Proline X

Professional Series Ported 15" Enclosure | Image Dynamics IDMAX15 V4

Q: Do I need a subsonic filter?

Yes, at 24 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 Image Dynamics IDMAX15 V4 at 36 percent of its usable travel at 720 W.

Q: Would a sealed box be better for me?

The two alignments converge at the bottom of the band on this driver rather than crossing cleanly, so there is no meaningful subsonic advantage either way. Above 25 Hz the vent is the louder of the two for the same power. The Performance Graphs tab plots this cabinet, 2.85 cubic feet vented at 30.0 Hz, against Image Dynamics's recommended sealed box, 2.00 cu ft (2.00 gross, 1.74 net after the driver), so you can judge it yourself.

Q: How does the front port work?

It is a vertical slot beside the woofer, the full height of the cavity, 2.75 inches wide and 45.4 square inches. It runs 9.50 inches to the back wall and turns once along it for 20.46 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 10.4 metres per second at 720 W, 31 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 7.2 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?

70 lb, 36.00" W x 18.00" H x 16.00" 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 6.00 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 70 lb parcel and checkout adds nothing. The Performance Optimized 15 inch ported wedge is $499.99. The $102 difference is the larger box and the port this driver needs to run at its rating. Do not add polyfill; it ships dry on purpose.

Q: Is the IDMAX15 V4 included?

No. This is an enclosure only, cut for the Image Dynamics IDMAX15 V4 specifically: the 14.764 inch cutout, the 10.433 inch mounting depth allowance and the 2.85 cubic foot alignment all come from Image Dynamics's published parameters. It fits both coil versions; the alignment published here is the D2. Bring your own driver.

SKU: Pro 15-P IDMAX

QUICK SPECS

Alignment: 2.85 cu ft net vented at 30.0 Hz. F3 29.1 Hz anechoic, 5.16 dB passband ripple
Driver: Image Dynamics IDMAX15 V4 D2, 600 W RMS, 22.0 mm Xmax, 30.00 Hz Fs
Build: Front-firing standard box, 2.25" three-layer baffle with the woofer flush-mounted in the outer layer, Image Dynamics logo acrylic, dado joinery, 45.4 sq in front slot port beside the woofer with one bend along the back wall, port and excursion gated at 720 W
Cabinet: 36.00" W x 18.00" H x 16.00" D, 70 lb, threaded inserts pressed into the baffle on the published 15.551 inch bolt circle

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.

$ 601.99

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Complete Your System

Image Dynamics Image Dynamics IDMAX15 V4 15 inch Subwoofer $ 679.99

Image Dynamics Image Dynamics SQ1200.1D 1200W Mono Block Amplifier $ 504.99

Professional Series Ported 15" Enclosure | Image Dynamics IDMAX15 V4

$ 601.99

Enclosure Type Ported

External Dimensions 36.00" W x 18.00" H x 16.00" D

Gross Volume 4.28 cu ft

Net Volume 2.85 cu ft

Tuning Frequency 30.0 Hz

Port Area 45.4 Square Inches

Shipping Weight 78 lbs

INSTALLER'S TAKE

I built this box because the IDMAX15 kept being asked for and nothing in the trunk lines would hold it. The motor is deep and the frame is wide, so it gets the full-size standard box: three layers of baffle, the flange flush in the outer one, the port beside it on the front face.

The port is wide on purpose. At one and a half times the rated 600 watts the air in the channel is still well under the point where a slot starts to chuff, so you can run a real amplifier on this without hearing the port. Set your subsonic at 21 Hz and leave it there.

Wire the D2 series for 4 ohms unless the amplifier is rated for 1 ohm. Six hundred watts is the coil's thermal limit and it binds long before the cone runs out of travel in this box, so heat is what you manage, not excursion.

The Performance Optimized wedge is the smaller and cheaper box, and I try it first for every driver. The IDMAX15 V4 does not fit it, so this is the box.

It ships dry. Do not add polyfill to a ported box.

Product Details

Proline X Professional 15" Ported

The fifteen that needs a full-size box, vented near 27 Hz on a three-layer baffle

2.85 cu ft net Tuned 30.0 Hz F3 29.1 Hz 2.25" three-layer baffle Cut for the IDMAX15 V4 Built in Tennessee

2.85cu ft net

30.0Hz tuning

29.1Hz F3 anechoic

45.4sq in port area

Why this driver is vented at 30.0 Hz

The IDMAX15 V4 carries 10.433 inches of mounting depth and a 16 inch frame, and neither trunk chassis will take it: the ported Down Fire caps at 8.50 inches of height and the wedge has no fifteen-inch ported height it fits. The Professional box stands 18 inches tall, flush-mounts the flange in a 2.25 inch baffle built from three 3/4 inch layers, and gives the motor the depth it needs. It gets 2.72 cubic feet net, vented at 26.5 Hz, in a 36 inch wide cabinet beside the front port.

Image Dynamics publish a Qts of 0.95 at 30 Hz for the D2 coil, and that figure is genuine: their Qes and Qms reproduce it and the motor constants agree. A driver that damped wants a large box and a low vent, and their own manual says so, recommending 3.0 cubic feet gross at 27 Hz for the Universal alignment. This cabinet lands on it: 4.12 gross, 2.72 net after the driver, port and braces, vented at 26.5 Hz, which is where the in-car curve comes out flattest. Passband ripple sits at 4.46 dB, and that number is the driver's Q rather than the box; tuning higher or lower makes it worse, not better.

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.

Image Dynamics logo acrylic

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

Mounting

Threaded inserts pressed into the baffle on the published 15.551 inch bolt circle, stainless machine screws included.

Port gated at 720 W

The 45.4 square inch slot beside the woofer is sized so the channel runs 10.4 metres per second and the mouth 7.2 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 9.50 inches along its wall and turns once along the back wall for another 20.46 inches, which is why a 30.0 Hz tuning fits a 16.00 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 IDMAX15 V4 did not clear the ripple 5.51 dB over 4.5 gate there: the nearest wedge that fits is 24.5 by 11.25 by 17.98 inches with a 23.0 square inch port, and no tuning, width or depth inside that envelope passes. The slot on this box reaches 45.4 square inches.

What the price covers

Every Professional cabinet is priced the same way, by its size: this one is 6.00 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 70 lb parcel and checkout adds nothing. The Performance Optimized 15 inch ported wedge is $499.99. The $102 difference is the larger box and the port this driver needs to run at its rating.

What Image Dynamics recommend

Image Dynamics publish a vented box for the Image Dynamics IDMAX15 V4 at 2.00 cubic feet gross including the port, tuned to 30.0 Hz. This cabinet holds 4.28 cubic feet gross and tunes to 30.0 Hz. The extra air lowers the low corner rather than raising output at tuning.

The cabinet

36.00" W x 18.00" H x 16.00" 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 36 by 18 Professional envelope for a single 15, with the depth the motor needs. It ships as a parcel.

The two coils publish different Vas figures, 77.5 litres for the D2 and 84.8 for the D4, which a shared cone and suspension cannot produce. The D2 column is the published alignment here and the cabinet fits either coil. Image Dynamics recommend a sealed box for this driver; the ported Professional gives up nothing in control above 30 Hz and adds the output the motor is rated for, provided the subsonic filter is set.

The numbers to respect

Set a 24 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in place the cone reaches 8.0 mm of its 22.0 mm at 720 W.

Enclosure Specifications

Series	Proline X Professional
Driver-Specific Fitment	Image Dynamics IDMAX15 V4 D2 (Dual 2 Ohm)
Enclosure Type	Ported \| Front-Firing Standard Box
External Width	36.00 Inches
External Height	18.00 Inches
External Depth	16.00 Inches
Internal Volume (Gross)	4.28 Cubic Feet
Internal Volume (Net After Displacement)	2.85 Cubic Feet
Port Type	Vertical Slot Beside The Woofer \| Front Exit \| One 90 Degree Bend Along The Back Wall
Port Geometry	2.75 x 16.50 Inches, 45.4 Square Inches, 36.46 Inches Of Path
Port Area	45.4 Square Inches
Port Tuning (Fb)	30.0 Hz
Port Mouth	1/2 In Roundover On All Four Edges, 65.6 Square Inches At The Face
Port Air Velocity	10.4 m/s In The Channel, 7.2 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	29.1 Hz (Anechoic)
Passband Ripple	5.16 dB (Anechoic)
Subsonic Filter	24 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs	30.00 Hz
Driver Qts	0.952
Driver Qes / Qms	1.203 / 4.810
Driver Vas	77.540 Liters / 2.738 Cubic Feet
Driver Sd	935.0 Square Centimeters
Driver Mms	386.00 g
Driver BL	15.10
Driver Re	3.6 Ohm
Driver Xmax	22mm (One-Way)
Driver Displacement	0.26 Cubic Feet (Published by Image Dynamics)
Driver Sensitivity	87.2 dB
Driver Power Handling	600 Watts RMS
Driver Overall Diameter	16.016 Inches (Image Dynamics Spec)
Mounting Depth Required	10.433 Inches (Image Dynamics Spec)
Cutout Diameter	14.764 Inches (Image Dynamics Spec)
Flush Mount Recess	17.000 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 Image Dynamics Logo Insert, Outer Layer, Standard
Mounting Hardware	Threaded Inserts On The Published 15.551 In Bolt Circle \| Stainless Machine Screws Included
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 (Image Dynamics Rated: 600W RMS)
Carpet Finish	Plush Black
Shipping Weight	78 lb
Shipping	UPS Ground Parcel, Included In The 48 States
Bundle Options	Enclosure Only (Bring Your Own Image Dynamics IDMAX15 V4)
Warranty	2-Year Limited (Enclosure)
Manufactured	Tullahoma, Tennessee, USA

Performance Graphs

Net airspace

2.85

cu ft

Tuning

30.0

Hz · Fb

Half power

29.1

Hz · F3, anechoic

Xmax at

5420

W RMS · 24 Hz subsonic

With NO filter

1088

W RMS · unfiltered

Port

7.2

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 = 24.9

Image Dynamics IDMAX15 V4 D2 · EBP 24.9

Under 50 the raw number leans sealed. The Image Dynamics IDMAX15 V4 D2 reads 24.9, so this is a ported build against the grain of its own EBP: it works because the alignment is tuned for in-car response rather than for an anechoic curve, and because the cabinet holds port area and volume the driver can actually use.

02What the box does to it

2.85 cu ft net against a 77.5 L Vas, vented at 30.0 Hz.

Fb = 30.0 Hz · F3 = 29.1 Hz · passband ripple 5.16 dB

Image Dynamics IDMAX15 V4 D2 · Fb 30.0 Hz, F3 29.1 Hz

Anechoic, before any cabin gain, with the 24 Hz subsonic filter already applied. The vent takes over below 30 Hz and the cone stops doing the work there, which is what holds travel down at the bottom of the passband.

03Perceived Ported vs Sealed

This cabinet, 2.85 cu ft net vented at 30.0 Hz, against Image Dynamics's recommended sealed box, 2.00 cu ft (2.00 gross, 1.74 net after the driver).

Ported Fb 30.0 Hz · the 1.74 cu ft sealed box runs Qtc 1.53, Fc 48 Hz

Ported · this cabinet, 2.85 cu ft, Fb 30.0 HzImage Dynamics's recommended sealed, 1.74 cu ft net, Qtc 1.53

Shaded blue is where the ported alignment is louder for the same power, orange where the sealed one is. The sealed curve is Image Dynamics's recommended sealed box, 2.00 cu ft (2.00 gross, 1.74 net after the driver), not this cabinet with the port blocked: two different boxes, because that is the choice a buyer actually has. Across 25 to 60 Hz the vent is worth 5.5 dB at its widest and 3.5 dB on average. This is the anechoic picture, which is not what you hear in a car.

04Real World Ported vs Sealed

The same two boxes with cabin gain applied, 45 Hz corner, 18 dB ceiling.

Flatness across 25–60 Hz: ported 1.2 dB spread, the 1.74 cu ft sealed box 3.5 dB

Ported, in-car · 1.2 dB spreadImage Dynamics's recommended sealed, 1.74 cu ft net, in-car · 3.5 dB spread

Cabin gain lifts both boxes by the same amount, so the gap between them does not change: what changes is the shape each one ends up with. A car pressurises below roughly 45 Hz, which fills in the sealed box's shallower rolloff and over-drives it where the ported box is already flat. Across 25 to 60 Hz, the band kick and bass fundamentals occupy, this alignment holds 1.2 dB of spread against 3.5 dB for Image Dynamics's recommended sealed box, 2.00 cu ft (2.00 gross, 1.74 net after the driver). Flatter is the whole point of tuning this high. The two alignments converge at the bottom of the band rather than crossing cleanly, so there is no meaningful subsonic advantage either way here. Cabin gain here is a house assumption, not a measurement of your vehicle.

05The 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 Image Dynamics's published 22.0 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

P_Xmax = 5420 W with a 24 Hz subsonic · 1088 W with none → the filter is worth 5.0×

5420 W · subsonic at 24 Hz, 24 dB/oct1088 W · no subsonic filterXmax 22.0 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 22.0 mm. With a 24 Hz subsonic that takes 5420 W, reached first at 47 Hz. Take the filter away and the same cabinet reaches 22.0 mm on 1088 W — the filter is worth 5.0× 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 1088 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 — Image Dynamics 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

Image Dynamics pitches IDMAX at the buyer who wants low frequency detail and high output together. What separates the 15 from the IDMAX 10 and 12 is the motor and coil: a 575 oz extended Y-35 structure and a 2.5 inch flat wound aluminium coil against their 2 inch coil and 400 oz motor. The cone assembly is field replaceable without glue. Image Dynamics states this driver is made in the USA. This enclosure is cut for 10.43 in of mounting depth and a 14.75 in cutout, taken from None'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.

Driver	Image Dynamics IDMAX15 V4 D2
Coil Options	Dual 2 Ohm or Dual 4 Ohm
Voice Coil Diameter	2.5 in, Flat Wound Aluminum, 60 mm Winding Height
Coil Former	BASV, With An Aluminum Neck Joint
Cone	Glass Fiber And Pulp
Surround	Parabolic Santoprene
Spider	Nomex
Motor	Extended Y-35 Ferrite, 575 oz
Power, RMS	600 W
Peak Power	1200 W
Sensitivity	86 dB, 1W/1m
Mounting Depth	10.43 in
Cutout Diameter	14.75 in
Frame Outside Diameter	16.22 in
Driver Displacement	0.26 cu ft
Driver Weight	43 lb
Driver Warranty	1 Year, Authorized US Dealer

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.