 In both cases, the tuning affects the lower end of the driver's response but above a certain frequency, the driver itself becomes the dominant factor and the size of the enclosure and ports (if any) become irrelevant.In general, acoustic suspension systems (driver + enclosure) have a second order acoustic (12 dB/octave) roll-off below the -3 dB point.Bass reflex designs have a fourth order acoustic roll-off (24 dB/octave).