One of the most difficult questions that arise when calculating a box is the required net volume that suits your dynamics. To calculate the volume of the box, only three values are needed: the size of the speaker, the resonant frequency, and the total q-factor. It is worth considering that the parameters given by the manufacturer are approximate parameters of this model, and not specifically your speaker.
1. Fs — Resonant frequency frequency of the main resonance of the speaker without any housing. Characterizes only the speaker itself, not the finished speaker system based on it. When installed in any volume, it can only increase.
2. Qts — full q-factor dynamics, a dimensionless quantity that characterizes relative losses in dynamics. The lower it is, the more the radiation resonance is suppressed and the higher the resistance peak on the impedance curve. When installed in a closed box increases.
3. Vas — equivalent volume dynamics. Equal to the volume of air with the same stiffness as the suspension. The stiffer the suspension, the smaller the Vas. At the same stiffness, the Vas increases with the increase in the area of the diffuser.
4. Qms - Mechanical q-factor
5. Qes Electrical q-factor
Fc Resonant frequency of the speaker system
Qt - full quality of the acoustic system - optimally 0,71
Fc =√ 1+Vas/Vbox = Fs * Qt / Qts