What is the difference between a sealed and a ported subwoofer enclosure?

A sealed enclosure is a closed box that rolls off gently at 12 decibels per octave below its tuning point, which tends to measure flatter in a real room and suits music. A ported enclosure uses a tuned port to add 3 to 6 decibels of output near its cutoff, at the cost of a steeper 24 decibel per octave roll-off below that point and a larger cabinet.

Does subwoofer port position matter?

Yes. A front-ported subwoofer can sit close to a wall behind it without choking the port. A rear-ported subwoofer needs real clearance behind the cabinet or the tuning shifts and the port can chuff. A bottom-ported or down-firing subwoofer is sensitive to the floor clearance set by its feet or plinth. The port position should match where the subwoofer will actually be placed.

What is a passive radiator on a subwoofer?

A passive radiator is a second cone with no voice coil and no magnet that replaces a port in a sealed-style enclosure. Pressure inside the cabinet moves it the way a port's air column would move, adding output in a similar range to a port without the port's chuffing noise at high excursion, at the cost of the added expense of a real driver-sized part.

Subwoofer Enclosure Types: Sealed vs Ported vs Horn

Q: What is a horn-loaded subwoofer?

A horn-loaded subwoofer couples the driver to the room through a flared or folded acoustic pathway that dramatically increases efficiency, at the cost of a cabinet that can be extremely large for the output it produces. A tapped horn folds that pathway back through the driver's own rear wave to pack more horn length into a smaller footprint. Both are rare, pro-audio-derived designs built for maximum output rather than a small domestic footprint.

A subwoofer’s enclosure type is the single biggest factor in how it rolls off, how it integrates with a room, and how much it can weigh and cost for the same output. Across the 280 subwoofers ranked here that publish it: 103 sealed, 156 ported (split across four port positions), 18 passive-radiator, and a handful of rarer horn-loaded designs.

This page defines every enclosure type in the data. For the deep comparison between the two common ones, see best sealed subwoofers and best ported subwoofers, or the full case for each in the subwoofer buyer’s guide.

Sealed

A closed box. The driver moves air against the trapped pressure inside, with no port or radiator. Rolls off gently at 12 dB per octave below tuning, which is why sealed subs tend to measure flatter in a real room and suit music - the full explanation is on best sealed subwoofers.

103 of 280 subwoofers here are sealed.

Ported (Bass-Reflex)

A box with a tuned port that resonates near the driver’s low-frequency cutoff, adding 3-6 dB of output in that range at the cost of a steeper 24 dB per octave roll-off below tuning and a larger cabinet. Full explanation on best ported subwoofers.

156 of 280 subwoofers here are ported - the most common single category - and every one also records where the port fires, which matters for placement:

Front-ported (72) - the most flexible. Can go close to a wall behind it without choking the port. SVS PB-4000, Cadence Sound CSX-15 MKII.
Bottom-ported / down-firing (40) - fires into the floor, usually through feet or a plinth that sets a fixed clearance gap. Moving it onto carpet or changing the riser height can measurably change the tuning. Power Sound Audio XV30FSE, Outlaw Audio LFM-1 EX.
Rear-ported (31) - needs real clearance behind the cabinet, typically 6+ inches, or the port chuffs and the tuning shifts. The worst choice for a cabinet pushed against a wall. Wharfedale DX-1, RSL Speedwoofer 12S.
Side-ported (8) - a middle ground; needs lateral clearance rather than clearance behind or below. Yamaha YST-SW215, OSD SS8.

Practical rule: match the port position to where the sub is actually going. A rear-ported sub bought for a spot tight against a wall will underperform its own measurements regardless of how good the driver is.

Passive Radiator

A sealed-box variant where a second, undriven cone - no voice coil, no magnet - replaces the port. Pressure inside the cabinet moves the radiator the way a port’s air column would, adding output in a similar range to a port without the whistling or chuffing a port can produce at high excursion. The trade is cost and complexity: a passive radiator is a real driver-sized part, not a hole in the box.

18 of 280 subwoofers here use one as the primary enclosure design. Passive radiators also appear as a secondary feature on plenty of sealed and ported subs not counted in this figure - see speaker drivers explained for why a passive radiator isn’t counted as a driver at all.

Horn-Loaded And Tapped Horn

A horn couples the driver to the room through an acoustic transformer - a flared or folded pathway that dramatically increases efficiency, at the cost of a cabinet that can be extremely large for the output it produces. A tapped horn folds that pathway back through the driver’s own rear wave, packing more horn length into a smaller footprint than a straight horn.

Rare - one true horn and one tapped horn in this store, both from JTR/Danley-style pro-audio design lineages built for maximum output rather than domestic footprint: the JTR Orbit Shifter PRO (horn) and Danley Sound Labs DTS10 (tapped horn). These aren’t a mainstream home-theater choice; they exist at the extreme output end of the large subwoofer ranking.

In-Wall

Not an acoustic principle so much as an installation constraint - the enclosure is built to sit inside a wall cavity rather than in the room. Two records here (BG Radia BGX-S6B, ELAC IW-S10EQ) use this. Because the wall cavity itself becomes part of the enclosure, in-wall subs are far more sensitive to the specific installation than a freestanding box, and published measurements should be read as more approximate than usual.

Where To Look Next

Every subwoofer’s enclosure type and port position (where relevant) is in its spec table. For the full sealed-vs-ported argument, including why two smaller subwoofers usually beat one large one, see the subwoofer buyer’s guide. For how enclosure interacts with output at each frequency, see CEA-2010-A explained and dB / SPL output explained.

Last Updated August 08, 2026