Vented box car subwoofers

Vented box

— the case of such a subwoofer has a phase inverter — a tube or other structural element that connects its internal space with the outside world. The length of the phase inverter is chosen so that the sound waves passing through it are superimposed in a special way on the waves from the diffuser. The advantages of bass-reflex cases are good sound characteristics with small sizes, the disadvantages are the tendency to extraneous noise in the bass-reflex.