
Performance Optimized · Datasheet
Performance Optimized Wedge Ported 8" Enclosure | Rockford Fosgate P2D2-8 Single 8" Ported enclosure
- Net volume
- 0.92 Cubic Feet
- Tuning
- 35.5 Hz
- Max mounting depth
- 4.760 Inches (Rockford Fosgate Spec)
- Cutout
- 7.130 Inches (Rockford Fosgate Spec)
- External dimensions
- 29.00 Inches W × 11.75 Inches H × 8.62 Inches / 12.90 Inches D
- Front baffle
- Vertical Baffle - Driver Fires Rearward Into The Trunk
- Alignment: 0.92 cu ft net vented at 35.5 Hz. F3 30.3 Hz anechoic, 2.40 dB passband ripple
- Driver: Rockford Fosgate P2D2-8 D2, 250 W RMS, 7.8 mm Xmax, 39.60 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: 29.00" W x 11.75" H x 12.90" D at base tapering to 8.62" D at top, 13.0 sq in port, ships dry
Technical specifications
| Series | Proline X Performance Optimized Wedge |
|---|---|
| Driver-Specific Fitment | Rockford Fosgate P2D2-8 D2 (Dual 2 Ohm) |
| Enclosure Type | Ported | Rear-Firing Trunk Wedge |
| Baffle Configuration | Vertical Baffle - Driver Fires Rearward Into The Trunk |
| Wedge Angle | 20 Degrees On The Rear (Seat-Side) Panel |
| External Width | 29.00 Inches |
| External Height | 11.75 Inches |
| Top Depth | 8.62 Inches |
| Base Depth | 12.90 Inches |
| Internal Volume (Gross) | 1.22 Cubic Feet |
| Internal Volume (Net After Displacement) | 0.92 Cubic Feet |
| Port Type | Triangular Slot | Bottom-Rear Corner | Straight, No Bend | Side Exit |
| Port Geometry | Isosceles, 5.25 Inch Legs, 13.0 Square Inches, 23.92 Inches Long, Side Mouth |
| Port Tuning (Fb) | 35.5 Hz |
| Port Mouth | Triangle Through Side A, 1/2 In Roundover On All Three Edges, 22.5 Square Inches At The Face |
| Port Throat | Open Far End, 3.33 In Gap To Side B, 3/8 In Roundover On The Panel End |
| Port Air Velocity | 20.3 m/s In The Channel, 11.6 m/s At The Flared Mouth (17.0 m/s Chuff Threshold) |
| Predicted F3 | 30.3 Hz (Anechoic) |
| Passband Ripple | 2.40 dB (Anechoic) |
| Subsonic Filter | 28 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure |
| Driver Fs | 39.60 Hz |
| Driver Qts | 0.460 |
| Driver Qes / Qms | 0.510 / 5.400 |
| Driver Vas | 9.900 Liters / 0.350 Cubic Feet |
| Driver Sd | 221.0 Square Centimeters |
| Driver Re | 3.4 Ohm |
| Driver Xmax | 8mm (One-Way) |
| Driver Displacement | 0.04 Cubic Feet (Published by Rockford Fosgate) |
| Driver Sensitivity | 83.0 dB |
| Driver Power Handling | 250 Watts RMS |
| Driver Overall Diameter | 8.720 Inches (Rockford Fosgate Spec) |
| Mounting Depth Required | 4.760 Inches (Rockford Fosgate Spec) |
| Cutout Diameter | 7.130 Inches (Rockford Fosgate Spec) |
| Material | Langboard Elite 3/4" MDF |
| Construction | ShopSabre CNC / Two Windowed C Braces At The Third Points, Seated On The Port Panel |
| Joinery | V-Groove and Dado (CNC-Cut) |
| Front Baffle Construction | Double-Layer 1.5" MDF | Cosmetic Front Layer Routed For The Acrylic Insert |
| Mounting Hardware | Threaded Inserts At Every Mounting Location | Stainless Steel Machine Screws Included |
| Voice Coil Configuration | Dual 2 Ohm |
| Terminal Cup | Proline X ABS/Carbon Fiber Composite | Side Mounted, Opposite The Port | 12g OFC Pre-Wired |
| Damping | None - Ships Dry. Polyfill Detunes A Ported Enclosure |
| Recommended Power | 175-250 Watts RMS (Rockford Fosgate Rated: 250W RMS) |
| Carpet Finish | Plush Black |
| Weight | 41 lb |
| Bundle Options | Enclosure Only (Bring Your Own Rockford Fosgate P2D2-8) |
| Warranty | 1-Year Limited (Enclosure) |
| Manufactured | Tullahoma, Tennessee, USA |
Performance in this enclosure
01Is this driver right for a ported box?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
0.92 cu ft net against a 9.9 L Vas, vented at 35.5 Hz.
03Perceived Ported vs Sealed
This cabinet, 0.92 cu ft net vented at 35.5 Hz, against Rockford Fosgate's recommended sealed box, 0.23 cu ft.
04Real World Ported vs Sealed
The same two boxes with cabin gain applied, 45 Hz corner, 18 dB ceiling.
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 7.8 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.
Installer's take
Rockford's Punch P2 eight is a 39.6 Hz motor with a 0.46 Qts, and vented at 35.5 Hz in 0.92 cubic feet it reaches 30.3 Hz anechoic on 2.40 dB of ripple, a long way down for an eight. The cost is in the car: 7.22 dB of spread across 25 to 60 Hz, because a 40 Hz motor has rolled off well before cabin gain arrives and the port is carrying the bottom octave alone. Rockford's own sealed recommendation is 0.23 cubic feet, a quarter of this box; they are pitching a very different sound.
Excursion is the number I watch on this one. 7.8 mm of one-way travel and the cone uses 7.0 of it at 250 watts with the subsonic filter set, 90 percent of what it has. Set the filter, set the gain with a meter, and do not treat 250 watts as a starting point. The channel runs 20.3 metres per second against a 20.9 limit.
Questions
Why is this enclosure tuned to 35.5 Hz?
35.5 Hz puts the anechoic F3 at 30.3 Hz on 2.40 dB of ripple, a long reach for an eight, and the reach is what costs it in the car: 7.22 dB of spread across 25 to 60 Hz, because a 39.6 Hz motor has rolled off well before cabin gain arrives. Rockford's own sealed recommendation for this driver is 0.23 cubic feet; this is a different animal. The port takes 23.92 of the 24.88 inches available and runs at 20.3 metres per second in the channel against a 20.9 limit, 11.6 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 7.0 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 12.90 inches deep at the base and 8.62 at the top, 29.00 wide and 12 tall.
Do I need a subsonic filter?
Yes, at 28 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 P2D2-8 at 90 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 P2D2-8 at 250 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 90 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 Rockford Fosgate's recommended sealed box, 0.23 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 3.33 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 23.92 inches of path and 13.0 square inches of channel running at 20.3 metres per second, 53 percent of its turbulence limit. The three mouth edges are rounded over at 1/2 inch, so the opening at the face is 22.5 square inches and the air leaves it at 11.6 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 23.92 inches for 35.5 Hz. Stuff it and you move the tuning without shortening the port.
Is the P2D2-8 included?
No. This is an enclosure only, cut for the Rockford Fosgate P2D2-8 specifically: the 7.130 inch cutout, the 4.760 inch mounting depth allowance and the 0.92 cubic foot alignment all come from Rockford Fosgate's published parameters. It fits both coil versions; the alignment published here is the D2. Bring your own driver.
Other Performance Optimized models
- Dual Kicker Solo X 8" Subwoofers Dual 8" Sealed
- PowerBass XL-844 Dual 8" Sealed
- Alpine S2-W8 Single 8" Ported
- Arc Audio ARC 8 Single 8" Ported
- Arc Audio ARC 8 Single 8" Ported
- Image Dynamics ID8 V4 Single 8" Ported
- Image Dynamics ID8 V4 Single 8" Ported
- Image Dynamics IDQ8 V4 Single 8" Ported