Proline X

Professional Series Ported 8" Enclosure | American Bass VFL Comp 8

Q: Do I need a subsonic filter?

Yes, at 26 Hz, 24 dB per octave. Below tuning a vented box stops loading the cone and excursion runs away toward DC. With the filter in place this cabinet puts the American Bass VFL Comp 8 at 78 percent of its usable travel at 720 W.

Q: Would a sealed box be better for me?

Not one we can show you. We do not build a sealed enclosure for the American Bass VFL Comp 8 and American Bass publish no sealed volume for it, so the Performance Graphs tab carries no ported-versus-sealed chart: the only sealed box left to plot would be this cabinet stuffed and sealed, which nobody would build, and a comparison against it would tell you nothing you could buy. What a vented box gives up is the region below tuning, where the cone unloads and the 26 Hz subsonic filter takes over; around 33.0 Hz the vent carries the load and cone travel drops to its minimum, which no sealed alignment can do.

Q: How does the front port work?

It is a vertical slot beside the woofer, the full height of the cavity, 1.75 inches wide and 21.9 square inches. It runs 7.00 inches to the back wall and turns once along it for 19.46 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 21.3 metres per second at 720 W, 53 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 12.6 metres per second against the 17 metres per second threshold where a slot starts to chuff.

Q: What does the price cover, and how does it ship?

50 lb, 30.00" W x 14.00" H x 12.50" D external. Every Professional cabinet is priced the same way, by its size: this one is 3.04 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 50 lb parcel and checkout adds nothing. Do not add polyfill; it ships dry on purpose.

Q: Is the VFL Comp 8 included?

No. This is an enclosure only, cut for the American Bass VFL Comp 8 specifically: the 7.400 inch cutout, the 5.430 inch mounting depth allowance and the 1.35 cubic foot alignment all come from American Bass's published parameters. It fits both coil versions (D2 and D4), and the cabinet was checked against both. Bring your own driver.

SKU: Pro 8-P VFLC8

QUICK SPECS

Alignment: 1.35 cu ft net vented at 33.0 Hz. F3 28.0 Hz anechoic, 5.69 dB passband ripple
Driver: American Bass VFL Comp 8 D2/D4, 600 W RMS, 13.0 mm Xmax, 37.20 Hz Fs
Build: Front-firing standard box, 2.25" three-layer baffle with the woofer flush-mounted in the outer layer, American Bass logo acrylic, dado joinery, 21.9 sq in front slot port beside the woofer with one bend along the back wall, port and excursion gated at 720 W
Cabinet: 30.00" W x 14.00" H x 12.50" D, 50 lb, threaded insert kit included

Shipping Included No freight charges at checkout on US orders. International orders are quoted live carrier rates at checkout.

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.

$ 411.99

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Complete Your System

Arc Audio X2 1100.1 Monoblock Subwoofer Amplifier 1100W Class D - Arc Audio Amplifier for car audio systems

Arc Audio Arc Audio X2 1100.1 Monoblock Subwoofer Amplifier | 1100W | Class D $ 758.00

Professional Series Ported 8" Enclosure | American Bass VFL Comp 8

$ 411.99

Enclosure Type Ported

External Dimensions 30.00" W x 14.00" H x 12.50" D

Gross Volume 1.96 cu ft

Net Volume 1.35 cu ft

Tuning Frequency 33.0 Hz

Port Area 21.9 Square Inches

Shipping Weight 56 lbs

INSTALLER'S TAKE

I built this box for one VFL Comp 8 on the full Professional chassis: three layers of baffle with the frame flush in the outer one, and a slot port that runs along the back wall to put 33.0 Hz in a 12.5 inch deep box.

One cabinet serves both coils. It was solved so the VFL Comp 8 D2 and the D4 each pass every velocity, excursion and ripple gate in the same box.

American Bass publishes no bolt circle, so the box ships with a threaded insert kit rather than pressed inserts.

600 watts RMS by American Bass's rating. The D2 wires to 4 ohms with its coils in series or 1 ohm in parallel; the D4 wires to 8 ohms with its coils in series or 2 ohms in parallel. American Bass publishes no mounting hole locations for the VFL Comp 8, so the inserts are not in the baffle when the box arrives. The insert kit is in the box: set the inserts where the woofer's own holes fall, with the drill bit and the 2.5 inch allen-head screws in the kit, and lay the gasket tape before the woofer goes down.

The Performance Optimized wedge is the smaller and cheaper box, and I try it first for every driver. I could not make its port keep up with the VFL Comp 8: the calmest port that fits that envelope goes noisy at about 576 watts, under what this coil is rated to take, so I did not sell you that box.

It ships dry. Do not add polyfill to a ported box. Set your subsonic filter at 26 Hz.

Product Details

Proline X Professional 8" Ported

One VFL Comp 8 in a front-firing box, vented at 33.0 Hz on a three-layer flush-mount baffle

1.35 cu ft net Tuned 33.0 Hz F3 28.0 Hz 2.25" three-layer baffle Cut for the VFL Comp 8 Built in Tennessee

1.35cu ft net

33.0Hz tuning

28.0Hz F3 anechoic

21.9sq in port area

Why this driver is vented at 33.0 Hz

The VFL Comp 8 is American Bass's 8 inch at 37.2 Hz, a Qts of 0.35, 5.0 litres of Vas and 600 W RMS. This cabinet gives it 1.35 cubic feet net behind a 2.25 inch three-layer baffle, vented at 33.0 Hz through a 21.9 square inch slot beside the woofer, for an anechoic F3 of 28.0 Hz in a 30 by 14 by 12.5 inch front-firing box.

Threaded insert kit ships with this box. American Bass does not publish the mounting hole locations for the VFL Comp 8, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.

Sealed, the VFL Comp 8 needs 0.06 cubic feet net to reach a Qtc of 0.707. Vented, it trades that for deeper extension. The slot is gated at 720 W, 1.2 times American Bass's rating: the channel runs 21.3 m/s and the mouth 12.6, and the cone peaks at 10.1 of its 13 mm with the subsonic filter in place.

What makes it Professional

Three-layer baffle, flush mount

Three layers of 3/4 inch Langboard Elite make a 2.25 inch front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it carry the mounting hardware and the load.

American Bass logo acrylic

A glossy black acrylic insert with the American Bass mark sits in the outer layer beside the woofer. It is standard on every Professional cabinet.

Threaded insert kit ships with this box

Threaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.

Port gated at 720 W

The 21.9 square inch slot beside the woofer is sized so the channel runs 21.3 metres per second and the mouth 12.6 metres per second at 1.2 times the driver's rating, under the 17 metres per second where a slot starts to chuff. The channel runs 7.00 inches along its wall and turns once along the back wall for another 19.46 inches, which is why a 33.0 Hz tuning fits a 12.50 inch deep box.

Why this is a Professional build

Every driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The VFL Comp 8 did not clear the port gate there. The calmest wedge port that fits that envelope is 13.0 square inches at 29.0 by 9.62 by 13.90 inches, and its mouth runs 17.3 metres per second at 600 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 576 W. The slot on this box reaches 21.9 square inches and holds the mouth at 12.6 metres per second at 720 W.

What the price covers

Every Professional cabinet is priced the same way, by its size: this one is 3.04 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 50 lb parcel and checkout adds nothing.

The cabinet

30.00" W x 14.00" H x 12.50" D external. Two windowed braces run front to back either side of the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. Inside the 30 by 14 Professional envelope for a single 8, 12.5 inches deep. 8.71 inch frame, flush in the outer baffle layer, 7.40 inch cutout, 5.43 inches of mounting depth. It ships as a parcel.

American Bass publishes Fs, Qts, Vas, cone area and Xmax for the VFL Comp 8 on its product page, but no overall frame diameter, no driver displacement and no Cms. The frame is taken as 8.71 inches, the larger of the nominal size plus half an inch and the 7.40 inch cutout plus a typical flange, so the baffle is never cut short; the 0.055 cubic feet of displacement is our estimate from comparable 8 inch woofers and moves the tuning by a fraction of a hertz. American Bass does not say whether its 13 mm Xmax is one-way or peak to peak; we read it as one-way and keep power at its own rating. Tuning includes a 1.5 Hz fold loss that is an estimate, not a bench measurement. American Bass does not publish the mounting hole locations for the VFL Comp 8, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.

The numbers to respect

Set a 26 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in place the cone reaches 10.1 mm of its 13.0 mm at 720 W.

Enclosure Specifications

Series	Proline X Professional
Driver-Specific Fitment	American Bass VFL Comp 8 D2/D4 (Dual 2 Ohm or Dual 4 Ohm)
Enclosure Type	Ported \| Front-Firing Standard Box
External Width	30.00 Inches
External Height	14.00 Inches
External Depth	12.50 Inches
Internal Volume (Gross)	1.96 Cubic Feet
Internal Volume (Net After Displacement)	1.35 Cubic Feet
Port Type	Vertical Slot Beside The Woofer \| Front Exit \| One 90 Degree Bend Along The Back Wall
Port Geometry	1.75 x 12.50 Inches, 21.9 Square Inches, 31.96 Inches Of Path
Port Area	21.9 Square Inches
Port Tuning (Fb)	33.0 Hz
Port Mouth	1/2 In Roundover On All Four Edges, 37.1 Square Inches At The Face
Port Air Velocity	21.3 m/s In The Channel, 12.6 m/s At The Mouth, At 720 W (17.0 m/s Chuff Threshold)
Design Power Basis	720 W RMS (1.2 x The Driver Rating) For Port Velocity And Excursion
Predicted F3	28.0 Hz (Anechoic)
Passband Ripple	5.69 dB (Anechoic)
Subsonic Filter	26 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs	37.20 Hz
Driver Qts	0.350
Driver Qes / Qms	0.377 / 4.140
Driver Vas	5.009 Liters / 0.177 Cubic Feet
Driver Sd	188.7 Square Centimeters
Driver Mms	166.26 g
Driver BL	9.90
Driver Xmax	13mm (One-Way)
Driver Displacement	0.06 Cubic Feet (Published by American Bass)
Driver Sensitivity	80.9 dB
Driver Power Handling	600 Watts RMS
Driver Overall Diameter	8.713 Inches (American Bass Spec)
Mounting Depth Required	5.430 Inches (American Bass Spec)
Cutout Diameter	7.400 Inches (American Bass Spec)
Flush Mount Recess	9.625 Inches In The Outer Layer
Material	Langboard Elite 3/4" MDF
Construction	ShopSabre CNC / Two Windowed Braces Front To Back Either Side Of The Woofer
Joinery	Dado Joinery (CNC-Cut), Flat Panels
Front Baffle Construction	Three 3/4" MDF layers, 2.25" total \| Woofer Flush-Mounted In The Outer Layer
Baffle Layers	3
Acrylic	Glossy Black American Bass Logo Insert, Outer Layer, Standard
Mounting Hardware	Threaded Insert Kit Included: 8-12 Inserts, Drill Bit, 2.5 In Allen-Head Screws, Allen Key, Gasket Tape
Voice Coil Configuration	Dual 2 Ohm
Terminal Cup	Proline X ABS/Carbon Fiber Composite \| Back Panel, Terminal-Cup Side \| 12g OFC Pre-Wired
Damping	None - Ships Dry. Polyfill Detunes A Ported Enclosure
Recommended Power	420-600 Watts RMS (American Bass Rated: 600W RMS)
Carpet Finish	Plush Black
Shipping Weight	56 lb
Shipping	UPS Ground Parcel, Included In The 48 States
Bundle Options	Enclosure Only (Bring Your Own American Bass VFL Comp 8)
Warranty	2-Year Limited (Enclosure)
Manufactured	Tullahoma, Tennessee, USA

Performance Graphs

Net airspace

1.35

cu ft

Tuning

33.0

Hz · Fb

Half power

28.0

Hz · F3, anechoic

Xmax at

1184

W RMS · 26 Hz subsonic

With NO filter

411

W RMS · unfiltered

Port

12.6

m/s at the mouth · 720 W

01Is this driver right for a ported box?

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

EBP = Fs ÷ Qes = 98.7

American Bass VFL Comp 8 D2 · EBP 98.7

Between 50 and 100 a driver takes either load, and the choice becomes one of priorities rather than of physics. The American Bass VFL Comp 8 D2 reads 98.7. Ported buys output and low-end reach around tuning; sealed buys a shallower rolloff below it. This cabinet takes the first trade.

02What the box does to it

1.35 cu ft net against a 5.0 L Vas, vented at 33.0 Hz.

Fb = 33.0 Hz · F3 = 28.0 Hz · passband ripple 5.69 dB

American Bass VFL Comp 8 D2 · Fb 33.0 Hz, F3 28.0 Hz

Anechoic, before any cabin gain, with the 26 Hz subsonic filter already applied. The vent takes over below 33 Hz and the cone stops doing the work there, which is what holds travel down at the bottom of the passband.

03Ported vs Sealed

No sealed comparison is shown for this driver.

A ported-versus-sealed chart is only worth reading against a sealed box someone would actually build: the one we make for the driver, or the one its maker recommends. Neither exists for the American Bass VFL Comp 8 D2 — we do not build a sealed enclosure for it and American Bass publish no sealed volume for it — so rather than compare this cabinet against itself stuffed and sealed, a box no one would build, the comparison is left out.

04The 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 American Bass's published 13.0 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

P_Xmax = 1184 W with a 26 Hz subsonic · 411 W with none → the filter is worth 2.9×

1184 W · subsonic at 26 Hz, 24 dB/oct411 W · no subsonic filterXmax 13.0 mm one-way, published

Each trace touches the limit and no further, because each is drawn at the exact power that puts the cone on 13.0 mm. With a 26 Hz subsonic that takes 1184 W, reached first at 28 Hz. Take the filter away and the same cabinet reaches 13.0 mm on 411 W — the filter is worth 2.9× the safe power. A vent unloads the cone below tuning, so there is nothing holding it once the box stops loading: on a sealed build a subsonic filter is an improvement, here it is required equipment. The unfiltered trace is still rising where this chart stops at 20 Hz, so treat 411 W as a bound rather than a floor. Every wattage on this page is a MECHANICAL limit, not an electrical one. It is the power at which the cone runs out of linear travel in this cabinet, and nothing more. What the voice coil can dissipate as heat is a separate ceiling set by the driver, not by the box — American Bass rate this one at 600 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 600 W as the ceiling and the travel figures above as headroom. Final wired impedance, amplifier output and how long you hold the level are all electrical questions this graph does not answer.

Woofer Details

Materials

Material

Built From a Spec Sheet, Not a Sales Sheet

Every Proline X Professional 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 Professional 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.