What are the other specifications a passive radiator has?
Passive radiators have a Fs, Cms, Mms, Qms, and Vas just like a typical driver. Sometimes these are stated as Fp, Cmp, Mmp, Qmp, and Vap respectively for the PR. The most important thing to realize with these specifications is that the Cms, Qms, and Vas should be as large as possible. This is when the passive radiator acts closest to a port of the same diameter. The other important specification is the Mms of the passive radiator as that is what will determine the tuning frequency of the cabinet.