View Full Version : Calibrating a box calculation software

02-25-2004, 09:28 AM
Hi All,

sometimes I wonder, that port dimensions, written in this forum, differ from values that I calculate with LSPCAD from Íngemar Johannson, Sweden.
So help to calibrate my (or your) system.

Let's take a virtual box with:
200 liters (or 7 ft³),
fill = 5% ,
a JBL 2245 speaker and
one port
and let us try what you all find out for the ideal port for getting the lowest possible frequency at -6dB (if 200 Hz are 0dB)

very curious bout what you find out. :confused:


02-26-2004, 03:27 AM
Originally posted by Hofmannhp
Hi All,

very curious bout what you find out. :confused:


ok.....silent forum...:confused:

I post my calculations for the above shown parameters:

ideal port for the box is calculated with

port diameter 6" / 15.2cm
port lenght 6-1/4" / 16cm
port area 182.4 cm²

-6dB point at 30.8 Hz

linear down to 49.6 Hz +- 0.2 dB