SVS — “Sealed vs. Ported Subwoofers”
Subwoofer-maker SVS argues its own catalogue: the company sells both alignments, and the piece is written to keep a buyer from ruling either one out. Read it as a vendor explaining a tradeoff it has a stake in on both sides — which is why the reasoning is usable even where the recommendation is marketing. T3 (manufacturer blog, no measurements published in the post).
What it claims
- Sealed gives “less phase rotation, lower group delay, and reduced ringing,” in a smaller cabinet, and pairs well with room-gain in small and mid-size rooms — the gentle rolloff and the room’s rise meet in the middle.
- Sealed costs output. In the deep octaves (roughly 18–36 Hz) it needs EQ boost to keep up, and the boost eats amplifier power. Ported reaches 2–4× the peak dynamic output down there for the same money in the same product family.
- Ported wants a bigger box (cabinet volume plus port area), and adds phase rotation and group delay near tuning.
The part worth keeping
SVS pushes back on the standard “sealed for music, ported for movies” split, and the argument is a real one rather than a slogan: if a ported box is tuned low enough (≤20 Hz), the phase rotation lands below the music bandwidth, and the sealed and ported group-delay curves converge above 30 Hz. So the tightness penalty is a property of the tuning frequency, not of having a port. A 40 Hz-tuned sub and a 16 Hz-tuned sub are not the same argument.
That reframes the spoke’s existing sealed-vs-vented tension (loudspeaker-enclosure): the knob is where you tune, and how much box you’ll accept to tune there.
Caveats
No measured curves, no models named, no test conditions. The 2–4× output figure is stated, not shown, and “converge above 30 Hz” is exactly the claim a port vendor benefits from. Treat both as hypotheses this spoke has not yet checked against a third-party measurement.
Related
loudspeaker-enclosure · group-delay · room-gain · passive-radiator · thiele-small-parameters · synthesis