A black fabric-covered subwoofer enclosure box with a circular wood-grain front opening, showing internal wiring and a 1.0 ft net, on a solid white background.

Performance Optimized · Datasheet

Performance Optimized Sealed 12" Enclosure | Stereo Integrity SQL-12 Single 12" Sealed enclosure

Net volume
1.0 Cubic Feet
Max mounting depth
13 Inches
Cutout
11.33 Inches
External dimensions
20 Inches W × 15 Inches H × 13.625 Inches D
Front baffle
Double Baffle (1.5" Total Thickness at Mounting Face)
Buy at Audio Intensity
  • Best For: Single SI SQL 12 High-Power SQ+SPL Builds
  • Net Volume: 1.0 cu ft Sealed (SI Maximum Specification)
  • Driver Match: Stereo Integrity SQL 12 Series 2 (D2 or D4)
  • Construction: V-Groove/Dado | Double Baffle | Threaded Inserts

Technical specifications

Enclosure TypeSealed
Baffle ConfigurationDouble Baffle (1.5" Total Thickness at Mounting Face)
Driver-Specific FitmentStereo Integrity SQL 12 Series 2 (Dual 2Ω or Dual 4Ω)
Internal Volume (Net)1.0 Cubic Feet
MaterialLangboard Elite 3/4" MDF (Doubled at Mounting Face)
JoineryV-Groove and Dado (CNC-Cut)
ConstructionShopSabre CNC
External Width20 Inches
External Height15 Inches
External Depth13.625 Inches
Mounting Hole Diameter11.33 Inches
Max Mounting Depth13 Inches
Mounting Hardware8/32 Threaded Inserts Into Double Baffle | Stainless Steel Screws Included
Terminal CupProline X ABS/Carbon Fiber Composite | 12g OFC Pre-Wired
DampingPolyfill Pre-Installed
Recommended Power750-1000 Watts RMS (1000W RMS Driver Rating)
Carpet FinishDark Gray Trunkliner (Standard) or Plush Black
Acrylic InsertBlack, Blue, Red, White, or None
Bundle OptionsBox Only | Add a Paper Cone Driver | Add a Carbon Fiber Driver
Warranty1-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA

Performance in this enclosure

Net airspace
1.00
cu ft per chamber
System Qtc
0.76
sealed
Half power
42.6
Hz · F3
Xmax at
2964
W RMS · no filter
With 25 Hz subsonic
3758
W RMS · +27%
Amplifier
1000
W RMS recommended
This enclosure holds 1.00 cu ft net per chamber. In it the Stereo Integrity SQL-12 Series 2 runs a system Qtc of 0.76 with half power at 42.6 Hz, and the cone reaches its 28.0 mm travel limit at 2964 W, above the driver’s 1000 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 3758 W — +794 W, or 27 percent more power for the same 28.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 55.0
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D2/D4 55.0
D2/D4 · EBP 55.0
At 55.0 the SQL-12 Series 2 sits in the transition band, not the sealed band. That is not a mismatch: a transition motor works in either alignment, and sealed buys a smaller box and a gentler roll-off at the cost of some low-end output. Stage 02 shows what this airspace actually does with it.

02What the box does to it

1.00 cu ft against a 22.5 L Vas.

α = Vas ÷ Vb = 0.79  ·  Fc = Fs√(α+1) = 46 Hz  ·  Qtc = 0.76
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D2/D4 · Qtc 0.76, Fc 46 Hz, F3 42.6 Hz
The box lifts resonance from 34.1 Hz free-air to 46 Hz and half power lands at 42.6 Hz, anechoic, before any cabin gain.

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 28.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 2964 W unfiltered  →  3758 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 8 16 24 32 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 28.0 mm 2964 W reaches Xmax here
D2/D4 · 2964 W, no filterD2/D4 · 3758 W with subsonic at 25 Hz, 24 dB/octXmax 28.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 28.0 mm. Unfiltered that is 2964 W, reached first at 20 Hz. It sits above the 1000 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: stopping the cone wasting travel below the passband lets it take 3758 W before hitting the same 28.0 mm. That is 27 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs34.10Hzfree-air resonance
Qts0.570D2/D4
Vas22.50Lequivalent compliance
Sd532.3cm²effective piston area
Xmax28mmone-way linear travel
Pe1000Wcontinuous RMS
SPL83.4dB1 W / 1 m, derived from T/S

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

Installer's take

A single SQL 12 in a properly built cabinet is more system than most people think. Nick Sowa engineered the SQL Series specifically to deliver deep low-end extension and high output in small sealed cabinets, and the SQL 12 in a 1.0 cubic foot sealed box will genuinely surprise anyone who thinks you need dual 12s to have a serious system. F3 points drop into single-digit territory in this cabinet. Output stays clean at real listening volumes. And the single-driver footprint fits behind seats and against trunk walls in a way a dual configuration can't. The 1.0 cubic foot volume is SI's maximum specified sealed volume for the SQL 12. That's important. Below 0.65 cubic feet the driver overdamps and loses its low-end signature. Above 1.0 you're outside SI's engineered range and losing transient control. 1.0 lands the SQL right at the peak of its extension capability while staying inside the driver's operating window. This is the volume where the SQL 12 delivers on the marketing promise. The double baffle is not decorative on this build. A single 3/4 inch baffle will flex under a 1000 watt SQL 12 at full excursion. You can measure it, and you can hear it as coloration and reduced efficiency. Doubling to 1.5 inches at the mounting position eliminates flex almost entirely. The threaded inserts get pressed into the full doubled stock, giving full-depth thread engagement so the driver stays locked to the baffle no matter how hard you drive it. This is standard practice on serious high-power sealed builds, and it's the reason this box will still be tight and solid five years from now with a 1000-watt daily driver installed. V-groove and dado joinery through the rest of the cabinet is the other reason this box holds together at power. Every joint is mechanically interlocked, not just glued. Panel-to-panel bonds have maximum glue surface from the V-groove cuts. The baffle drops into a dado in the side walls. The box is designed to be treated as a single rigid structure, not a collection of panels waiting to separate under load. Wiring is straightforward. Dual 2-ohm gets you 1 ohm parallel or 4 ohms series. Dual 4-ohm gets you 2 ohms parallel or 8 ohms series. The 1000 watt RMS rating means a clean 750 to 1000 watt monoblock at your chosen impedance is the target. At this power level, don't cut corners on the amp, regulated power supply, honest RMS ratings, low THD. The SQL 12 will show up a cheap amplifier immediately. Paper cone versus carbon fiber is a real decision. Paper is 80 dollars cheaper and sounds cleaner on acoustic music. Carbon fiber stays more pistonic on high-impact material. Both are legitimate picks. If you listen to a lot of rock, jazz, or vocal-heavy material, paper is arguably the better tonal choice. If your playlist leans electronic or hip-hop and you want maximum impact, carbon fiber is worth the upcharge. For a single 12 sealed system where you're not compromising on either extension or power capability, this is the box the SQL 12 was designed to live in. -Scott

Questions

What size enclosure does the Stereo Integrity SQL 12 need?

The Stereo Integrity SQL 12 Series 2 performs best in a sealed enclosure between 0.65 and 1.0 cubic feet. The Audio Intensity Performance Optimized Sealed 12 for SI SQL 12 delivers 1.0 cubic feet net internal volume, the maximum of Stereo Integrity's specified sealed range, where the SQL 12's deep low-end extension fully develops with F3 points in single-digit territory.

What are the dimensions of the Performance Optimized Sealed 12 enclosure for the SI SQL 12?

The Performance Optimized Sealed 12 enclosure for the Stereo Integrity SQL 12 measures 20" wide x 15" tall x 13.625" deep externally. Net internal volume is 1.0 cubic foot, with a maximum mounting depth of 13 inches behind the doubled baffle.

Does the Performance Optimized Sealed 12 for SI SQL 12 use a double baffle?

Yes. The Performance Optimized Sealed 12 for Stereo Integrity SQL 12 uses a doubled 1.5-inch baffle at the mounting face, two layers of 3/4-inch Langboard Elite MDF bonded together. The 8/32 threaded inserts are pressed into the full 1.5-inch doubled stock for maximum thread engagement, preventing baffle flex and mounting screw pullout at the 1000-watt RMS power level the SQL 12 delivers. The cabinet uses V-groove and dado joinery throughout.

How much power can the Stereo Integrity SQL 12 handle?

The Stereo Integrity SQL 12 Series 2 handles 1000 watts RMS. For best results in the Performance Optimized Sealed 12 enclosure, pair the SQL 12 with a clean, regulated monoblock amplifier delivering 750 to 1000 watts RMS at your chosen impedance. At this power level, amplifier quality matters more than headline peak numbers, look for regulated power supply, low THD, and honest RMS ratings.

What impedance and cone options are available for the Stereo Integrity SQL 12?

The Stereo Integrity SQL 12 Series 2 is available in two dual voice coil impedance configurations (Dual 2-ohm or Dual 4-ohm) and two dust cap options (Paper or Carbon Fiber). A Dual 2-ohm SQL 12 wired in parallel presents 1 ohm, in series presents 4 ohms. A Dual 4-ohm SQL 12 wired in parallel presents 2 ohms, in series presents 8 ohms. Paper cones deliver cleaner acoustic music reproduction; carbon fiber stays more pistonic on high-impact electronic material.

What is the mounting depth of the Stereo Integrity SQL 12?

The Stereo Integrity SQL 12 Series 2 has a 7-inch mounting depth with an 11.33-inch cutout diameter and 12.91-inch outer diameter. The Performance Optimized Sealed 12 enclosure has a 13-inch maximum mounting depth, providing comfortable internal clearance for the SQL 12's motor structure and adequate magnet ventilation inside the 13.625" deep cabinet.

What mounting hardware does the Performance Optimized Sealed 12 for SI SQL 12 include?

The Performance Optimized Sealed 12 for Stereo Integrity SQL 12 includes 8/32 threaded inserts pressed into the doubled 1.5-inch baffle backside and stainless steel mounting screws sized for the Stereo Integrity SQL 12. The enclosure also includes a Proline X ABS/carbon fiber composite terminal cup pre-wired with 12-gauge OFC and stainless steel input hardware accepting spade or banana terminations.

Where is the Performance Optimized Sealed 12 for SI SQL 12 manufactured?

The Performance Optimized Sealed 12 for Stereo Integrity SQL 12 is manufactured in Tullahoma, Tennessee, USA. Each enclosure is CNC-cut from Langboard Elite 3/4" MDF on ShopSabre routers and hand-assembled at Audio Intensity's Tennessee facility. Build time is 2 to 5 business days from order placement.

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