Performance Optimized · Datasheet

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

Net volume
0.97 Cubic Feet
Tuning
36.5 Hz
Max mounting depth
3.071 Inches (Stereo Integrity Spec)
Cutout
10.000 Inches (Stereo Integrity Spec)
External dimensions
30.00 Inches W × 14.50 Inches H × 6.50 Inches / 11.78 Inches D
Front baffle
Vertical Baffle - Driver Fires Rearward Into The Trunk
Buy at Audio Intensity
  • Alignment: 0.97 cu ft net vented at 36.5 Hz. F3 32.4 Hz anechoic, 4.50 dB passband ripple
  • Driver: Stereo Integrity BM-11, 500 W RMS, 13.0 mm Xmax, 34.10 Hz Fs
  • Build: Rear-firing wedge, 20 degree rear rake, V-groove and dado joinery, triangular side-exit slot port with a 1/2" rounded mouth, double 1.5" baffle, side-mounted terminal cup
  • Cabinet: 30.00" W x 14.50" H x 11.78" D at base tapering to 6.50" D at top, 14.2 sq in port, ships dry

Technical specifications

SeriesProline X Performance Optimized Wedge
Driver-Specific FitmentStereo Integrity BM-11 (Dual 2 Ohm)
Enclosure TypePorted | Rear-Firing Trunk Wedge
Baffle ConfigurationVertical Baffle - Driver Fires Rearward Into The Trunk
Wedge Angle20 Degrees On The Rear (Seat-Side) Panel
External Width30.00 Inches
External Height14.50 Inches
Top Depth6.50 Inches
Base Depth11.78 Inches
Internal Volume (Gross)1.27 Cubic Feet
Internal Volume (Net After Displacement)0.97 Cubic Feet
Port TypeTriangular Slot | Bottom-Rear Corner | Straight, No Bend | Side Exit
Port GeometryIsosceles, 5.50 Inch Legs, 14.2 Square Inches, 23.48 Inches Long, Side Mouth
Port Tuning (Fb)36.5 Hz
Port MouthTriangle Through Side A, 1/2 In Roundover On All Three Edges, 24.2 Square Inches At The Face
Port ThroatOpen Far End, 4.77 In Gap To Side B, 3/8 In Roundover On The Panel End
Port Air Velocity20.8 m/s In The Channel, 12.2 m/s At The Flared Mouth (17.0 m/s Chuff Threshold)
Predicted F332.4 Hz (Anechoic)
Passband Ripple4.50 dB (Anechoic)
Subsonic Filter29 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs34.10 Hz
Driver Qts0.830
Driver Qes / Qms0.950 / 6.690
Driver Vas22.400 Liters / 0.791 Cubic Feet
Driver Sd445.0 Square Centimeters
Driver Mms271.00 g
Driver BL14.60
Driver Re3.5 Ohm
Driver Xmax13mm (One-Way at 70% BL)
Excursion Design BasisDerated To 11.0mm For Alignment - Stereo Integrity Publishes At 70% BL
Driver Displacement0.03 Cubic Feet (Published by Stereo Integrity)
Driver Sensitivity82.5 dB
Driver Power Handling500 Watts RMS
Driver Overall Diameter11.142 Inches (Stereo Integrity Spec)
Mounting Depth Required3.071 Inches (Stereo Integrity Spec)
Cutout Diameter10.000 Inches (Stereo Integrity Spec)
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC / Two Windowed C Braces At The Third Points, Seated On The Port Panel
JoineryV-Groove and Dado (CNC-Cut)
Front Baffle ConstructionDouble-Layer 1.5" MDF | Cosmetic Front Layer Routed For The Acrylic Insert
Mounting HardwareThreaded Inserts At Every Mounting Location | Stainless Steel Machine Screws Included
Voice Coil ConfigurationDual 2 Ohm
Terminal CupProline X ABS/Carbon Fiber Composite | Side Mounted, Opposite The Port | 12g OFC Pre-Wired
DampingNone - Ships Dry. Polyfill Detunes A Ported Enclosure
Recommended Power350-500 Watts RMS (Stereo Integrity Rated: 500W RMS)
Carpet FinishPlush Black
Weight44 lb
Bundle OptionsEnclosure Only (Bring Your Own Stereo Integrity BM-11)
Warranty1-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA

Performance in this enclosure

Net airspace
0.97
cu ft
Tuning
36.5
Hz · Fb
Half power
32.4
Hz · F3, anechoic
Xmax at
1900
W RMS · 29 Hz subsonic
With NO filter
275
W RMS · unfiltered
Port
12.2
m/s at the mouth

01Is this driver right for a ported box?

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

EBP = Fs ÷ Qes = 35.9
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EBP 35.9
Stereo Integrity BM-11 · EBP 35.9
Under 50 the raw number leans sealed. The Stereo Integrity BM-11 reads 35.9, 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

0.97 cu ft net against a 22.4 L Vas, vented at 36.5 Hz.

Fb = 36.5 Hz  ·  F3 = 32.4 Hz  ·  passband ripple 4.50 dB
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB −3 dB Fb 36.5
Stereo Integrity BM-11 · Fb 36.5 Hz, F3 32.4 Hz
Anechoic, before any cabin gain, with the 29 Hz subsonic filter already applied. The vent takes over below 36 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, 0.97 cu ft net vented at 36.5 Hz, against the 0.40 cu ft sealed wedge we build for this driver (PO 11-S W BM11).

Ported Fb 36.5 Hz  ·  the 0.40 cu ft sealed box runs Qtc 1.43, Fc 59 Hz
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB +7.4 dB at 29 Hz
Ported · this cabinet, 0.97 cu ft, Fb 36.5 HzSealed wedge we build, 0.40 cu ft, Qtc 1.43
Shaded blue is where the ported alignment is louder for the same power, orange where the sealed one is. The sealed curve is the 0.40 cu ft sealed wedge we build for this driver (PO 11-S W BM11), 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 7.4 dB at its widest and 6.3 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 3.0 dB spread, the 0.40 cu ft sealed box 6.7 dB
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB +7.4 dB at 29 Hz
Ported, in-car · 3.0 dB spreadSealed wedge we build, 0.40 cu ft, in-car · 6.7 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 3.0 dB of spread against 6.7 dB for the 0.40 cu ft sealed wedge we build for this driver (PO 11-S W BM11). 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 Stereo Integrity's published 13.0 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

PXmax = 1900 W with a 29 Hz subsonic  ·  275 W with none  →  the filter is worth 6.9×
20 30 50 70 100 150 200 0 4 8 12 16 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 13.0 mm design limit 11.0 mm · 70% BL derated 1900 W reaches Xmax here
1900 W · subsonic at 29 Hz, 24 dB/oct275 W · no subsonic filterXmax 13.0 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 13.0 mm. With a 29 Hz subsonic that takes 1900 W, reached first at 26 Hz. Take the filter away and the same cabinet reaches 13.0 mm on 275 W — the filter is worth 6.9× 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 275 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 — Stereo Integrity rate this one at 500 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 500 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. The dashed line at 11.0 mm is the figure the cabinet was actually designed against: Stereo Integrity publish this Xmax on a 70% BL basis, and we derate it before sizing the port so the alignment carries margin against an optimistic spec rather than sitting right on it.

Installer's take

The BM-11 is an 11 inch on a 3.07 inch mounting depth, and its Qts is published three ways: 0.73 by SI, 0.83 by loudspeakerdatabase, 0.85 by a ResoNix Klippel run. I compute from 0.83. In SI's 0.40 cubic foot sealed box those readings give a Qtc between 1.26 and 1.47, a peaky sealed alignment, and venting is how you get reach out of this motor without the peak. At 36.5 Hz the wedge holds ripple to 4.50 dB, exactly the line this range allows, for an F3 of 32.4 Hz and 2.83 dB in the car.

Because the ripple sits on the line, this is not a cabinet to push past its numbers. Xmax is quoted at 70 percent BL and derated from 13 to 11.0 mm; the cone uses 6.7 of that at 500 watts with the subsonic filter set. It has the shallowest top in the ported line, 6.50 inches, with 11.78 at the base on a 14.5 inch height, and 3.28 inches of floor stay clear in front of the port panel, just over the 3 inch rule.

Questions

Why is this enclosure tuned to 36.5 Hz?

A high Qts driver vented wants the tuning near its resonance and a firm hand on the box: 36.5 Hz holds the anechoic ripple to 4.50 dB, right at the line this range allows, for an F3 of 32.4 Hz and 2.83 dB of in-car spread across 25 to 60 Hz. Stereo Integrity publish sealed volumes only for the BM-11 (0.35 to 0.70 cubic feet); their 0.40 gives a Qtc near 1.4, and vented is the way to get reach out of this motor without that peak. The port takes 23.48 of the 25.77 inches available and runs at 20.8 metres per second in the channel against a 21.3 limit, 12.2 at the mouth. Tuning is chosen for in-car response rather than an anechoic curve: a vehicle adds roughly 12 dB per octave below about 45 Hz. In this cabinet that lands at 3.0 dB of in-car spread across 25 to 60 Hz.

Why the 20 degree wedge, and why rear-firing?

The raked face is the seat side. A factory rear seat back leans about 20 degrees off vertical, so the cabinet sits flat against it and uses floor a square box wastes. The baffle stays vertical and fires rearward into the trunk, which acts as the acoustic extension into the cabin. This one is 11.78 inches deep at the base and 6.50 at the top, 30.00 wide and 14 tall.

Do I need a subsonic filter?

Yes, at 29 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 Stereo Integrity BM-11 at 60 percent of its usable travel at full rated power; without it there is no meaningful number to quote.

How much power can I run, and at what impedance?

Stereo Integrity rate the BM-11 at 500 W RMS and that is the thermal ceiling. The Performance Graphs tab shows the mechanical limit, the power at which the cone reaches the end of its travel in this cabinet: here the cone sits at 60 percent of usable travel at the rating, so heat is what stops you, not travel. A D2 coil is 4 ohms in series or 1 ohm in parallel; run series unless the amplifier is rated for 1 ohm. A D4 is 8 series or 2 parallel.

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. The Performance Graphs tab plots this cabinet against the 0.40 cu ft sealed wedge we build for this driver (PO 11-S W BM11).

How does the side port work?

It is a triangular slot in the bottom-rear corner: the floor and the raked back wall are two sides, one bevelled panel is the third. It runs across the cabinet, opens into the box through a 4.77 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 23.48 inches of path and 14.2 square inches of channel running at 20.8 metres per second, 54 percent of its turbulence limit. The three mouth edges are rounded over at 1/2 inch, so the opening at the face is 24.2 square inches and the air leaves it at 12.2 metres per second against the 17.0 threshold where a slot port starts to chuff; the panel's throat end is rounded at 3/8 inch for the same reason. The terminal cup is on the other side.

Does this enclosure ship with polyfill?

No, and do not add any. Every sealed Proline X enclosure ships with polyfill; a ported one must not, because damping changes the effective volume the port is tuned against. The port here is cut to 23.48 inches for 36.5 Hz. Stuff it and you move the tuning without shortening the port.

Is the BM-11 included?

No. This is an enclosure only, cut for the Stereo Integrity BM-11 specifically: the 10.000 inch cutout, the 3.071 inch mounting depth allowance and the 0.97 cubic foot alignment all come from Stereo Integrity's published parameters. It fits both coil versions; the alignment published here is the . Bring your own driver.

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