Proline X

Proline X PO 15-S W GUS | Single 15" Sealed Wedge Subwoofer Enclosure | Built for ResoNix GUS-15

Q: Can this enclosure be run down firing?

No. This is a trunk mounted wedge and it works in one orientation only. The tall face sits flat against the back of the rear seat, the cabinet tapers away toward the trunk lid, and the driver fires rearward into the trunk. There are no feet and no baffle clearance gap. If you need an enclosure that can run down fire with a GUS-15, the Proline X Micro Series Dual 15 Sealed Enclosure Built for ResoNix GUS-15 is a square stack fab cabinet that ships with feet and works in either orientation.

Q: Will a standard 15 inch subwoofer fit this enclosure?

No. The opening is cut direct fit to the ResoNix GUS-15 at 355mm, and the chamber volume is built around that driver. A standard 15 will not fit the opening and would not see the correct airspace if it did. That is what Performance Optimized means on this line. The enclosure is designed backward from one driver rather than sized to a diameter class.

Q: Why is the gross volume 1.42 cubic feet but the net acoustic volume 1.35?

Gross volume is the empty chamber. Net acoustic volume is what the driver actually loads into after its own body displaces air. The GUS-15 displaces 0.072 cubic feet. The chamber is built at 1.42 cubic feet gross, so after the driver goes in the working airspace is 1.348 cubic feet, which is ResoNix's published 1.35 target. The net figure is the one to enter into a modeling program.

Q: What alignment does the GUS-15 produce in this enclosure?

Calculated from ResoNix published Klippel measured parameters for the D4 coil, Fs 17.11 Hz, Qts 0.34, Vas 117.47 litres, this enclosure produces a Qtc of 0.687, a system resonance near 34.5 Hz, and an anechoic F3 of 35.6 Hz. That is a maximally flat alignment. Worth noting, F3 barely moves across the whole usable volume range, staying near 35 to 37 Hz from 0.8 all the way to 2.0 cubic feet. Enclosure size on this driver changes the character of the response rather than how deep it goes.

Q: Should I buy the single or the dual 15?

Start with the footprint. This single is 23.5 inches wide and 12.625 inches deep at the base. The dual is 36 inches wide, which will not clear in a lot of sedans. Both give each driver the same 1.35 cubic feet, so the alignment and the character are identical. The dual buys roughly 6 dB of output and doubles the power handling to 3000 watts. If the width fits and you want the output, take the dual. If it does not, one GUS-15 in the correct airspace is a better result than two in a compromised box.

Q: How much power can I run to this?

ResoNix rates the GUS-15 at 1500 watts RMS in its suggested enclosure, which is exactly what this cabinet provides. ResoNix is explicit that the GUS series is not deliberately underrated, so treat 1500 watts as the actual ceiling rather than a conservative figure. The terminal cup is pre wired with 12 gauge OFC and final impedance depends on the voice coil configuration you order from ResoNix.

Q: Does this include the ResoNix GUS-15 subwoofer?

No. This is an enclosure only product and the GUS-15 driver is purchased separately from ResoNix Sound Solutions. The enclosure ships with 8/32 threaded inserts installed, stainless machine screws, a pre wired terminal cup, and polyfill wall lining already installed. Audio Intensity is the exclusive enclosure builder for the ResoNix GUS platform.

SKU: PO 15-S W GUS

QUICK SPECS

Driver: ResoNix GUS-15 x1, direct fit only
Net Acoustic: 1.348 cu ft, ResoNix target 1.35
Alignment: Qtc 0.687, F3 35.6 Hz
Position: Trunk mount, tall face against rear seat
Firing: Rearward. No down fire option
Footprint: 23.5 in W x 12.625 in D at the base
Weight: 44 lb

Shipping Included No freight charges at checkout on orders to the lower 48. Alaska, Hawaii, and international orders are quoted live 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.

$ 399.99

Carpet

In Stock and Ready to Ship

Financing available — choose Shop Pay Installments at checkout.

Proline X PO 15-S W GUS | Single 15" Sealed Wedge Subwoofer Enclosure | Built for ResoNix GUS-15

Enclosure Type Sealed

External Dimensions 23.5" W x 17.5" H x 12.625" D at base tapering to 7.25" D at top

Net Volume 1.35cu ft

Tuning Frequency N/A

Cutout Diameter 355mm Direct Fit, ResoNix GUS-15

Front Panel Thickness 1.5"

Max Mounting Depth "

INSTALLER'S TAKE

Wire the terminal cup before you set this box in the trunk. Once the tall face is against the seat back there is no getting behind it, and on a wedge you cannot tip it forward to reach the cup the way you can with a square box. Run your speaker wire, land it, test continuity, then position.

Measure the base depth, not the top. The cabinet is 12.625 inches deep where it meets the trunk floor and only 7.25 at the top. The taper is there so the lid clears, but the number that decides whether it fits is the one at the floor, and trunk openings vary far more than trunk floors do.

We built this at 1.42 cubic feet gross for one reason. ResoNix publishes 1.35 net acoustic for the GUS-15 and the driver displaces 0.072. Do that subtraction and you land on 1.348. Most enclosures get sized to a convenient panel cut and the alignment falls where it falls. This one was cut from the number backward.

Do not add polyfill. There is already a light wall lining in there to kill internal reflections, and that is deliberate. Stuffing the box to a working density raises the effective volume and pushes the alignment off the target we just built to. If you want a different Qtc, change the box, not the fill.

Respect the 33mm clearance in front of the cone. Because this fires rearward into the trunk, that envelope is where your cargo lives. A jack, a case of water, a spare wheel leaning against the baffle, any of those will contact the surround at excursion. Plan the trunk around the box or you will be replacing a surround, and that is not a warranty item.

On power, 1500 watts RMS is the real number, not a conservative one. ResoNix is explicit that they do not underrate. Set gains with a scope or a meter, not by ear, and remember the GUS series stays composed right up until it does not.

Product Details

Proline X | Performance Optimized Wedge

One GUS-15, Sized to the Number ResoNix Published.

A sealed wedge cut for a single ResoNix GUS-15 and nothing else. It sits in the trunk with the tall face against the back of the rear seat and the driver firing rearward, using the length of the trunk instead of standing in the middle of it.

1.35 CU FT NET ACOUSTIC QTC 0.687 TRUNK MOUNT, REAR FIRING 1500W RMS DIRECT FIT GUS-15 BUILT IN TULLAHOMA, TN

Read This First

This Is Not a Down Fire Enclosure

The wedge works in one orientation: tall face flat against the rear seat back, taper running out toward the trunk lid, driver firing rearward. There are no feet, no baffle clearance gap, and no down fire option on this cabinet.

It is also cut direct fit to the GUS-15 at a 355mm opening. A standard 15 will not fit, and would not see the correct airspace if it did.

Built Backward From One Published Number

ResoNix specifies 1.35 cubic feet of net acoustic airspace for the GUS-15, the volume that produces a maximally flat sealed alignment. This cabinet is built at 1.42 cubic feet gross. Subtract the driver's 0.072 cubic feet of displacement and the GUS-15 sees 1.348 cubic feet.

That is not close to the target. That is the target. The cabinet was sized from the number rather than the number being quoted after the fact, which is the whole idea behind the Optimized line.

Why a Wedge

Packaging

It Uses the Trunk Lengthwise

Tall face against the rear seat, tapering down as it runs out toward the lid. The cabinet claims the deep space at the base of the trunk and gives height back where the lid closes, so you keep usable trunk.

The Trunk Is Part of the System

Firing rearward means output loads into the trunk volume and reaches the cabin through the rear seat and deck. That path is what gives a trunk mounted subwoofer its weight.

Localization

Harder to Point At

Because the driver does not radiate straight into the cabin, the low end arrives through the structure rather than as a beam from behind your head, which makes keeping the stage forward easier.

Footprint

Half the Width of the Dual

At 23.5 inches wide this fits vehicles the 36 inch dual 15 cannot. One GUS-15 in the right airspace beats two in the wrong one.

How It Is Built

Cabinet

Cut on our ShopSabre CNC from Langboard Elite MDF and assembled with dado and V groove joinery over 0.75 inch panels, with a double baffle at 1.5 inches. Angled panel meets are cut as V joints so the faces close on a machined bevel rather than a filled seam.

Mounting Pattern

The GUS-15 is in the Proline X CAD library, drawn from the manufacturer's own STEP file. The 355mm cutout and the nutsert locations are machined in the same operation from the same origin, so the holes cannot drift relative to each other. 8/32 threaded inserts installed with stainless machine screws supplied, matched to the driver's 375mm bolt circle and its eight 6.5mm holes.

Wiring and Damping

Proline X ABS and carbon fiber composite terminal cup, side mounted, pre wired with 12 gauge OFC. Polyfill is installed as a light wall lining to control internal reflections without altering the acoustic volume, because adding fill density would shift the alignment off the 1.35 target.

Finish

Plush black carpet with a black acrylic badge on the woofer face.

Fitment

External dimensions are 23.5 inches wide by 17.5 inches tall, with depth running 12.625 inches at the base tapering to 7.25 inches at the top. Maximum driver mounting depth is 7 inches, comfortable for the GUS-15.

Front clearance. ResoNix specifies 33mm minimum clearance in front of the GUS-15. At more than 25mm of Klippel verified one way excursion that is the operational envelope of the suspension, not optional headroom. Since the driver fires rearward into the trunk, anything you load behind the box has to stay outside that envelope.

Enclosure Performance

Calculated from ResoNix's published Klippel measured parameters for the GUS-15 D4 coil: Fs 17.11 Hz, Qts 0.34, Vas 117.47 litres. Nothing here is estimated.

Net Volume	Qtc	fc	F3	Character
0.80 cu ft, ResoNix minimum	0.846	42.6 Hz	36.7 Hz	Tighter, more upper bass
1.35 cu ft, this enclosure	0.687	34.5 Hz	35.6 Hz	Maximally flat. The target.
2.00 cu ft, ResoNix maximum	0.596	30.0 Hz	36.6 Hz	Overdamped, more headroom

Look at the F3 column, not the Qtc column. Across the entire usable range, from ResoNix's minimum 0.8 up to their maximum 2.0 cubic feet, F3 moves about one hertz. Enclosure volume on this driver changes the shape of the response, not how deep it plays. Going bigger buys damping and headroom and costs upper bass, but buys no extension. That falls straight out of a 17 Hz Fs paired with a 0.34 Qts.

What flat means in a trunk. These figures are anechoic. Installed in a vehicle, cabin transfer function lifts the bottom octave regardless of alignment, and a rear firing trunk mount adds the loading of the trunk on top of that. In practice the in-car response will be considerably warmer than the curve above.

Run your own numbers with the Sealed Box Calculator.

Full dimensions, cutout, mounting depth, and hardware details are listed under the Enclosures tab.

Cut for the GUS-15. Built in Tennessee.

Enclosure only. The ResoNix GUS-15 driver is purchased separately from ResoNix Sound Solutions. Built to order in Tullahoma, Tennessee on our own CNC equipment. Questions on fitment or amplifier matching, call or text 931-563-5151.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	ResoNix GUS-15, quantity 1. Direct fit, no other driver
Configuration	Single 15 inch 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	23.5 in
External Height	17.5 in at the seat face
External Depth	12.625 in at the base, tapering to 7.25 in at the top
Internal Volume, Gross	1.42 cu ft
Internal Volume, Net Acoustic	1.348 cu ft after 0.072 cu ft driver displacement
ResoNix Published Target	1.35 cu ft for maximally flat alignment
Calculated Qtc	0.687
Calculated fc	34.5 Hz
Calculated F3	35.6 Hz, anechoic
Woofer Opening	355mm direct fit
Max Mounting Depth	7 in
Min Front Clearance	33mm
Driver Power Handling	1500 W RMS in suggested enclosure
Material	Langboard Elite MDF
Construction	CNC cut, dado and V groove joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in, double baffle
Driver Mounting	8/32 threaded inserts, stainless machine screws included, 375mm bolt circle
Terminal Cup	Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
Damping	Light polyfill wall lining, does not alter acoustic volume
Carpet	Plush black
Badge	Woofer face mounted, black lasered acrylic
Weight	44 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

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.