I am just designing a box for my 4x PA460's with WinISD. Now, this might seem like a bit of a dumb question to some, but I'll risk asking it anyway haha.
Is it best to design the box based on GROSS volume (still including driver, port & bracing volumes), or to base it on the NET volume after driver, bracing and ports (I'll get to this in a sec)
are subtracted. If this is the case, then won't the port length be directly affected by the space occupied BY the port, and the length then need to be recalculated after working out the space occupied by the port, ending up in a never ending adjustment of figures?
The GROSS box volume is 200L,
The driver occupies 9.138L,
The bracing occupies say 5L,
So now the net volume (excl. port as is yet uncalculated) is 185.862L.
You then calculate your port length based on this volume and so for a 150mm PVC pipe port tuned to 23Hz that comes out at a port length of 42.80cm. Ok.
So my question is: Is the port length correct at this point then?
OR, do you now subtract the port volume of 7.869L (153mm o/a port diameter) from your box volume and get a NET VOLUME of 177.993L.
But hey, now your box volume is 7.869L less than what you calculated your port length off originally!?
Do you recalculate the port length with this new box volume of 177.993L? But if you do that, then your port will now be longer to compensate for the now smaller box volume. And then you need to recalculate again >>> and you then end up in a vicious cycle between box volume and port length adjustments and you can never getting it exactly perfect! *sigh*
I hope you can follow me on this one... Can anyone bring me some clarity and peace of mind?