Proline X Pro 10-P SDDN10 Professional Series ported enclosure, front baffle with slot port and branded gloss black acrylic insert, 30 by 14 inches, 56.2 square inches of port area.
Proline X Pro 10-P SDDN10 Professional Series ported enclosure, front baffle with slot port and branded gloss black acrylic insert, 30 by 14 inches, 56.2 square inches of port area.

Proline X

Professional Series Ported 10" Enclosure | Sundown Audio SDDN 10" Limited Edition Competition

SKU: Pro 10-P SDDN10

QUICK SPECS
  • Alignment: 3.11 cu ft net vented at 32.5 Hz. F3 28.1 Hz anechoic, 5.55 dB passband ripple
  • Driver: Sundown Audio SDDN 10" Limited Edition Competition D1, 3500 W RMS, 35.0 mm Xmax, 38.72 Hz Fs
  • Build: Front-firing standard box, 2.25" three-layer baffle with the woofer flush-mounted in the outer layer, Sundown Audio logo acrylic, dado joinery, 56.2 sq in front slot port beside the woofer with one bend along the back wall, port and excursion gated at 3500 W
  • Cabinet: 30.00" W x 14.00" H x 26.38" D, 68 lb, threaded insert kit included
Shipping Icon
Shipping Included No freight charges at checkout on US orders. International orders are quoted live carrier rates at checkout.
USA Flag Rounded
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.
$ 627.99
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Proline X Pro 10-P SDDN10 Professional Series ported enclosure, front baffle with slot port and branded gloss black acrylic insert, 30 by 14 inches, 56.2 square inches of port area.

Professional Series Ported 10" Enclosure | Sundown Audio SDDN 10" Limited Edition Competition

Regular price $ 627.99
Sale price $ 627.99 Regular price
Unit price

More enclosures cut for Sundown Audio subwoofers: Sundown Audio Subwoofer Boxes

Enclosure Type Ported
External Dimensions 30.00" W x 14.00" H x 26.38" D
Gross Volume 4.65 cu ft
Net Volume 3.11 cu ft
Tuning Frequency 32.5 Hz
Port Area 56.2 Square Inches
Shipping Weight 76 lbs
INSTALLER'S TAKE

I built this box on Sundown's own published numbers for the SDDN10, and I want to be upfront about the one number I cannot verify: Sundown lists 35 millimeters of Xmax without saying whether that is peak or peak to peak, so I am carrying it as published rather than certifying the excursion math behind it.

The port here is modeled clean past the coil's own 3500 watt rating, out to 3671 watts, but the mouth runs at 16.6 meters per second against the 17 meter per second point where a slot starts to chuff, close enough that I would call this a marginal build rather than a comfortable one.

Wire the D1 coil in series for 2 ohms or parallel for 0.5 ohms. A parallel load under 1 ohm needs an amplifier rated for it.

Sundown Audio publishes no mounting hole locations for the SDDN 10" Limited Edition Competition, 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 SDDN 10" Limited Edition Competition: the calmest port that fits that envelope goes noisy at about 295 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 28 Hz.

Product Details
Enclosure Specifications
Performance Graphs
Woofer Details
Materials
Product Details

Proline X Professional 10" Ported

A ported ten-inch box built to Sundown's own numbers for the SDDN 10 Limited Edition Competition

3.11 cu ft net Tuned 32.5 Hz F3 28.1 Hz 2.25" three-layer baffle Cut for the SDDN 10" Limited Edition Competition Built in Tennessee
3.11cu ft net
32.5Hz tuning
28.1Hz F3 anechoic
56.2sq in port area

Why this driver is vented at 32.5 Hz

The Sundown Audio SDDN 10 inch Limited Edition Competition D1 carries an 11.66 inch frame and an 11.17 inch mounting depth, and this cabinet gives it 3.110 cubic feet net, vented at 32.5 Hz through a 56.2 square inch port beside the woofer on the front face. F3 lands at 28.1 Hz with 5.55 dB of passband ripple. The 30.0 by 14.0 by 26.4 inch enclosure carries a single 90 degree bend in the port.

Threaded insert kit ships with this box. Sundown Audio does not publish the mounting hole locations for the SDDN 10" Limited Edition Competition, 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 gate here is measured at the coil's rated power, 3500 W, and the port stays clean past that rating, modeled to 3671 W before mouth velocity becomes the limiting factor. Sundown publishes 35.0 mm of Xmax for the SDDN10 without stating whether the figure is peak or peak to peak, so the excursion side of this build's math is carried as published rather than certified. Ripple across the passband holds at 5.55 dB.

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.

Sundown Audio logo acrylic

A glossy black acrylic insert with the Sundown Audio 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 3500 W

The 56.2 square inch slot beside the woofer is sized so the channel runs 21.9 metres per second and the mouth 16.6 metres per second at the driver's rated power, under the 17 metres per second where a slot starts to chuff. The channel runs 18.12 inches along its wall and turns once along the back wall for another 8.26 inches, which is why a 32.5 Hz tuning fits a 26.38 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 SDDN 10" Limited Edition Competition did not clear the port gate there. The calmest wedge port that fits that envelope is 8.5 square inches at 16.5 by 13.00 by 17.91 inches, and its mouth runs 58.5 metres per second at 3500 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 295 W. The slot on this box reaches 56.2 square inches and holds the mouth at 16.6 metres per second at 3500 W.

What the price covers

Every Professional cabinet is priced the same way, by its size: this one is 6.41 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 68 lb parcel and checkout adds nothing.

What Sundown Audio recommend

Sundown Audio publish a vented box for the SDDN 10" Limited Edition Competition at 1.50 cubic feet on a basis they do not state, tuned to 32.0 Hz. This cabinet holds 3.11 cubic feet net and tunes to 32.5 Hz. They call for a port area of 24 sq in. The extra air lowers the low corner rather than raising output at tuning.

The cabinet

30.00" W x 14.00" H x 26.38" 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. This is our single-ten ported envelope built around the SDDN10's own frame and motor depth. It ships as a parcel.

Sundown publishes 35.0 mm of Xmax for the SDDN10 D1 with no basis stated; if that number is peak to peak rather than peak, actual one-way travel is closer to half of it, and the excursion gate behind this build is not something we are willing to certify from that figure alone. Separately, this port's mouth runs at 16.6 m/s against the 17 m/s point where a slot starts to chuff, close enough that the design counts as a marginal call rather than a comfortable one. If the Xmax figure reads high, the risk on the excursion side is a cone that unloads or bottoms under real power before the port itself becomes audible. Sundown Audio does not publish the mounting hole locations for the SDDN 10" Limited Edition Competition, 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 12.4 mm of its 35.0 mm at 3500 W.

Enclosure Specifications
SeriesProline X Professional
Driver-Specific FitmentSundown Audio SDDN 10" Limited Edition Competition D1 (D1)
Enclosure TypePorted | Front-Firing Standard Box
External Width30.00 Inches
External Height14.00 Inches
External Depth26.38 Inches
Internal Volume (Gross)4.65 Cubic Feet
Internal Volume (Net After Displacement)3.11 Cubic Feet
Port TypeVertical Slot Beside The Woofer | Front Exit | One 90 Degree Bend Along The Back Wall
Port Geometry4.50 x 12.50 Inches, 56.2 Square Inches, 34.63 Inches Of Path
Port Area56.2 Square Inches
Port Tuning (Fb)32.5 Hz
Port Mouth1/2 In Roundover On All Four Edges, 74.2 Square Inches At The Face
Port Air Velocity21.9 m/s In The Channel, 16.6 m/s At The Mouth, At 3500 W (17.0 m/s Chuff Threshold)
Design Power Basis3500 W RMS (1.2 x The Driver Rating) For Port Velocity And Excursion
Predicted F328.1 Hz (Anechoic)
Passband Ripple5.55 dB (Anechoic)
Subsonic Filter26 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs38.72 Hz
Driver Qts0.247
Driver Qes / Qms0.262 / 4.428
Driver Vas7.490 Liters / 0.265 Cubic Feet
Driver Sd366.1 Square Centimeters
Driver Mms429.24 g
Driver BL28.14
Driver Re2.0 Ohm
Driver Xmax35mm (One-Way)
Driver Displacement0.25 Cubic Feet (Published by Sundown Audio)
Driver Sensitivity83.9 dB
Driver Power Handling3500 Watts RMS
Driver Overall Diameter11.660 Inches (Sundown Audio Spec)
Mounting Depth Required11.170 Inches (Sundown Audio Spec)
Cutout Diameter10.100 Inches (Sundown Audio Spec)
Flush Mount Recess12.625 Inches In The Outer Layer
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC / Two Windowed Braces Front To Back Either Side Of The Woofer
JoineryDado Joinery (CNC-Cut), Flat Panels
Front Baffle ConstructionThree 3/4" MDF layers, 2.25" total | Woofer Flush-Mounted In The Outer Layer
Baffle Layers3
AcrylicGlossy Black Sundown Audio Logo Insert, Outer Layer, Standard
Mounting HardwareThreaded Insert Kit Included: 8-12 Inserts, Drill Bit, 2.5 In Allen-Head Screws, Allen Key, Gasket Tape
Voice Coil ConfigurationD1
Terminal CupProline X ABS/Carbon Fiber Composite | Back Panel, Terminal-Cup Side | 12g OFC Pre-Wired
DampingNone - Ships Dry. Polyfill Detunes A Ported Enclosure
Recommended Power2450-3500 Watts RMS (Sundown Audio Rated: 3500W RMS)
Carpet FinishPlush Black
Shipping Weight76 lb
ShippingUPS Ground Parcel, Included In The 48 States
Bundle OptionsEnclosure Only (Bring Your Own Sundown Audio SDDN 10" Limited Edition Competition)
Warranty2-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA
Performance Graphs
Net airspace
3.11
cu ft
Tuning
32.5
Hz · Fb
Half power
28.1
Hz · F3, anechoic
Xmax at
27710
W RMS · 26 Hz subsonic
With NO filter
9444
W RMS · unfiltered
Port
16.6
m/s at the mouth · 3500 W

01Is this driver right for a ported box?

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

EBP = Fs ÷ Qes = 147.8
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EBP 147.8
Sundown Audio SDDN 10" Limited Edition Competition D1 · EBP 147.8
Above 100 the motor is asking for a vent. The Sundown Audio SDDN 10" Limited Edition Competition D1 reads 147.8, so a ported load is the alignment it was designed around, not a compromise applied to it.

02What the box does to it

3.11 cu ft net against a 7.5 L Vas, vented at 32.5 Hz.

Fb = 32.5 Hz  ·  F3 = 28.1 Hz  ·  passband ripple 5.55 dB
20 30 50 70 100 150 200 +8 +4 0 −4 −8 −12 −16 −20 −24 −28 −32 FREQUENCY · Hz LEVEL · dB −3 dB Fb 32.5
Sundown Audio SDDN 10" Limited Edition Competition D1 · Fb 32.5 Hz, F3 28.1 Hz
Anechoic, before any cabin gain, with the 26 Hz subsonic filter already applied. The vent takes over below 32 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 Sundown Audio SDDN 10" Limited Edition Competition D1 — we do not build a sealed enclosure for it and Sundown mark it Not Recommended for a sealed enclosure — 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 Sundown's published 35.0 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

PXmax = 27710 W with a 26 Hz subsonic  ·  9444 W with none  →  the filter is worth 2.9×
20 30 50 70 100 150 200 0 8 16 24 32 40 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 35.0 mm 27710 W reaches Xmax here
27710 W · subsonic at 26 Hz, 24 dB/oct9444 W · no subsonic filterXmax 35.0 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 35.0 mm. With a 26 Hz subsonic that takes 27710 W, reached first at 28 Hz. Take the filter away and the same cabinet reaches 35.0 mm on 9444 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 9444 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 — Sundown rate this one at 3500 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 3500 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
A limited edition competition driver designed in house by Sundown's founder. Sundown does not recommend it sealed and lists ported and sixth order enclosures only, which is why it lands in the Professional Series rather than a wedge. This enclosure is cut for 11.17 in of mounting depth and a 10.10 in cutout, taken from Sundown Audio's published figures rather than measured off a sample. Where a rating below carries no reference condition, that is because the maker does not state one, and it is left as they print it.
DriverSundown Audio SDDN 10" Limited Edition Competition
Coil OptionsDual 1 Ohm
Voice Coil Diameter3.3 in, 80 mm winding height
Coil FormerAluminum
ConeMega V2, carbon cone offered as an upgrade
Spider5 Layer
Lead WiresDual Layer Tinsel On Dual 8 AWG Terminals
Motor1336 oz (83.5 lb) With Integrated Thermal Ventilation, Cross Cut Pole Piece With A Neodymium Cap
Motor Diameter9.84 in
Power, RMS3500 W
Peak Power7000 W
Sensitivity83.94 dB, Sensitivity, reference condition not stated by Sundown
Mounting Depth11.17 in
Cutout Diameter10.10 in
Frame Outside Diameter11.66 in
Driver Displacement0.25 cu ft
Driver Warranty2 Year Limited, Authorized Dealer Purchase, Original Owner
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

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.

Handcrafted in USA

Handcrafted in USA

Hand-assembled at our facility in Tullahoma, TN. Every enclosure is inspected before it ships.

Tuned to the Build

Tuned to the Build

Internal volume and port geometry are calculated to spec and CNC-cut to exact dimensions. The box performs the same way every time.

Frequently Asked Questions

Why is this enclosure tuned to 32.5 Hz?

Why is this a Professional build and not a Performance Optimized box?

Threaded inserts or a kit?

Do I need a subsonic filter?

Would a sealed box be better for me?

How does the front port work?

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

Is the SDDN 10" Limited Edition Competition included?

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