SVS (the source of this quote) make both ported and sealed subs:
"Sealed subwoofers typically have a smaller overall cabinet size and footprint, allowing easier integration into the listening environment with minimal visual impact to the décor. The reason for this is sealed models rely on the natural acoustic suspension of the sealed enclosure to control the woofer’s motion, rather than needing extra internal volume and a tuned port to boost low-end output. This design trades off a bit of raw efficiency for tighter, more articulate bass and a much smaller footprint—perfect for rooms where space is at a premium or for setups where sleek, low-profile gear is the goal. Whether you’re squeezing one behind a sectional, under a desk, or into a minimalist home theater, sealed subs deliver deep, musical bass without the bulk, blending performance with lifestyle-friendly design.
Best for Critical Music Applications
A properly designed sealed subwoofer will typically exhibit less phase rotation, lower group delay, and reduced ringing in the time domain. Sealed cabinet subwoofers are generally more accurate in frequency response and better at rendering instrumentals in a convincing way. These characteristics make the sealed subwoofer a natural choice for critical music applications and are typically described by enthusiasts as sounding tighter and more articulate or musical, with less perceived overhang."
