Today I learned about enclosure orders.
A standard bass reflex is considered a 4th order.
I learned that the bass roll off arguably defines the order of the enclosure.
Would this passive radiator represent a higher order enclosure? Because of its steeper roll off?
Passive radiator acts like a port, still 4th order. Additionally, roll off could be altered by changing tuning frequency, but it's still 4th order. I can alter the roll off a sealed enclosure by making it really big or really small - still 2nd order. The shape of the curve and roll-of on a 4th order bandpass can also be altered by changing tuning frequency. In the case of bandpass it's possible to have 2 different roll offs.