From post 1
SVS SB-4000 Subwoofer: Sealed Cabinet
o 19Hz - 310Hz +/-3 dB
SVS PB-4000 Subwoofer: Ported Cabinet
o 16Hz to 200Hz +/-3dB (standard mode)
o 13Hz to 200Hz +/-3dB (extended mode)
o 18Hz to 200Hz +/-3dB (sealed mode)
Span specifies the range between the start and stop frequencies. Google it. You learn something new ever day. Ported goes to lower frequencies.
In a sealed box, the pressure in the cabinet resist the driver structure from being in anyplace other than its static position. An outward movement...
In a well made sub; to me "Sealed" is a compromise you make to get a smaller size unit. If you push it hard, "Sealed" is hard on the speaker cone's suspension. And with the restrictiveness, you lose volume and frequency spans. Momentum resistance is faster though because the pressure of the...