Professional Series · Datasheet

Professional Series Ported Dual 8" Enclosure Sundown Audio X-Series v.3 8" X-8 · Dual 8" Ported enclosure

Net volume
2.18 Cubic Feet
Tuning
33.0 Hz
Max mounting depth
7.000 Inches (Sundown Audio Spec)
Cutout
7.375 Inches (Sundown Audio Spec)
External dimensions
34.00 Inches W × 14.00 Inches H × 17.50 Inches D
Front baffle
Three 3/4" MDF layers, 2.25" total | Woofer Flush-Mounted In The Outer Layer
Buy at Audio IntensityFactory-direct, ships from Tullahoma
  • Alignment: 2.18 cu ft net vented at 33.0 Hz. F3 28.4 Hz anechoic, 3.65 dB passband ripple
  • Driver: Sundown Audio X-Series v.3 8" X-8 D2, 800 W RMS, 19.0 mm Xmax, 48.50 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, 40.6 sq in front slot port beside the woofer with one bend along the back wall, port and excursion gated at 1600 W
  • Cabinet: 34.00" W x 14.00" H x 17.50" D, 59 lb, threaded insert kit included

Spec of record

Technical specifications

SeriesProline X Professional
Driver-Specific FitmentSundown Audio X-Series v.3 8" X-8 D2 (D2)
Enclosure TypePorted | Front-Firing Standard Box
External Width34.00 Inches
External Height14.00 Inches
External Depth17.50 Inches
Internal Volume (Gross)3.41 Cubic Feet
Internal Volume (Net After Displacement)2.18 Cubic Feet
Port TypeVertical Slot Beside The Woofer | Front Exit | One 90 Degree Bend Along The Back Wall
Port Geometry3.25 x 12.50 Inches, 40.6 Square Inches, 35.79 Inches Of Path
Port Area40.6 Square Inches
Port Tuning (Fb)33.0 Hz
Port Mouth1/2 In Roundover On All Four Edges, 57.4 Square Inches At The Face
Port Air Velocity23.4 m/s In The Channel, 16.6 m/s At The Mouth, At 1600 W (17.0 m/s Chuff Threshold)
Design Power Basis1600 W RMS (1.2 x The Driver Rating) For Port Velocity And Excursion
Predicted F328.4 Hz (Anechoic)
Passband Ripple3.65 dB (Anechoic)
Subsonic Filter26 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs48.50 Hz
Driver Qts0.486
Driver Qes / Qms0.533 / 5.542
Driver Vas3.933 Liters / 0.139 Cubic Feet
Driver Sd198.9 Square Centimeters
Driver Mms157.13 g
Driver BL23.22
Driver Re6.0 Ohm
Driver Xmax19mm (One-Way)
Driver Displacement0.13 Cubic Feet (Published by Sundown Audio)
Driver Sensitivity81.1 dB
Driver Power Handling800 Watts RMS
Driver Overall Diameter8.700 Inches (Sundown Audio Spec)
Mounting Depth Required7.000 Inches (Sundown Audio Spec)
Cutout Diameter7.375 Inches (Sundown Audio Spec)
Flush Mount Recess9.625 Inches In The Outer Layer
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC / Windowed Brace Front To Back Beside 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 ConfigurationD2
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 Power560-800 Watts RMS (Sundown Audio Rated: 800W RMS)
Carpet FinishPlush Black
Weight59 lb
ShippingUPS Ground Parcel, Included In The 48 States
Bundle OptionsEnclosure Only (Bring Your Own Sundown Audio X-Series v.3 8" X-8)
Warranty2-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA

Modelled response

Performance in this enclosure

Net airspace
2.18
cu ft
Tuning
33.0
Hz · Fb
Half power
28.4
Hz · F3, anechoic
Xmax at
4736
W RMS · 26 Hz subsonic
With NO filter
2146
W RMS · unfiltered
Port
16.6
m/s at the mouth · 1600 W

01Is this driver right for a ported box?

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

EBP = Fs ÷ Qes = 91.0
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EBP 91.0
Sundown Audio X-Series v.3 8" X-8 D2 · EBP 91.0
Between 50 and 100 a driver takes either load, and the choice becomes one of priorities rather than of physics. The Sundown Audio X-Series v.3 8" X-8 D2 reads 91.0. 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

2.18 cu ft net against a 7.9 L Vas, vented at 33.0 Hz.

Fb = 33.0 Hz  ·  F3 = 28.4 Hz  ·  passband ripple 3.65 dB
20 30 50 70 100 150 200 +16 +12 +8 +4 0 −4 −8 −12 −16 −20 −24 −28 FREQUENCY · Hz LEVEL · dB −3 dB Fb 33.0
Sundown Audio X-Series v.3 8" X-8 D2 · Fb 33.0 Hz, F3 28.4 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 Sundown Audio X-Series v.3 8" X-8 D2 — we do not build a sealed enclosure for it and Sundown 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 both cones exactly on Sundown's published 19.0 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off. Every power figure in this section is for the pair, split evenly.

PXmax = 4736 W with a 26 Hz subsonic  ·  2146 W with none  →  the filter is worth 2.2×
20 30 50 70 100 150 200 0 4 8 12 16 20 24 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 19.0 mm 4736 W reaches Xmax here
4736 W · subsonic at 26 Hz, 24 dB/oct2146 W · no subsonic filterXmax 19.0 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 19.0 mm. With a 26 Hz subsonic that takes 4736 W, reached first at 28 Hz. Take the filter away and the same cabinet reaches 19.0 mm on 2146 W — the filter is worth 2.2× 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 2146 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 1600 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 1600 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.

From the shop floor

Installer's take

I built this one for a pair of X-Series v.3 8" X-8 in a single shared chamber, which is how a dual ported box should be built: one volume, one port, both drivers loading the same air.

It gets the full Professional treatment, a 2.25 inch three-layer baffle with both woofers flush mounted in the outer layer, and the port on the left of the face.

Wiring is where a dual bites you. These are two 2 ohm coils each, so you can land on 1 ohm with all four coils in parallel, 2 ohms as two series pairs in parallel, or 8 ohms with everything in series. Check what your amplifier is rated for before you wire it, not after.

Sundown Audio publishes no mounting hole locations for the X-Series v.3 8" X-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.

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

Before you order

Questions

Why is this enclosure tuned to 33.0 Hz?

Both drivers share one chamber and one port rather than sitting in separate boxes, so the pair works against the whole volume and the port is sized for the pair rather than doubled. The port carries 40.6 square inches of area at 33.0 Hz, and the design power for the velocity and excursion checks is 1600 W for the pair. Passband ripple holds at 3.65 dB across the tuning, with F3 at 28.4 Hz. Tuning is chosen for in-car response rather than an anechoic curve: a vehicle adds roughly 12 dB per octave below about 45 Hz, and this tuning is where that sum comes out flattest across 25 to 60 Hz.

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

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 X-Series v.3 8" X-8 did not clear the port gate there. The calmest wedge port that fits that envelope is 13.0 square inches at 30.0 by 10.88 by 15.15 inches, and its mouth runs 21.0 metres per second at 800 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 524 W. The slot on this box reaches 40.6 square inches and holds the mouth at 16.6 metres per second at 1600 W. An under-ported box does not fail quietly. Air speed at the mouth rises with power; past the chuff line the flow turns turbulent and the port is audible on every note. The turbulence also chokes the port, so the box behaves as if it were tuned higher than it is, loses output near tuning, and lets the cone travel further below tuning than the design allows. This chassis is a full-size front-firing box on a 2.25 inch baffle built from three 3/4 inch layers with the woofer flush-mounted in the outer layer, a Sundown Audio logo acrylic, and a port and excursion budget checked at 1600 W. It carries a 2 year warranty against 1.

Threaded inserts or a kit?

Sundown Audio does not publish the mounting hole locations for the X-Series v.3 8" X-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 two kits, one per woofer. A dual cabinet ships two kits.

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 Sundown Audio X-Series v.3 8" X-8 at 58 percent of its usable travel at 1600 W.

Would a sealed box be better for me?

Not one we can show you. We do not build a sealed enclosure for the Sundown Audio X-Series v.3 8" X-8 and Sundown Audio mark it Not Recommended for a sealed enclosure, 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.

How does the front port work?

It is a vertical slot beside the woofer, the full height of the cavity, 3.25 inches wide and 40.6 square inches. It runs 10.50 inches to the back wall and turns once along it for 18.29 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 23.4 metres per second at 1600 W, 49 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 16.6 metres per second against the 17 metres per second threshold where a slot starts to chuff.

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

59 lb, 34.00" W x 14.00" H x 17.50" D external. It ships as a UPS parcel; the price includes shipping in the 48 states. Every Professional cabinet is priced the same way, by its size: this one is 4.82 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 59 lb parcel and checkout adds nothing. Do not add polyfill; it ships dry on purpose.

Is the X-Series v.3 8" X-8 included?

No. This is an enclosure only, cut for the Sundown Audio X-Series v.3 8" X-8 specifically: the 7.375 inch cutout, the 7.000 inch mounting depth allowance and the 2.18 cubic foot alignment all come from Sundown Audio's published parameters. It fits both coil versions; the alignment published here is the D2. Bring your own driver.

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