my calculations

Ive been learking around here for a month or so and ive been doing alot of reading. ive tryed to do the calculations myself and i think ive done ok but would some one go over them for me?

The sub im using is the vibe exact 8 inches.

T/S parameters from the vibe web site:

Qts:  0.475

so my  calculations are:

Vb:  1.909 Ft3

Min port dia. 2.25 inches

port dia. hoping to use 2.5 inches

so vent length using 1 port will be  5.68 inches.

hope im right

many thanks

gav

You are porting this little sub.  The box tuning (Fb) cannot be that much lower than the Fs of the sub.  You have 37 Hz listed as Fs, so tune your enclosure so that the Fb hits at about that point, or just one or two Hz above or below it.  You can go above it as much as you want, for example if you want to hit loud at 50 Hz (car freq.) tune your box there.

The Fs is the point of a speaker where it hits resonant frequency.  This is considered the lowest Hz the speaker will play.  This is not a problem if using a sealed box, but when porting it can be a problem if you have the box frequency (tuning freq. or Fb) too low.  The speaker will over-excurt and be damaged.