Passive radiators and bass reflex
Sometimes adding passive radiators or bass reflex can improve perfomance
The design-in of a passive radiator (also often named as a slave unit) in a Speaker System can improve the low frequency response performance, also referred to as the bass sound reproduction.
This technique uses the tuning of a resonator to have its resonance just below the resonance frequency of the active driver itself and thereby adding more acoustic sound pressure level in this region.
This tuning is controlled by the moving mass, the mechanical compliance, the piston area of the passive radiator and all in combination with the size of the air volume inside the speaker system.
Obviously, all acoustical power comes from the active driver, and therefore the driver will be stressed maximum having a very high diaphragm displacement/stroke at the tuned frequency.
Ole Wolff has the capability of designing the active drivers and passive radiator having the robustness needed for these designs.
Ole Wolff uses a custom designed test rig to test and develop passive radiators