Proline X PO 10-S DFW RSW sealed down-fire wide enclosure for the Alpine RSW10, 41 inches wide by 4.75 inches tall, feet add 1.75 inches of height.

Proline X PO 10-S DFW RSW sealed down-fire wide enclosure, end panel with side-mounted terminal cup, 4.75 inches tall by 12 inches deep.

Proline X

Performance Optimized Down Fire Wide Sealed 10" Shallow Sub Enclosure | Alpine RSW10

Q: Why is this cabinet 41 inches wide instead of 30?

Because it is only 12 inches deep. The standard Performance Optimized Down Fire platform is 30 wide by 15 deep, and under a rear seat or on a narrow cargo floor there is often not 15 inches to give.The airspace lost from the depth is recovered from the length, so the cabinet runs 41 inches instead of 30 and stands 4.75 inches tall, with the same driver specific chamber. If you do have 15 inches of depth, the standard 30 by 15 cabinet is the better pick.

Q: How does this compare to the standard 30 x 15 RS-W10 enclosure?

The standard cabinet is 30 by 15 by 4.75 inches and gives the driver 0.50 cubic feet net. This one is 41 by 12 by 4.75 inches and gives the driver 0.539 cubic feet net. Here the height is set by the 3.25 inch motor's clearance rather than the airspace, so the wide box carries more air, which lowers Qtc slightly.The choice is about shape: the standard box if you have 15 inches of depth, this one when depth is the limit and you have 41 inches of run.

Q: Should I choose the RS-W10D2 or the RS-W10D4?

In 0.539 cubic feet net the RS-W10D2 lands at Qtc 1.457 with Fc at 46.0 Hz and F3 at 32.3 Hz, and the RS-W10D4 at Qtc 1.893 with Fc at 49.3 Hz and F3 at 33.4 Hz. The D2 is the better damped of the two; the D4 carries more lift near the corner.Pick the coil that suits your amplifier's stable load. The cabinet is direct fit for either.

Q: How do I wire this enclosure and set my impedance?

Both RS-W10 versions are dual voice coil. The D2 wires to 1 ohm with the coils in parallel or 4 ohms in series, and the D4 to 2 ohms parallel or 8 ohms series; Alpine's application guide covers every option. The one side mounted terminal cup carries that load to the amplifier. Target 500 to 600 watts RMS and confirm your amplifier is stable at the load you wire.

Q: Where is the terminal cup located on a down fire enclosure?

Side mounted. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup, and on a down fire cabinet that keeps the connection accessible with the enclosure in its installed position, since the baffle faces the floor. The cup is our Proline X ABS and carbon fiber composite unit, recessed, with stainless hardware, copper ring terminals and pre-wired 12 gauge OFC.

Q: How is this enclosure built?

V-groove and dado joinery, CNC cut on ShopSabre routers from Langboard Elite MDF, so every panel joint locks mechanically before adhesive is applied. The front baffle is a 1.5 inch double layer with the outer layer machined as a flush recess, and the driver lands on 8/32 threaded inserts with stainless machine screws. A windowed U-brace ties the long 41 inch panels together. Corners are square, the Down Fire series standard, which keeps the most internal volume for the footprint. Assembled and inspected in Tullahoma, Tennessee.

Q: Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining, and the quantity is chosen so it does not change the acoustic volume. Do not add more: packing a sealed box makes it behave as though it were larger, which walks the alignment away from the 0.539 cubic feet this cabinet was built to.

Q: Is the Alpine RS-W10 subwoofer included with this enclosure?

No. This listing is for the enclosure only. Bring your own RS-W10D2 or RS-W10D4; the driver is purchased separately. The cutout and mounting depth are direct fit, and the 1.75 inch feet ship uninstalled for an installed height of 6.5 inches.

SKU: PO 10-S DFW RSW

QUICK SPECS

Alignment: 0.539 cu ft net. D2 Qtc 1.457, Fc 46.0 Hz, F3 32.3 Hz; D4 Qtc 1.893, Fc 49.3 Hz, F3 33.4 Hz; height set by motor clearance
Down Fire Wide: 41"W x 12"D x 4.75"H in down fire position, 3" shallower and 11" longer than the standard 30 x 15, for under rear seats and narrow cargo floors
Driver: Alpine RS-W10D2 (DVC 2 ohm) or RS-W10D4 (DVC 4 ohm), 600W RMS / 1800W peak, 20mm Xmax, 0.04 cu ft displacement, neodymium motor
Build: Windowed U-brace, 1.5" double baffle, one side-mounted terminal cup, 12g OFC
Feet: 1.75", ship uninstalled. Installed height 6.5"

Shipping Included No freight charges at checkout. What you see is what you pay.

Built in Tennessee CNC cut from 3/4" Langboard Elite MDF. V-groove and dado joinery.

Advanced Terminal Cup Built in-house. ABS/Carbon Fiber. Stainless steel hardware. Copper ring terminals.

$ 299.99

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Performance Optimized Down Fire Wide Sealed 10" Shallow Sub Enclosure | Alpine RSW10

$ 299.99

More enclosures cut for Alpine subwoofers: Alpine Subwoofer Boxes

Enclosure Type Sealed

External Dimensions 41" W x 12" D x 4.75" H (measured in down fire position, excludes standoffs)

Gross Volume 0.58 cu ft

Net Volume 0.539 cu ft

Shipping Weight 38.7 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

Same height as our shortest Down Fire cabinet, 4.75 inches, but 12 inches deep instead of 15. If your under-seat space is shallow as well as low, this is the one.

Height here is set by the motor, not the airspace. The RS-W10 mounts in 3.25 inches and needs 0.75 inch above the magnet, so the cabinet cannot go lower, and at that height the wide footprint holds 0.539 cubic feet net, a little more than the 0.50 the standard box was built to. That nudges Qtc down to 1.457 on the D2 and 1.893 on the D4. More air is the safe direction.

Neodymium is why it works at all. Alpine publishes 0.04 cubic feet of displacement, so nearly the whole cavity is usable air. 600 watts RMS, 20mm of one-way excursion, 54mm peak-to-peak.

Dual voice coil in 2 or 4 ohm. Set your final impedance at the driver. Target 500 to 600 watts RMS.

Product Details

Proline X Performance Optimized Down Fire Wide 10" Sealed

Under rear seat and narrow cargo floor fitment. Cut for the Alpine RS-W10 Shallow

Down Fire WideV-Groove and Dado12" Shallow DepthLangboard Elite MDF

0.539cu ft net

1.457 / 1.893system Qtc, D2 / D4

32.3 HzF3 rolloff, D2

4.75 incabinet height, excludes feet

The Down Fire Wide Format

Down Fire Wide answers a specific space problem. The floor under the rear seat of a truck or SUV, and many narrow cargo floors, is long and shallow, and a standard 30 by 15 inch enclosure will not go in it.

So the cabinet is turned sideways. This one runs 41 inches wide by 12 inches deep by 4.75 inches tall, measured in the down fire position. Against our standard 30 by 15 inch RS-W10 cabinet it takes the same RS-W10 driver, sits 3 inches shallower front to back and runs 11 inches longer. The airspace lost from the depth is recovered along the length, so the driver still gets a properly sized chamber rather than a compromised one.

Which one to choose. If you have 15 inches of depth, the standard 30 by 15 cabinet is the pick: it is shorter end to end and easier to place. Choose this one when depth is the limiting dimension and you have 41 inches of run. Measure the depth first; under seat spaces vary widely between cab configurations.

Performance, Performance Optimized, and Micro

Proline X builds three tiers of Down Fire enclosure. The difference is not finish or materials, it is whether the cabinet was designed for a category or for a driver, and how much of the fitting work is already done for you.

	Performance	Performance Optimized	Micro Series
Fitment	Universal. Accepts any subwoofer that clears the published cutout and mounting depth.	Woofer specific. Cut for one named subwoofer, with cutout, mounting depth, magnet clearance and displacement drawn in CAD from that driver.	Woofer specific. Cut for one named subwoofer.
Footprint	Sized to the driver diameter. 24.5 by 13.5 inches on the 10 inch.	Shared 30 by 15 inch platform on most builds. Down Fire Wide variants like this one run long and shallow for under seat fitment.	Compact per driver footprint. 21.5 by 14.5 inches on the 10 inch.
Front baffle	Single, 3/4 inch.	Double layer, outer layer machined as a flush recess. 1.5 inch.	Double, 1.5 inch.
Driver mounting	Solid flange. You drill your own mounting holes.	8/32 threaded inserts, stainless machine screws included.	8/32 threaded inserts, stainless machine screws included.
Joinery	V-groove and dado, CNC cut.	V-groove and dado, CNC cut, perimeter cross brace.	Stack fab, dowel reinforced.
Published alignment	Modeled Qtc profiles across a range of drivers. No single response curve.	A real predicted Qtc and F3 for that exact driver, calculated from its own Thiele-Small parameters.	Target alignment described in the listing.
Carpet	Gray standard, black optional.	Plush black.	Plush black.
Warranty	1 year limited.	1 year limited.	2 years.

Feet ship with every tier, uninstalled on purpose. Mount them where your floor wants them for a down fire install, or leave them off and run the cabinet front firing or up firing. The orientation is yours to choose.

This page is a Performance Optimized enclosure. The cutout, the mounting depth and the chamber volume all come from the Alpine RS-W10's own numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.

Built Around the Alpine RS-W10

The baffle is bored to the RS-W10's 9-5/8 inch, 243mm cutout, and the frame is round and sits on the 12 inch deep baffle with material to spare. At 4.75 inches this is the same height as our standard 30 by 15 RS-W cabinet, the shortest in the Down Fire line, now 3 inches shallower front to back.

The driver ships as the RS-W10D2, dual 2 ohm, or the RS-W10D4, dual 4 ohm, rated 600 watts RMS and 1800 watts peak with 20mm of one way linear excursion and 54mm of peak to peak mechanical travel across 380 cm² of cone area. The motor is a high-grade neodymium design driving a 4 inch high-temperature voice coil, with Alpine's DD Linear dual magnetic gap for low distortion at high excursion, a vented coil former and motor cooling fins.

Neodymium is why the cabinet can be this short. There is no ferrite slug behind the cone eating internal air, and Alpine publishes only 0.04 cubic feet of displacement. Free air resonance is 30.0 Hz on the D2 and 31.0 Hz on the D4, and the efficiency bandwidth product sits well inside the range that calls for a sealed load.

Net Volume and Alignment

The chamber holds 0.539 cubic feet net, from 0.585 cubic feet gross after 0.04 cubic feet of driver displacement, published by Alpine.

Both coil variants are worth stating because the enclosure ships without drivers. The Dual 2-Ohm has a Qts of 0.950 against a 20.64 litre Vas; the Dual 4-Ohm has a Qts of 1.190 against a 23.35 litre Vas. Fs is 30.0 Hz on the Dual 2-Ohm and 31.0 Hz on the Dual 4-Ohm. In this chamber they land as follows.

Coil	System Qtc	Fc	F3, anechoic
RS-W10D2, dual 2 ohm	Qtc 1.457	46.0 Hz	32.3 Hz
RS-W10D4, dual 4 ohm	Qtc 1.893	49.3 Hz	33.4 Hz

Height here is set by the driver's mounting depth, not by the airspace. The 3.25 inch motor rises off the baffle into the cavity and needs 0.75 inch of clearance above it, and the cabinet cannot be built lower than that. At that height the 41 by 12 footprint holds 0.539 cubic feet net, more than the 0.50 cubic feet the standard 30 by 15 box was built to. The extra air lowers Qtc and eases the rolloff, which is the safe direction for a sealed alignment. It is a consequence of motor clearance, not a design target.

These are high Q alignments with real lift near the corner frequency. That is the RS-W10's character in a small sealed box: it is voiced for output from very little air.

True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver displacement, not estimated from external dimensions minus wall thickness. All figures are anechoic; firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz and in-car response extends well below them.

Down Fire Wide Construction

Cut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3/4 inch MDF, a dense 48.5 lb/ft³ board with a 200 psi internal bond and 410,000 psi MOE. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps the cabinet airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.

The cabinet measures 41 inches wide by 12 inches deep by 4.75 inches tall, measured in the down fire position. The 1.75 inch feet ship with the enclosure but are not installed, so plan the space around an installed height of 6.5 inches if you use them.

1.5 Inch Double Baffle

Two 3/4 inch layers laminated to 1.5 inches, with the outer layer machined as a flush recess so the driver bolts to the inner layer on 8/32 threaded inserts. Stainless machine screws included.

Windowed U-Brace

A windowed U-brace dadoed to the shell ties the long 41 inch panels together without closing off the chamber. Polyfill is installed as a light wall lining.

Side-Mounted Terminal Cup

One Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, side mounted and pre-wired in 12 gauge OFC, so it stays accessible with the baffle facing the floor.

Power and Wiring

Alpine rates the RS-W10 at 600 watts RMS and 1800 watts peak. Target 500 to 600 watts RMS on the amplifier. A subsonic filter around 25 Hz is cheap insurance on a driver with this much travel.

Both versions are dual voice coil, so you set your final impedance at the driver, and Alpine's application guide covers every wiring option for each. One side mounted terminal cup, pre-wired in 12 gauge OFC.

Bring your own RS-W10D2 or RS-W10D4; the driver is purchased separately. The enclosure carries a 1 year limited warranty. Plush black carpet.

Cut for the Driver, Not the Catalog

Down Fire Wide, built for the space under a rear bench, one at a time in Tullahoma, Tennessee. Questions on fitment or amplifier matching, call 931-563-5151.

Specifications

Series	Proline X Performance Optimized Down Fire Wide
Compatible Driver	Alpine RS-W10D2 (DVC 2 ohm) or RS-W10D4 (DVC 4 ohm). Direct fit
Enclosure Type	Sealed, single driver, down fire, floor coupled
Intended Fitment	Under the rear seat of trucks and SUVs and narrow cargo floors, where depth is the limiting dimension
Firing Direction	Down firing, driver fires toward the floor. Feet ship uninstalled, so front or up firing is also possible
Chamber Configuration	Single sealed chamber, windowed U-brace, one side-mounted terminal cup
External Width	41 in
External Depth	12 in
External Height	4.75 in in the down fire position, excludes feet
Installed Height	6.5 in with the 1.75 in feet
Standard 30 x 15 Equivalent	30 x 15 x 4.75 in, 0.50 cu ft net. Same driver, deeper and shorter footprint
Internal Volume, Gross	0.585 cu ft
Net Volume	0.539 cu ft after displacement
Height Set By	Driver clearance: the 3.25 in motor, 0.75 in minimum above it
Clearance Above Motor	0.75 in
Alignment, D2	Qtc 1.457, Fc 46.0 Hz, F3 32.3 Hz anechoic
Alignment, D4	Qtc 1.893, Fc 49.3 Hz, F3 33.4 Hz anechoic
Woofer Opening	9-5/8 in / 243mm, Alpine spec
Mounting Depth	3.25 in
Driver Fs	30.00 Hz (D2) / 31.00 Hz (D4)
Driver Qts	0.950 (D2) / 1.190 (D4)
Driver Vas	20.64 L (D2) / 23.35 L (D4)
Driver Cone Area (Sd)	380 cm2
Driver Xmax (One-Way)	20mm
Driver Xmech (Peak-to-Peak)	54mm
Driver Voice Coil	4 in, high-temp
Driver Motor	High-grade neodymium, DD Linear dual magnetic gap
Driver Power Handling	600 W RMS / 1800 W peak
Recommended Power	500 to 600 W RMS
Voice Coil Configuration	Dual voice coil, final impedance set at the driver
Driver Displacement	0.04 cu ft, published by Alpine
Material	Langboard Elite MDF
Construction	CNC cut on ShopSabre routers, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in double baffle, outer layer machined as a flush recess
Internal Bracing	Windowed U-brace, dadoed to the shell
Corner Profile	Square, Down Fire series standard
Driver Mounting	8/32 threaded inserts, stainless machine screws included
Terminal Cup	One Proline X ABS and carbon fiber composite, side mounted
Internal Wiring	12 gauge OFC
Feet	Included, 1.75 in, shipped uninstalled
Damping	Polyfill pre-installed as a light wall lining
Carpet	Plush Black
Bundle Options	Enclosure only, bring your own RS-W10D2 or RS-W10D4
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

0.539

cu ft per chamber

System Qtc

1.46–1.89

sealed

Half power

32.3–33.4

Hz · F3

Xmax at

950

W RMS · no filter

With 25 Hz subsonic

957

W RMS · +1%

Amplifier

500–600

W RMS recommended

This enclosure holds 0.539 cu ft net per chamber. In it the Alpine RS-W10D2 runs a system Qtc of 1.46–1.89 with half power at 32.3–33.4 Hz, and the cone reaches its 20.0 mm travel limit at 950 W, above the driver’s 600 W thermal rating, so heat stops you before travel does. A 25 Hz subsonic filter adds little here: 957 W against 950 W, 1 percent. The box already resonates at 46–49 Hz, so its own rolloff has removed most of what the filter would have stopped.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 18.7–27.0

D2 · EBP 27.0D4 · EBP 18.7

EBP under 50 means a motor that wants a sealed load. The RS-W10D2 sits at 18.7–27.0, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

0.539 cu ft against a 20.6 L Vas.

α = Vas ÷ Vb = 1.35 · Fc = Fs√(α+1) = 46–49 Hz · Qtc = 1.46–1.89

D2 · Qtc 1.46, Fc 46 Hz, F3 32.3 HzD4 · Qtc 1.89, Fc 49 Hz, F3 33.4 Hz

The box lifts resonance from 30.0–31.0 Hz free-air to 46–49 Hz and half power lands at 32.3–33.4 Hz, anechoic, before any cabin gain. This enclosure ships without a driver, so both coil variants the maker offers are plotted. They do not load the same box the same way.

03The watts that reach Xmax (in this enclosure)

Travel scales with the square root of power, so there is one wattage that puts the cone exactly on 20.0 mm, and in this alignment a subsonic filter barely moves it.

P_Xmax = 950–962 W unfiltered → 957–982 W with a 25 Hz subsonic

D2 · 962 W, no filterD4 · 950 W, no filterD2 · 982 W with subsonic at 25 Hz, 24 dB/octD4 · 957 W with subsonic at 25 Hz, 24 dB/octXmax 20.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 20.0 mm. Unfiltered that is 950 W, reached first at 45 Hz. It sits above the 600 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct, and they sit almost on top of the solid ones: 957 W against 950 W. At 46–49 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.

Param	Value	Unit	Note
Fs	30.00 / 31.00	Hz	free-air resonance
Qts	0.950 / 1.190		D2 / D4
Vas	20.64 / 23.35	L	equivalent compliance
Sd	380.0	cm²	effective piston area
Xmax	20	mm	one-way linear travel
Pe	600	W	continuous RMS
SPL	78.9	dB	1 W / 1 m, derived from T/S

Driver parameters as published by Alpine R-Series Shallow application guide. Curves computed against this enclosure’s actual net airspace.

Materials

Material

Built From a Spec Sheet, Not a Sales Sheet

Every Proline X Performance Series enclosure is CNC-cut from Langboard Elite MDF, 3/4" (18mm) panels produced to published mill specifications. Most enclosure manufacturers source generic MDF without published data. We can tell you the internal bond rating, the modulus of elasticity, the modulus of rupture, and the face and edge screw holding strength for every panel in this enclosure, because we chose the material based on those numbers, not on price or availability.

Langboard Elite is produced in the United States. The specifications below are pulled directly from Langboard's published mill data and are verifiable. This is the same panel stock used in our full Proline X lineup.

Specifications

Langboard Elite MDF: Published Mill Data

Property	Value	Why It Matters
Panel Stock	Langboard Elite MDF	Named, verifiable panel source, not generic "high-density MDF"
Thickness	3/4" (18mm)	Industry standard for subwoofer enclosures; panels below this flex under pressure
Density	48.5 lbs/ft³	Higher density = less porosity, better screw retention, reduced resonance
Internal Bond	200 psi	Measures resistance to delamination under sustained internal pressure. The most enclosure-relevant spec on this sheet
Modulus of Rupture (MOR)	4,200 psi	Bending strength before the panel breaks, relevant for larger unsupported baffle spans
Modulus of Elasticity (MOE)	410,000 psi	Stiffness under load; higher MOE means less panel flex under bass pressure, less resonance
Face Screw Holding	325 lbs	How firmly the panel surface holds a screw; critical for baffle joint integrity over time
Edge Screw Holding	250 lbs	Panel edge retention, relevant for every joint that isn't face-to-face

Internal Bond

200 psi: The Number That Actually Matters for Enclosures

The internal bond rating measures how well the MDF panel resists delamination under sustained pressure applied perpendicular to the face. In a subwoofer enclosure, every bass transient generates a pressure pulse that pushes outward on every panel simultaneously. A panel that begins to delaminate internally loses stiffness gradually. The symptoms are slow: a box that starts to sound softer, less defined, less punchy over months of use. 200 psi internal bond is the spec that determines how long this enclosure holds its acoustic integrity under daily use at real power levels.

Stiffness

410,000 psi MOE: Less Flex, Less Resonance

The modulus of elasticity measures panel stiffness, its resistance to bending under load. A stiffer panel flexes less under the pressure generated by a high-excursion driver at volume. Panel flex is a source of acoustic coloration: the panel itself begins to radiate sound at its own resonant frequency, adding distortion to the output. 410,000 psi stiffness combined with V-groove and dado joinery means the panels stay rigid and the bracing controls resonance at the structure level, not the panel level. The bass you hear comes from the driver, not the box.

Screw Holding

325 lb Face / 250 lb Edge: Joints That Stay Locked

Screw holding strength determines how firmly the panel grips a fastener at the face and at the edge. This matters most at the baffle joint, where the front panel meets the side panels and where the driver is mounted. A panel with low screw holding strength allows fasteners to loosen over time under vibration, leading to air gaps at the joint and loss of acoustic seal. 325 lb face screw holding strength means the baffle hardware stays put. Combined with dado joinery and adhesive, the front panel on a Proline X Performance Series enclosure is not going anywhere.

Sourcing

Named Panel Stock: Not "Premium MDF"

The phrase "premium MDF" or "high-density MDF" appears on marketing copy for enclosures across every price point, from $40 to $400. It is not a specification. It is a description with no defined standard. Langboard Elite is a named, sourced, mill-documented product with published data. We name it in our copy because naming it holds us accountable to the spec. You can look up Langboard Elite independently, verify the numbers on this page, and confirm you are getting what we say you are getting. That is the point.

Why Proline X?

Most enclosures are built to a price point. Proline X is built to a spec. Every box starts with published-data MDF, gets CNC-cut to exact internal volume, and is assembled by hand in our Tennessee facility. The difference shows up in the measurements, and in how the box holds up two years into daily use.

CNC-Cut to Spec

Panels are machine-cut on ShopSabre CNC routers and joined with V-groove and dado joinery. Consistent geometry, no hand-cut variance, no gaps at the joints.