides of the port. 

    Honestly, simulation can only get you so far.  You may need to create a test box to test different ports and or roundovers to see which you prefer with your specific setup.  Of course, if you have an exact model in mind or graphs for us to look at, we would definitely take a look at them. 


    Reply To: RE: Air velocity and chuffing