Proline X PO 18-S W AA3 sealed wedge, front baffle with gloss black insert and pre-wired leads, 23.6 by 21 inches.

Proline X

Performance Optimized Wedge Sealed 18" Enclosure | Ampere Audio AA-3.0 18

Q: Does this fit the Ampere Audio AA-3.0 18, and will any other 18 inch fit?

The AA-3.0 18, yes, in both coil versions. The baffle is cut to 16.88 in, Ampere's published cutout, under the 18.50 in frame. The 12.50 inch motor clears the cabinet with 0.75 inch to spare.Any other 18, no. The airspace is engineered around the AA-3.0 18's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

Q: What amplifier power should I run, and how should I wire it?

Ampere rates the AA-3.0 18 at 2000 watts RMS, so target 1400 to 2000 watts RMS at the final load.Ampere sells the AA-3.0 18 as dual 1 ohm and dual 2 ohm: the dual 1 ohm is two 1 ohm coils, 2 ohms in series or 0.5 ohm in parallel; the dual 2 ohm is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm your amplifier's minimum stable impedance first.

Q: Why the wedge angle, and why rear-firing into the trunk?

The seat-side face carries a 20 degree rake that matches the lean of a factory rear seat back, so the cabinet sits flush against it and the cargo space in front stays usable. The baffle is the vertical trunk-lid-side face, so the driver fires rearward into the trunk cavity.The trunk acts as an acoustic extension for the sealed box, and the cabin adds real output below 50 Hz, so in-vehicle response runs deeper than the anechoic 38.8 Hz on the dual 1 ohm and 35.4 Hz on the dual 2 ohm on this page.

Q: Why is the front baffle double-layered?

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A single 3/4 inch panel flexes under the pressure an 18 inch woofer puts on it at 2000 watts, which smears output and works the driver loose over time; the second layer stiffens the face and gives the mounting hardware twice the material to bite.The outer layer is machined as a flush recess to Ampere's 18.50 inch frame, so the driver bolts to the inner layer and sits flush with the gloss black acrylic insert.

Q: What is the expected low-frequency extension?

Anechoic F3 is 38.8 Hz on the dual 1 ohm and 35.4 Hz on the dual 2 ohm. The lower-Q coil rolls off gently with F3 above fc; the higher-Q coil carries a small lift near resonance.Those figures exclude cabin gain. In a car the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

Q: Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume.Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 2.96 cubic feet this cabinet was built to.

Q: Is the driver included, and are the threaded inserts installed?

No driver. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, one side-mounted pre-wired terminal cup, the polyfill lining already in place, and a threaded insert kit with stainless machine screws.The inserts ship loose on purpose: Ampere prints no bolt circle for the AA-3.0 18, so you set the driver in the recess, mark its holes, drill and press the inserts. The Ampere Audio AA-3.0 18 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 18 inch box.

SKU: PO 18-S W AA3 BB

QUICK SPECS

Best For: Ampere Audio AA-3.0 18 Trunk-Fit Builds
Net Volume: 2.96 cu ft (3.24 cu ft Gross)
Driver Match: Ampere Audio AA-3.0 18 (dual 1 ohm and dual 2 ohm)
Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Insert Kit

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.

$ 449.99

Acrylic Insert Color

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Performance Optimized Wedge Sealed 18" Enclosure | Ampere Audio AA-3.0 18

Enclosure Type Sealed

External Dimensions 23.57" W x 21" H x 20.43" D at base tapering to 12.79" D at top

Gross Volume 3.24 cu ft

Net Volume 2.96 cu ft

Shipping Weight 56 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

2.96 cubic feet: Qtc 0.679 on the dual 1 ohm and Qtc 0.735 on the dual 2 ohm, F3 38.8 Hz on the dual 1 ohm and 35.4 Hz on the dual 2 ohm.

The 12.50 inch motor clears the raked back with 0.75 to spare; the airspace sets the rest of the cabinet.

Ampere's table needed reading carefully: no cone area is printed, so it is derived from their own Vas, Fs and moving mass. Displacement is estimated.

Inserts ship in the kit, not pressed: Ampere prints no bolt circle. Mark from the driver, drill, press. Sealed, so leave the polyfill as it is and run it at 2000 watts or under per driver.

Product Details

Performance Optimized Wedge | Ampere Audio AA-3.0 18

18" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design

2.96 ft3 Net3.24 ft3 GrossQtc 0.68 to 0.73Single Chamber Wedge23.57" x 21" x 12.79/20.43"Built in Tennessee

The Ampere Audio AA-3.0 18 in a Sealed Wedge

The AA-3.0 18 is Ampere's 18 inch in the AA-3.0 series: a cast aluminum basket, a carbon fiber reinforced cone, a 3 inch flat-wound four-layer voice coil with a 65 mm winding and a four-stack ferrite motor, rated 2000 watts RMS with 29 mm of one-way excursion, 12.50 inches of mounting depth on an 18.50 inch frame. Every Thiele-Small figure comes from Ampere's own published table for the AA-3.0 18, and the table holds together: the moving mass and resonance reproduce the published Vas on a cone area in class for an 18 inch driver. Ampere prints no cone area for this driver, so the 1136 square centimeters used for excursion and output figures is derived from Ampere's own Vas, resonance and moving mass.

2.96 cubic feet net on Ampere's published figures: the dual 1 ohm reads Qtc 0.679 with resonance at 37.2 Hz and half power at 38.8 Hz, and the dual 2 ohm reads Qtc 0.735 with resonance at 36.7 Hz and half power at 35.4 Hz. One cabinet serves both coils, built to the volume that keeps both closest to maximally flat. That is spread either side of maximally flat: the lower-Q coil a little drier, the higher-Q coil a little punchier.

Trunk-Load Wedge Design Explained

The driver mounts on the vertical trunk-lid-side face and fires rearward into the trunk cavity.

Seat-Side Face Matches Seat Lean

Angled face matches the roughly 20 degree factory seat lean.

Trunk-Lid-Side Face Fires the Woofer

Vertical baffle, cone firing rearward into the trunk cavity.

Trunk Cavity Loading

The trunk acts as an acoustic extension for a smoother presentation.

Preserves Trunk Cargo Space

The wedge tucks against the seat back and the space in front stays usable.

Engineered for the Ampere Audio AA-3.0 18

Anechoic half power lands at 38.8 Hz on the dual 1 ohm and 35.4 Hz on the dual 2 ohm, before any cabin gain. Ampere does not publish driver displacement, so an estimated 0.259 cubic feet per driver is taken out of the net figure.

Alignment Numbers

Driver	System Qtc	fc	F3
AA-3.0 18 dual 1 ohm	Qtc 0.679	37.2 Hz	38.8 Hz
AA-3.0 18 dual 2 ohm	Qtc 0.735	36.7 Hz	35.4 Hz

Mounting Geometry

The baffle is cut to 16.88 in, Ampere's published cutout, under the 18.50 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 12.79 in at the top to 20.43 in at the base, and the 12.50 in motor clears it with 0.75 in to spare. Ampere prints no bolt circle for the AA-3.0 18, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in the recess, mark its holes, drill, press the inserts and bolt it down.

What the Numbers Rest On

Langboard Elite MDF

Premium 3/4 in MDF throughout.

V-Groove and Dado Joinery

CNC cut V-grooves at every panel intersection, sides and brace seated in dados.

Double-Layer 1.5" Front Baffle

Two bonded 3/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.

Ampere's Published Parameters

dual 1 ohm: Fs 25.2 Hz, Qts 0.46, Qes 0.51, Qms 4.56, Vas 98.9 L, Mms 738.4 g, Bl 19.7 N/A, Re 1.7 ohm. dual 2 ohm: Fs 25 Hz, Qts 0.5, Qes 0.58, Qms 3.87, Vas 97.3 L, Mms 760.8 g, Bl 27.3 N/A, Re 3.6 ohm. Cone area 1136 cm2 (derived). Xmax 29 mm.

Wiring the Ampere Audio AA-3.0 18 to Your Amplifier

Ampere sells the AA-3.0 18 as dual 1 ohm and dual 2 ohm: the dual 1 ohm is two 1 ohm coils, 2 ohms in series or 0.5 ohm in parallel; the dual 2 ohm is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm the final load against your amplifier's minimum stable impedance before powering the system.

Power handling is 2000 watts RMS per driver. Aim for roughly 1400 to 2000 watts at the impedance you wire.

Built in Tennessee, Backed by Audio Intensity

Cut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one pre-wired terminal cup, 12 gauge OFC to the driver position. Polyfill wall lining installed. Threaded insert kit and stainless machine screws in the box. 1 year limited warranty. Enclosure only, the driver is purchased separately. Call or text 931-563-5151.

Ampere Audio AA-3.0 18: Cut for One Driver

2.96 cubic feet net at Qtc 0.68 to 0.73, F3 38.8 Hz on the dual 1 ohm and 35.4 Hz on the dual 2 ohm, cut direct fit and built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	Ampere Audio AA-3.0 18 (dual 1 ohm and dual 2 ohm), quantity 1. Direct fit
Configuration	Single 18 inch, single chamber sealed wedge
Mounting Position	Trunk or cargo area, tall face against the rear seat back
Firing Direction	Rearward into the trunk. Not a down fire design, no feet included
External Width	23.57 in
External Height	21 in at the seat face
External Depth	20.43 in at the base, tapering to 12.79 in at the top
Internal Volume, Gross	3.24 cu ft
Internal Volume, Net Acoustic	2.96 cu ft after the brace and the driver displacement
Driver Mounting Depth	12.50 in required; 0.75 in clearance above the motor against the raked rear panel
Alignment, dual 1 ohm	Qtc 0.679, fc 37.2 Hz, F3 38.8 Hz anechoic
Alignment, dual 2 ohm	Qtc 0.735, fc 36.7 Hz, F3 35.4 Hz anechoic
Woofer Opening	16.88 in, Ampere's published cutout
Frame Outer Diameter	18.50 in
Bolt Circle	Not printed by Ampere; threaded insert kit included
Driver Displacement	0.259 cu ft, estimated; Ampere publishes none
dual 1 ohm Fs / Qts / Qes / Qms / Vas	25.2 Hz / 0.46 / 0.51 / 4.56 / 98.9 L
dual 2 ohm Fs / Qts / Qes / Qms / Vas	25 Hz / 0.5 / 0.58 / 3.87 / 97.3 L
Driver Sd	1136 cm2, derived from Ampere's Vas, Fs and moving mass
Xmax	29 mm one way, Ampere spec
Driver Power Handling	2000 W RMS
Wiring Options	Ampere sells the AA-3.0 18 as dual 1 ohm and dual 2 ohm: the dual 1 ohm is two 1 ohm coils, 2 ohms in series or 0.5 ohm in parallel; the dual 2 ohm is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it.
Parameter Source	Ampere Audio published T/S and dimension tables, AA-3.0 series page
Material	Langboard Elite MDF
Construction	CNC cut, 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 brace, dadoed to the shell
Driver Mounting	Threaded insert kit included, NOT pre-installed: Ampere prints no bolt circle
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
Acrylic Insert	Gloss black acrylic baffle insert standard; None variant minus $20
Damping	Light polyfill wall lining, does not alter acoustic volume
Carpet	Plush black
Shipping Weight	56 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

2.96

cu ft

System Qtc

0.68–0.73

sealed

Half power

35.4–38.8

Hz · F3

Xmax at

3403

W RMS · no filter

With 25 Hz subsonic

5576

W RMS · +64%

Amplifier

2000

W RMS recommended

This enclosure holds 2.96 cu ft net . In it the Ampere Audio AA-3.0 18 runs a system Qtc of 0.68–0.73 with half power at 35.4–38.8 Hz, and the cone reaches its 29.0 mm travel limit at 3403 W, above the driver’s 2000 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 5576 W — +2174 W, or 64 percent more power for the same 29.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 43.1–49.4

D1 · EBP 49.4D2 · EBP 43.1

EBP under 50 means a motor that wants a sealed load. The AA-3.0 18 sits at 43.1–49.4, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

2.96 cu ft against a 98.9 L Vas.

α = Vas ÷ Vb = 1.18 · Fc = Fs√(α+1) = 37 Hz · Qtc = 0.68–0.73

D1 · Qtc 0.68, Fc 37 Hz, F3 38.8 HzD2 · Qtc 0.73, Fc 37 Hz, F3 35.4 Hz

The box lifts resonance from 25.0–25.2 Hz free-air to 37 Hz and half power lands at 35.4–38.8 Hz, anechoic, before any cabin gain. Ampere prints no cone area for this driver; it is derived from Ampere’s own Vas, Fs and moving mass. Driver displacement is not published and is estimated.

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 29.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

P_Xmax = 3403–3526 W unfiltered → 5576–5661 W with a 25 Hz subsonic

D1 · 3403 W, no filterD2 · 3526 W, no filterD1 · 5661 W with subsonic at 25 Hz, 24 dB/octD2 · 5576 W with subsonic at 25 Hz, 24 dB/octXmax 29.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 29.0 mm. Unfiltered that is 3403 W, reached first at 20 Hz. It sits above the 2000 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: stopping the cone wasting travel below the passband lets it take 5576 W before hitting the same 29.0 mm. That is 64 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	25.20 / 25.00	Hz	free-air resonance
Qts	0.460 / 0.500		D1 / D2
Vas	98.90 / 97.30	L	equivalent compliance
Sd	1135.5 / 1134.1	cm²	effective piston area
Xmax	29	mm	one-way, as Ampere publish it
Pe	2000	W	continuous RMS
SPL	86.8	dB	1 W / 1 m, derived from T/S

Driver parameters as published by Ampere Audio published T/S table. Curves computed against this enclosure’s actual net airspace.

Customer Installs

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.