Sealed, 8 Inch

Sealed 8 Inch Subwoofer Boxes

Sealed cabinets for 8 inch drivers, standard and wedge, with the net volume on every card. CNC-cut in Tullahoma.

Sealed 8 inch Proline X subwoofer enclosure

Sealed, 8 Inch

A sealed 8 inch subwoofer box is the alignment that trades a little output for control: the trapped air behind the cone acts as a spring, roll-off is gentle, and the cabin's own gain below 45 Hz fills in what the box gives up. Every cabinet on this page is cut for a 8 inch driver, and the listing states the net volume, which is the only number a sealed box is really about.

An eight is the size you choose when the space is the constraint, and the only size where we build a quad cabinet. CNC-cut in Tullahoma, Tennessee from Langboard Elite MDF on our own ShopSabre routers, polyfill installed. We run the machines.

Sealed 8 inch cabinets in stock today | single, dual, triple and quad | standard and wedge | Performance and Performance Optimized | polyfill installed

Cut, assembled, carpeted and shipped from our own shop in Tullahoma, Tennessee. Stock counts on every card are shelf counts. Every sealed cabinet ships with polyfill installed. Limited warranty runs by series from the original date of purchase: one year on Performance and Performance Optimized.

Specified and written by Scott Welch, IASCA National and MECA World Champion, who runs the CNCs these are cut on. Figures come from our own build sheets and the driver manufacturers' published parameters.

Decision Shortcut

Find Your Match

Curated picks matched to common build goals

Best Value

Proline X Performance P8-S Sealed Enclosure for 8-inch Subwoofers

Proline X

Proline X P8-S | Single 8" Sealed Subwoofer Enclosure | V2

P8-S Single 8" Sealed Subwoofer Enclosure. The lowest-priced sealed 8 inch cabinet on the page, standard orientation, 0.4 cubic feet net.

$ 94.00

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Best for Trucks

Performance Optimized Series PO 8D-S W XL speaker enclosure by Proline, featuring a black frame with two circular openings, shown on a dark blue background with dimensions labeled 32 inches wide and 11 inches deep.

Proline X

Performance Optimized Wedge Sealed Dual 8" Enclosure | PowerBass XL-844

PowerBass XL-844. A wedge cabinet tapered to sit flush against a seat back.

$ 229.99

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Shallowest Cabinet

Proline X placeholder graphic reading Photos Coming Soon over a United States flag, product photography pending.

Proline X

Proline X Performance Optimized Wedge Enclosure | Fits Kicker Solo X 8" Subwoofer

Performance Optimized Wedge cabinet that fits Kicker Solo X 8" Subwoofer. 10 inches deep, among the shallowest sealed 8 inch cabinets in stock, for openings a standard box will not take.

$ 299.99

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Most Airspace

Two car audio (1 black & 1 grey) subwoofer enclosures with visible brand logo on a white background

Proline X

Proline X P8-S | Single 8" Sealed Subwoofer Enclosure | V3

P8-S Single 8" Sealed Subwoofer Enclosure. 0.5 cubic feet net, among the most air behind an 8 inch cone in a single-driver cabinet on this page, for drivers that want a large sealed volume.

$ 129.99

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Sealed or Ported at 8 Inches

Same driver size, same shop, same materials. The alignment changes the cabinet, what the listing has to tell you and what you do at the amplifier. This page is the sealed half; the ported 8 inch page is the other.

Sealed and ported 8 inch Proline X cabinets as built, 5 September 2026.
Sealed 8 inchPorted 8 inch
Net volumeSmaller for the same driverLarger, with the port's own volume added
PolyfillInstalled on every buildNone. Ships dry so the tuning holds
Tuning statedNo, a sealed box has noneYes, on every listing
OutputFlat passband, gentle 12 dB per octave roll-offMore output around tuning for the same power
Subsonic filterAn improvementA requirement, set just under tuning
Pick it whenSpace is tight, music is wide, or you want a dualThe space is there and output per watt matters

Shared across both: Langboard Elite MDF at 48.5 lbs per cubic foot, 200 psi internal bond and 410,000 psi MOE, cut on ShopSabre routers in Tullahoma and carpeted in house.

What a Sealed Box Does for a 8 Inch Driver

Sealed is the alignment, not the shape. The air inside the cabinet is a spring the cone works against, so the smaller the box the stiffer the spring and the higher the system Q. An eight in the right sealed volume sits near a Qtc of 0.7: flat through its passband, rolling off at 12 dB per octave below resonance, which the car's own transfer function then lifts back. That is why a sealed eight sounds bigger in the vehicle than the chart suggests.

The number that matters is net volume, and it is on every listing here, running 0.4 to 0.5 cubic feet for a single-driver cabinet across the page. Driver-matched builds are cut to one driver's published parameters. Universal-cutout cabinets are sized for the range a typical 8 inch driver wants, and take any eight whose mounting depth clears the cabinet.

Every sealed cabinet we build ships with polyfill installed. It slows the air behind the cone, which makes the box behave as if it were slightly larger, and it is already done for you.

How to Choose a Sealed 8 Inch Enclosure

Start from the driver

If we cut a cabinet for your driver, use that one: it is sized to the published parameters and the net volume is already right. If we do not, a universal-cutout cabinet on this page takes any 8 inch driver whose mounting depth clears, and the sealed box calculator in the links below tells you which volume it wants.

Read the net volume, not the outside dimensions

Net volume is what is left after the driver displacement and the bracing, and it is the number the cabinet was designed to. Two boxes with the same outside dimensions can differ by a third of a cubic foot inside.

Sealed or ported

Sealed is the smaller cabinet, forgives a wrong-sized car, takes single, dual, triple and quad configurations, and is the safer choice where the music is wide rather than low. If output around a single tuning matters more and the space is there, the ported 8 inch page is the other half of this decision.

Standard, down-fire or wedge

Pick the shape from the vehicle, not from the driver. A hatch or an SUV floor suits down-fire. A regular cab or a rear seat suits the wedge. A trunk with height suits a standard cabinet. The driver does not care which; the fit does.

Will a Sealed 8 Inch Box Fit

Three measurements decide it, and they are all on the listing.

Depth

Depth on this page runs from about 9.2 to 13 inches. Measure the space where the box will sit, not at the opening, because wheel wells, seat brackets and the taper of a trunk floor narrow it toward the back. A shallow-mount driver gets a shallower cabinet, which is why the same size differs by several inches from one card to the next.

Orientation

A standard cabinet fires forward and stands on its base. A down-fire cabinet mounts the driver on the bottom baffle and sits on feet that set the floor clearance. A wedge is tapered on the rear panel so it leans flush against a seat back, which is what makes it the truck cabinet. This page carries standard and wedge builds; the filters narrow it.

Driver count

Single, dual, triple and quad cabinets are on this page. A dual is two drivers sharing one cabinet; the listing states the net volume, so on a dual check whether the figure is per chamber or for the whole box. Two smaller drivers in one cabinet is often the better answer than one larger driver where height is the limit.

Two Shapes, Two Series

The page spans standard and wedge cabinets from the Performance and Performance Optimized lines, in single, dual, triple and quad configurations. Brands we cut sealed 8 inch cabinets for include Kicker; the card says whether we stock the driver as well, because the box is the product and it has to be right on its own.

Limited warranty runs by series from the original date of purchase: one year on Performance and Performance Optimized.

The straight cabinet

Standard 8 inch, sealed

single, dual, triple and quad, sealed·From $94.00

Fires forward, stands on its base. The shape for a trunk with height or a cargo floor with room behind the seat.

1 year limited warranty on Performance

Leans on the seat back

Wedge 8 inch, sealed

single, dual and triple, sealed·From $229.99

Tapered on the rear panel to sit flush against a seat. The truck cabinet, and the shape that leads at the larger sizes.

1 year limited warranty on Performance Optimized

Prices are the lowest in stock for each shape today. Depth, net volume and, on ported builds, tuning are what change from card to card.

Categories

Keep Reading

Supporting guides to help you design, build, and tune your system.

Sealed 8 Inch Box Questions

How big is a sealed 8 inch subwoofer box?

Net volume on this page runs 0.4 to 0.5 cubic feet for a single-driver cabinet, and every listing states its own. The driver-matched builds are cut to one driver's published parameters; the universal-cutout cabinets sit in the range a typical 8 inch driver wants. Net volume is what is left after the driver and the bracing, so read that rather than the outside dimensions.

Does a sealed 8 inch box need polyfill?

It is already in. Every sealed cabinet we build ships with polyfill installed, weighed to the volume of the box. It makes the cabinet behave as if it were slightly larger and damps internal reflections. Leave it as shipped.

Sealed or ported for a 8 inch sub?

Sealed is the smaller cabinet, forgives a wrong-sized car and is the safer choice for wide-ranging music. Ported gives more output around its tuning for the same power from a larger box and needs a subsonic filter. If depth or height is the limit, sealed. If the space is there and output matters, the ported 8 inch page is the other half of this decision.

Can I put a different 8 inch driver in one of these?

In a universal-cutout cabinet, yes, as long as the driver's mounting depth clears the cabinet depth on the listing and its recommended sealed volume is close to the net volume stated. In a driver-matched build the volume was solved for one driver, so a different one will work but will not be optimised.

Do you make dual sealed 8 inch boxes?

Yes. This page carries dual, triple and quad cabinets alongside the singles. The listing states the net volume; on a dual check whether the figure is per chamber or for the whole cabinet.

What is the warranty on a sealed 8 inch box?

Limited warranty runs by series from the original date of purchase: one year on Performance and Performance Optimized. It covers structural failure and manufacturing defects for the original purchaser.

Drivers Built to Match

8 Inch Subwoofers Spec'd for These Sealed Boxes

The drivers below are matched to the enclosures above by Thiele-Small parameters. Buying together guarantees the alignment, port tuning, and damping work the way the engineering intended.

Image Dynamics ID8 V4 8inch Subwoofer

Image Dynamics

Image Dynamics ID8 V4 8inch Subwoofer

$ 99.99
Prodigy Audio 8 inch Subwoofer NB2 Series - Prodigy Subwoofer for car audio systems

Prodigy Audio

Prodigy Audio 8 inch Subwoofer | NB2 Series

$ 108.99 $ 115.99
Image Dynamics IDQ8 V4 8inch Subwoofer

Image Dynamics

Image Dynamics IDQ8 V4 8 inch Subwoofer

$ 193.99
Arc Audio Arc Series 8 inch Subwoofer

Arc Audio

Arc Audio Arc Series 8 inch Subwoofer

$ 239.00

View all 8 inch subwoofers | Need a custom build? Contact us

Amplifiers for the System

Power for Your Subwoofer System

Monoblock amplifiers matched to the power requirements of the drivers these enclosures are built for. Buy the enclosure, match the driver, pick the right amplifier.

Prodigy Audio 1200 Watt Mono Block Amplifier NBM1200.1 - Prodigy Amplifier for car audio systems

Prodigy Audio

Prodigy Audio 1200 Watt Mono Block Amplifier | NBM1200.1

$ 272.99 $ 326.99
Wavtech Link5001Mini

Wavtech

Wavtech Link5001Mini

$ 299.99
US Acoustics Mike 1500w Monoblock Amplifier US Acoustics

US Acoustics

US Acoustics Mike 1500w Monoblock Amplifier

$ 329.99
Image Dynamics SQ600.1D 600W Mono Block Amplifier

Image Dynamics

Image Dynamics SQ600.1D 600W Mono Block Amplifier

$ 399.99

View all monoblock amplifier | Need a custom build? Contact us

Amplifiers for the System

Power for Your Subwoofer System

Monoblock amplifiers matched to the power requirements of the drivers these enclosures are built for. Buy the enclosure, match the driver, pick the right amplifier.

Rainbow Audio SL - M2 2 channel micro amplifier

Rainbow

Rainbow Audio SL-M2 2 channel micro amplifier

$ 89.99 $ 549.99
Rainbow Audio Dream 0.5K Mono Class D Amplifier

Rainbow

Rainbow Audio Dream 0.5K Mono Class D Amplifier

$ 89.99 $ 399.99
US Acoustics Lisa 4 Channel Class AB Amplifier 4 x 50w US Acoustics

US Acoustics

US Acoustics Lisa | 4 Channel Class AB Amplifier | 4 x 50w

$ 159.99
US Acoustics Wendy 2 Channel Class AB Amplifier 2 x 75w US Acoustics

US Acoustics

US Acoustics Wendy | 2 Channel Class AB Amplifier | 2 x 75w

$ 159.99

View all car amplifiers | Need a custom build? Contact us

Last updated September 5, 2026