

Performance Optimized · Datasheet
Performance Optimized Down Fire Wide Sealed Dual 12" Enclosure Morel Ultimo PowerSlim PS124D · Dual 12" Sealed enclosure
- Net volume
- 0.807 cu ft after displacement
- Max mounting depth
- 3.386 in
- External dimensions
- 41 in W × 8.75 in in the down fire position H × 14 in D
- Front baffle
- 1.5 in double baffle, outer layer machined as a flush recess
- Alignment: 0.807 cu ft net per chamber. Qtc 1.067, Fc 42.7 Hz, F3 32.7 Hz
- Down Fire Wide: 41"W x 14"D x 8.75"H in down fire position, excludes the 1.75" standoffs (installed height 10.5"). Stands lower than the standard 30 x 15 at 10.75"
- Height set by: airspace; 4.61" of clearance above the motor
- Chambers: Two fully separate sealed chambers, 3/4" MDF full divider, one shared side-mounted terminal cup
- Driver: Pair of Morel PS124D (DVC 4 ohm), 700W RMS each / 1400W combined, 24 Hz Fs, 11mm Xmax each way
- Build: Langboard Elite MDF, V-groove and dado, 1.5" double baffle with flush outer recess, full divider, 12g OFC side-mounted terminal cup
Spec of record
Technical specifications
| Series | Proline X Performance Optimized Down Fire Wide |
|---|---|
| Compatible Driver | Morel Ultimo PowerSlim PS124D (DVC 4 ohm), pair required. Direct fit |
| Enclosure Type | Sealed, dual driver, down fire, floor coupled |
| Intended Fitment | Long, low spaces where height or depth is the limit and 41 in of run is available |
| Firing Direction | Down firing. Feet ship uninstalled, so front or up firing is also possible |
| Chamber Configuration | Two fully separate chambers, full divider, single shared side-mounted terminal cup |
| External Width | 41 in |
| External Depth | 14 in |
| External Height | 8.75 in in the down fire position, excludes standoffs |
| Installed Height | 10.5 in including the 1.75 in standoffs |
| Dimension Reference | All external dimensions measured in down fire position |
| Standard 30 x 15 Version | 10.75 in tall, 0.80 cu ft net per chamber |
| Internal Volume, Gross | 1.81 cu ft total |
| Per-Chamber Net Volume | 0.807 cu ft after displacement |
| Total Net Volume | 1.615 cu ft |
| Height Set By | Airspace; 4.61 in clearance above the motor |
| Alignment (per chamber) | Qtc 1.067, Fc 42.7 Hz, F3 32.7 Hz anechoic |
| Woofer Opening | 10.6 in each |
| Mounting Depth Required | 3.386 in |
| Frame Outer Diameter | 12.008 in |
| Driver Displacement | 0.08 cu ft, estimated; Morel publishes no displacement figure, so the 12 inch rule of thumb is used |
| Driver Fs | 24 Hz |
| Driver Qts | 0.6 |
| Driver Vas | 49.4 Liters Each |
| Driver Xmax | ±11mm |
| Cone Area | 452.4 cm² Each / 904.8 cm² Total |
| Power Handling | 700 Watts RMS Each / 1400 Watts RMS Combined |
| Driver Cone | Flat Honeycomb Hexatech Aluminium |
| Driver Voice Coil | 129.5mm / 5.1" | 4 Layers Carbon | Aluminium Former |
| Driver Motor | Double Magnet EVC |
| Awards | EISA Best In-Car Subwoofer 2023-2024 (Ultimo PowerSlim Series) |
| Driver Mounting | 8/32 Threaded Inserts | Stainless Steel Machine Screws Included | 2 Sets |
| Voice Coil Configuration | Dual 4-Ohm Per Driver - Final Impedance Set At The Drivers |
| Recommended Power Per Driver | 350-700 Watts RMS (Morel Rated Range) |
| Material | Langboard Elite 3/4 in MDF |
| Joinery | V-groove and dado, CNC cut on ShopSabre routers |
| Front Baffle | 1.5 in double baffle, outer layer machined as a flush recess |
| Internal Bracing | Full-height 3/4 in bonded divider plus perimeter cross-brace |
| Corner Profile | Square (Down Fire series standard) |
| Terminal Cup | One Proline X ABS and carbon fiber composite, side mounted, pre-wired 12 gauge OFC to both driver positions |
| Standoffs | 1.75 in, included, shipped uninstalled |
| Damping | Polyfill installed as a light wall lining in each chamber |
| Carpet | Plush black |
| Bundle Options | Enclosure only (bring your own pair of Morel PS124D) |
| Warranty | 1 year limited (enclosure) |
| Built In | Tullahoma, Tennessee, USA |
Modelled response
Performance in this enclosure
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
0.807 cu ft against a 49.4 L Vas.
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 11.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 24.00 | Hz | free-air resonance |
| Qts | 0.600 | D4 | |
| Vas | 49.40 | L | equivalent compliance |
| Sd | 452.4 | cm² | effective piston area |
| Xmax | 11 | mm | one-way linear travel |
| Pe | 700 | W | continuous RMS |
| SPL | 81.7 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by Morel Ultimo PowerSlim owner's manual, rev 24-12-23. Curves computed against this enclosure’s actual net airspace.
From the shop floor
Installer's take
Two PS124D in a box 8.75 inches tall instead of 10.75. Same 22.7 liters per driver Morel recommends, spread along 41 inches so the pair fits where the standard dual would not.
Height was solved to the airspace: 8.75 tall holds 0.807 net per chamber, against 0.80 in the standard box, and the motor clears the lid with 4.61 inches to spare. Same air, lower box.
Per chamber the alignment is Qtc 1.067 with F3 at 32.7 Hz. The 24 Hz free-air resonance and 49.4 liter Vas are conventional driver numbers in a shallow frame, and that is where the reach comes from.
Separate chambers as always. One side-mounted cup feeds both positions in parallel. Dual 4 ohm coils per driver: set impedance at the drivers, wire both identically, and target 350 to 700 watts RMS per driver.
Measure installed height, not cabinet height: 8.75 on its own, 10.5 with the 1.75 inch feet on. The standard 30 by 15 is still the pick if you do not have 41 inches of run.
Before you order
Questions
Why is this cabinet 41 inches wide instead of 30?
Because it trades length for depth and height. The standard Performance Optimized Down Fire platform is 30 wide by 15 deep; this one is 14 deep, 1 inch shallower, and 41 long. Spreading the airspace along 11 more inches lets the cabinet stand 8.75 inches tall instead of 10.75.
Fourteen inches of depth is the practical minimum, since a 12 inch frame needs about 13 inches of baffle. If your space is long and low rather than deep or tall, this is the shape that fits.
How does this compare to the standard 30 x 15 dual PS124D enclosure?
Same driver, different shape. The standard cabinet is 30 by 15 by 10.75 inches and holds 0.80 cubic feet net per chamber. This cabinet is 41 by 14 by 8.75 inches and holds 0.807 cubic feet net per chamber.
The airspace is effectively the same, so the driver behaves the same way in either. Choose the standard box when length is limited; choose this one when height or depth is the limit and you have 41 inches of run.
What alignment does each driver see in this cabinet?
Each chamber holds 0.807 cubic feet net, Morel's own 22.7 liter recommendation, and each PS124D lands at Qtc 1.067 with Fc at 42.7 Hz and a predicted F3 of 32.7 Hz, computed from Morel's published Fs 24 Hz, Qts 0.6 and Vas 49.4 liters.
Qts is 0.6, so Qtc cannot fall below that in any sealed box. The modest lift near the corner is the driver's intended character.
How is this enclosure wired, and how do I set my final impedance?
One side-mounted Proline X terminal cup with a single pair of posts, pre-wired in 12 gauge OFC to both driver positions in parallel. You do not wire the two chambers separately at the amplifier.
Each PS124D has dual 4 ohm voice coils, so the way you wire each driver's coils sets the load the amplifier sees. Wire both drivers identically. With 1400 watts RMS combined, confirm the load against your amplifier's minimum stable impedance before powering the system.
Where is the terminal cup located on a down fire enclosure?
Side mounted, and there is one cup serving both chambers rather than one per chamber. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup, whether standard, wedge or down fire, which keeps the connection accessible with both baffles facing the floor. The cup is our Proline X ABS and carbon fiber composite unit, recessed, with stainless hardware, copper ring terminals and pre-wired 12 gauge OFC to both driver positions in parallel.
Why are the corners square instead of radiused?
Down Fire cabinets are built with square corners as a series standard. The 3 inch top down corner radius used on other Proline X alignments does not apply here. A down fire box is a low, long platform that sits flat against a floor or cargo deck, and square corners maximize usable internal volume for a given footprint while keeping the cabinet stable on its mounting surface.
How is this enclosure built?
V-groove and dado joinery, CNC cut on ShopSabre routers from Langboard Elite MDF. Every panel joint is a machined interlocking groove that locks the panels before adhesive is applied, which keeps both chambers airtight under sustained pressure cycling. The front baffle is a 1.5 inch double layer, the outer layer machined as a flush recess around the 10.6 inch cutouts.
A full-height bonded 3/4 inch divider separates the chambers and ties the walls together across the 41 inch span, with perimeter cross-bracing and a light polyfill wall lining in each chamber. Do not add more fill; packing a sealed box makes it act larger and moves the alignment. Assembled and inspected in Tullahoma, Tennessee.
Are the Morel PS124D subwoofers included with this enclosure?
No. This listing is for the enclosure only. Bring your own pair of Morel Ultimo PowerSlim PS124D subwoofers. The cutouts and mounting depth are direct fit at both driver positions.
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