Proline X PO 11-S W BM11 sealed wedge, front baffle with gloss black insert and pre-wired leads, 16.74 by 14 inches.

Performance Optimized Wedge Sealed 11" Enclosure | Stereo Integrity BM-11 Single 11" Sealed enclosure

Net volume: 0.40 cu ft
Max mounting depth: 3.071 in required
Cutout: 10.00 in
External dimensions: 16.74 in W × 14 in at the seat face H × 9.81 in at the base D
Front baffle: 1.5 in, double baffle

Best For: Stereo Integrity BM-11 Trunk-Fit Builds
Net Volume: 0.40 cu ft (0.44 cu ft Gross)
Alignment: Qtc 1.432, fc 58.8 Hz, F3 41.5 Hz
Driver Match: BM-11
Impedance: dual 2 ohm
Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts

Technical specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	Stereo Integrity BM-11, quantity 1. Direct fit
Configuration	Single 11 inch, single chamber 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	16.74 in
External Height	14 in at the seat face
External Depth	9.81 in at the base, tapering to 4.71 in at the top
Internal Volume, Gross	0.44 cu ft
Internal Volume, Net Acoustic	0.40 cu ft
Alignment	Qtc 1.432, fc 58.8 Hz, F3 41.5 Hz anechoic
Driver Cutout	10.00 in
Driver Mounting Depth	3.071 in required
Power Handling	500 watts RMS
Impedance	Dual 2 ohm
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in, double baffle
Internal Bracing	Windowed C brace
Driver Mounting	Threaded inserts at every mounting location, stainless machine screws included
Terminal Cups	One 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
Weight	19.3 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance in this enclosure

Net airspace

0.40

cu ft per chamber

System Qtc

1.43

sealed

Half power

41.5

Hz · F3

Xmax at

825

W RMS · no filter

With 25 Hz subsonic

827

W RMS · +0%

Amplifier

500

W RMS recommended

This enclosure holds 0.40 cu ft net per chamber. In it the Stereo Integrity BM-11 runs a system Qtc of 1.43 with half power at 41.5 Hz, and the cone reaches its 13.0 mm travel limit at 825 W, above the driver’s 500 W thermal rating, so heat stops you before travel does. A 25 Hz subsonic filter adds little here: 827 W against 825 W, 0 percent. The box already resonates at 59 Hz, so its own rolloff has removed most of what the filter would have stopped.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 35.9

BM-11 · EBP 35.9

EBP under 50 means a motor that wants a sealed load. The BM-11 sits at 35.9, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

0.40 cu ft against a 22.4 L Vas.

α = Vas ÷ Vb = 1.98 · Fc = Fs√(α+1) = 59 Hz · Qtc = 1.43

BM-11 · Qtc 1.43, Fc 59 Hz, F3 41.5 Hz

The box lifts resonance from 34.1 Hz free-air to 59 Hz and half power lands at 41.5 Hz, anechoic, before any cabin gain. Three sources disagree on this driver's total Q: Stereo Integrity publish 0.73, loudspeakerdatabase carries 0.83 and a ResoNix Klippel measurement gives 0.85. The curves here use 0.83. The alignment is under-damped on all three, so the disagreement moves the decimal and not the character.

03The 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 13.0 mm, and in this alignment a subsonic filter barely moves it.

P_Xmax = 825 W unfiltered → 827 W with a 25 Hz subsonic

BM-11 · 825 W, no filterBM-11 · 827 W with subsonic at 25 Hz, 24 dB/octXmax 13.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 13.0 mm. Unfiltered that is 825 W, reached first at 51 Hz. It sits above the 500 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct, and they sit almost on top of the solid ones: 827 W against 825 W. At 59 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.

Param	Value	Unit	Note
Fs	34.10	Hz	free-air resonance
Qts	0.830		BM-11
Vas	22.40	L	equivalent compliance
Sd	445.0	cm²	effective piston area
Xmax	13	mm	one-way linear travel
Pe	500	W	continuous RMS
SPL	81.6	dB	1 W / 1 m, derived from T/S

Driver parameters as published by loudspeakerdatabase.com. Curves computed against this enclosure’s actual net airspace.

Installer's take

Read the alignment first. 0.40 cubic feet net puts the BM-11 at Qtc 1.432 with resonance at 58.8 Hz and half power at 41.5 Hz anechoic.

This is a peaked box, not a flat one, and that is the driver rather than the cabinet. The BM-11's Qts is high enough that no small sealed enclosure gets it under 1.2. What you get in exchange is 41.5 Hz out of a cabinet only 9.81 inches deep at the base.

Stereo Integrity publish a Qts of 0.73 for the BM-11, loudspeakerdatabase carries 0.83, and a ResoNix Klippel measurement gives 0.85. We compute from 0.83, the self-consistent set and the middle of the three. The alignment is under-damped on all three readings, Qtc 1.26 to 1.47, so the disagreement changes the decimal and not the character.

On impedance: The BM-11 is a dual 2 ohm, so one driver is 4 ohms in series or 1 ohm in parallel.

Measure the base depth. This cabinet is 9.81 inches deep at the trunk floor, 4.71 at the top, and 16.74 wide.

Questions

Will this enclosure fit the BM-11 exactly?

Yes. The baffle is CNC cut to 10.00 in for the BM-11's cutout and the cabinet clears its 3.071 in mounting depth. Threaded inserts are pressed in at every mounting location.

Why 0.40 cubic feet net?

It puts the BM-11 at Qtc 1.432 with fc 58.8 Hz and F3 41.5 Hz anechoic. The BM-11 is under-damped in any small sealed box; this volume balances cabinet size against control.

What amplifier power should I run, and what impedance?

The BM-11 is rated 500 watts RMS, so 500 across the driver. The BM-11 is a dual 2 ohm, so one driver is 4 ohms in series or 1 ohm in parallel. Aim for roughly 350 to 500 watts at the final wired impedance.

How does a wedge enclosure improve the sound in a trunk installation?

The angled seat-side face matches the roughly 20 degree lean of a factory rear seat, so the cabinet sits flat against it instead of leaving a wasted triangle. The vertical trunk-lid-side face carries the driver, firing rearward into the trunk cavity.

Why is the front baffle double-layered?

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A subwoofer pushes as hard against its mounting surface as it does against the air, and a single 3/4 inch panel flexes under that load.

What is the expected low-frequency extension?

Anechoic F3 is 41.5 Hz at Qtc 1.432. The rolloff is peaked rather than flat, with a rise around 59 Hz. These figures exclude cabin gain, which in most vehicles adds real output below 40 Hz.

Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining and the quantity is chosen so it does not change the acoustic volume. Do not add more.

Is the driver included?

No. This is an enclosure only. You receive the cabinet finished in plush black carpet, with threaded inserts at the driver position, stainless machine screws, one side-mounted pre-wired terminal cup and the polyfill lining already installed.

Other Performance Optimized models

Stereo Integrity BM-11 Dual 11" Sealed
Stereo Integrity BM-11 Single 11" Sealed
Stereo Integrity BM-11 Single 11" Ported
Stereo Integrity BM-11 Triple 11" Sealed