Proline X PO 12-P W T0 ported wedge, front baffle with gloss black insert and pre-wired leads, 30 by 15.5 inches.Proline X PO 12-P W T0 ported wedge, side profile with recessed terminal cup, 15.26 inch base, 15.5 inches tall.

Performance Optimized · Datasheet

Performance Optimized Wedge Ported 12" Enclosure | Rockford Fosgate T0D412 Single 12" Ported enclosure

Net volume
1.59 Cubic Feet
Tuning
33.5 Hz
Max mounting depth
6.875 Inches (Rockford Fosgate Spec)
Cutout
11.250 Inches (Rockford Fosgate Spec)
External dimensions
30.00 Inches W × 15.50 Inches H × 9.62 Inches / 15.27 Inches D
Front baffle
Vertical Baffle - Driver Fires Rearward Into The Trunk
Buy at Audio Intensity
  • Alignment: 1.59 cu ft net vented at 33.5 Hz. F3 30.2 Hz anechoic, 3.43 dB passband ripple
  • Driver: Rockford Fosgate T0D412 D4, 700 W RMS, 14.8 mm Xmax, 26.00 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 15.50" H x 15.27" D at base tapering to 9.62" D at top, 21.4 sq in port, ships dry

Technical specifications

SeriesProline X Performance Optimized Wedge
Driver-Specific FitmentRockford Fosgate T0D412 D4 (Dual 4 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 Height15.50 Inches
Top Depth9.62 Inches
Base Depth15.27 Inches
Internal Volume (Gross)2.10 Cubic Feet
Internal Volume (Net After Displacement)1.59 Cubic Feet
Port TypeTriangular Slot | Bottom-Rear Corner | Straight, No Bend | Side Exit
Port GeometryIsosceles, 6.75 Inch Legs, 21.4 Square Inches, 24.86 Inches Long, Side Mouth
Port Tuning (Fb)33.5 Hz
Port MouthTriangle Through Side A, 1/2 In Roundover On All Three Edges, 33.3 Square Inches At The Face
Port ThroatOpen Far End, 3.39 In Gap To Side B, 3/8 In Roundover On The Panel End
Port Air Velocity22.1 m/s In The Channel, 14.2 m/s At The Flared Mouth (17.0 m/s Chuff Threshold)
Predicted F330.2 Hz (Anechoic)
Passband Ripple3.43 dB (Anechoic)
Subsonic Filter26 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs26.00 Hz
Driver Qts0.530
Driver Qes / Qms0.580 / 6.000
Driver Vas55.100 Liters / 1.946 Cubic Feet
Driver Sd548.0 Square Centimeters
Driver Re6.2 Ohm
Driver Xmax15mm (One-Way)
Driver Displacement0.11 Cubic Feet (Published by Rockford Fosgate)
Driver Sensitivity84.1 dB
Driver Power Handling700 Watts RMS
Driver Overall Diameter12.840 Inches (Rockford Fosgate Spec)
Mounting Depth Required6.875 Inches (Rockford Fosgate Spec)
Cutout Diameter11.250 Inches (Rockford Fosgate 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 4 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 Power489-700 Watts RMS (Rockford Fosgate Rated: 700W RMS)
Carpet FinishPlush Black
Weight52 lb
Bundle OptionsEnclosure Only (Bring Your Own Rockford Fosgate T0D412)
Warranty1-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA

Performance in this enclosure

Net airspace
1.59
cu ft
Tuning
33.5
Hz · Fb
Half power
30.2
Hz · F3, anechoic
Xmax at
2355
W RMS · 26 Hz subsonic
With NO filter
382
W RMS · unfiltered
Port
14.2
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 = 44.8
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EBP 44.8
Rockford Fosgate T0D412 · EBP 44.8
Under 50 the raw number leans sealed. The Rockford Fosgate T0D412 reads 44.8, 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

1.59 cu ft net against a 55.1 L Vas, vented at 33.5 Hz.

Fb = 33.5 Hz  ·  F3 = 30.2 Hz  ·  passband ripple 3.43 dB
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB −3 dB Fb 33.5
Rockford Fosgate T0D412 · Fb 33.5 Hz, F3 30.2 Hz
Anechoic, before any cabin gain, with the 26 Hz subsonic filter already applied. The vent takes over below 34 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, 1.59 cu ft net vented at 33.5 Hz, against Rockford Fosgate's recommended sealed box, 1.25 cu ft.

Ported Fb 33.5 Hz  ·  the 1.25 cu ft sealed box runs Qtc 0.85, Fc 42 Hz
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB +4.8 dB at 41 Hz
Ported · this cabinet, 1.59 cu ft, Fb 33.5 HzRockford Fosgate's recommended sealed, 1.25 cu ft net, Qtc 0.85
Shaded blue is where the ported alignment is louder for the same power, orange where the sealed one is. The sealed curve is Rockford Fosgate's recommended sealed box, 1.25 cu ft, 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 4.8 dB at its widest and 3.4 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 2.7 dB spread, the 1.25 cu ft sealed box 2.5 dB
20 30 50 70 100 150 200 +6 +0 −6 −12 −18 −24 FREQUENCY · Hz LEVEL · dB +4.8 dB at 41 Hz
Ported, in-car · 2.7 dB spreadRockford Fosgate's recommended sealed, 1.25 cu ft net, in-car · 2.5 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 2.7 dB of spread against 2.5 dB for Rockford Fosgate's recommended sealed box, 1.25 cu ft. The sealed curve is flatter on paper; the ported one trades that for output. Note where the curves cross. Below about 23 Hz the sealed alignment becomes the louder of the two and stays louder all the way down, by up to 1.8 dB: a sealed box rolls off gently into the subsonic region where a vented one falls away steeply once it is below tuning and the vent stops contributing. If the content you are chasing lives below 23 Hz, a sealed alignment reaches further down than this one does. 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 Rockford Fosgate's published 14.8 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

PXmax = 2355 W with a 26 Hz subsonic  ·  382 W with none  →  the filter is worth 6.2×
20 30 50 70 100 150 200 0 4 8 12 16 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 14.8 mm 2355 W reaches Xmax here
2355 W · subsonic at 26 Hz, 24 dB/oct382 W · no subsonic filterXmax 14.8 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 14.8 mm. With a 26 Hz subsonic that takes 2355 W, reached first at 24 Hz. Take the filter away and the same cabinet reaches 14.8 mm on 382 W — the filter is worth 6.2× 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 382 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 — Rockford Fosgate rate this one at 700 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 700 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.

Installer's take

700 watts on a 26 Hz motor, and reaching low with this much motor is not free: F3 30.2 Hz on 3.43 dB of ripple, 2.66 dB in the car at 33.5 Hz tuning. The port carries the load at 22.1 metres per second against a 22.7 limit, the fastest channel of the Rockford wedges. Inside the rule with little spare.

Run the 26 Hz filter and hold the amplifier to the rating; at 700 watts the cone uses 8.1 of its 14.8 mm. A 6.75 inch leg needs 9.57 inches of top depth to clear the 6.88 inch motor, so the cabinet is 9.62 at the top and 15.27 at the base.

Questions

Why is this enclosure tuned to 33.5 Hz?

Reaching low with this much motor is not free: the anechoic F3 is 30.2 Hz on 3.43 dB of ripple, and the in-car spread is 2.66 dB across 25 to 60 Hz at 33.5 Hz tuning. The port takes 24.86 of the 25.21 inches available and runs at 22.1 metres per second in the channel against a 22.7 limit, 14.2 at the rounded 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 2.7 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 15.27 inches deep at the base and 9.62 at the top, 30.00 wide and 16 tall.

Do I need a subsonic filter?

Yes, at 26 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 Rockford Fosgate T0D412 at 55 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?

Rockford Fosgate rate the T0D412 at 700 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 55 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?

Below about 23 Hz, yes. The maker's recommended sealed box is louder down there by up to 1.8 dB, because a sealed box rolls off gently where a vented one falls away steeply under tuning. Above that this alignment is the louder of the two for the same power. The Performance Graphs tab plots this cabinet against Rockford Fosgate's recommended sealed box, 1.25 cu ft.

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 3.39 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 24.86 inches of path and 21.4 square inches of channel running at 22.1 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 33.3 square inches and the air leaves it at 14.2 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 24.86 inches for 33.5 Hz. Stuff it and you move the tuning without shortening the port.

Is the T0D412 included?

No. This is an enclosure only, cut for the Rockford Fosgate T0D412 specifically: the 11.250 inch cutout, the 6.875 inch mounting depth allowance and the 1.59 cubic foot alignment all come from Rockford Fosgate's published parameters. It fits both coil versions; the alignment published here is the D4. Bring your own driver.

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