Problems with calculating an 8th order (SubSim)

[zoofelix]

Hello,
I am new here and I want to build an 8th order Subwoofer. I downloaded this program Subwoofer Simulator. I have the problem that I do not understand how it is ment with the ports. There is AV and LV. I think that AV is how wide the ports have to be and LV means how long they should be. They are given in "in". Does that mean inch? It sounds realy stupid to make a port which 1 inch wide ??? When I make it up to 4 inch wide, the port gets also a length wich is impossible to realize.. Can you plese help me with this problem? I think that Vb is given in liters, or not? I come from germany, thats why my English is not so good and thats also why I have the problem with the program. Here in Germany we use WinIsd because it is not as difficult. The main problem is that you can not calculate subs up to 8th order. But thats exactly what I want...

[simon5]

Yes Lv is the length of the port. Av I guess it's the area of the port or diameter ???

If you do a vented enclosure in SubSim and in WinISD, you could check what Av is by comparing both programs. You do a box of the same size with the same length of port Lv and then you'll find what Av is.

in = inches yes. In WinISD you probably saw that a larger port need to be longer to have the same tuning point. It's the same thing in SubSim.

If the program is made with all english units, Vb could be in cubic feet... again double check with a sealed box of the same size in WinISD and SubSim.

Good luck!

[BassAwdyO]

whoa whoa 8th order! Where do I find this program?

[kelticwizard]

Here.

Written by our own member, F4ier.

You should be aware that in sealed and ported systems, where the cone is on the outside of the enclosure, the response is shown to fall off quickly because the program was written not to reflect the decoupling of the cone at upper frequencies.

It is a very useful tool, giving you sims for impedance, impedance phase, and just a host of other things.