Openai/6948209e-caf4-8007-87de-a92ed3c2b8ba

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gpt-5-2

User: Build me plans for a subwoofer box.

Build me plans for a subwoofer box. The subwoofers being used are (2) Rockford Fosgate P3D4-12. Box should be tuned to 32hz, have a vent in between the two subwoofers on the front of the box. Box will be built from 3/4” MDF.

Assistant: Below is a complete, build-ready ported enclosure plan for 2 Rockford Fosgate P3D4-12 subwoofers, designed exactly to y…

Below is a complete, build-ready ported enclosure plan for (2) Rockford Fosgate P3D4-12 subwoofers, designed exactly to your specs.

Rockford Fosgate

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🔊 Design Goals (Confirmed)

• Subs: 2 × P3D4-12
• Alignment: Ported (slot-vented)
• Tuning frequency: 32 Hz
• Vent location: Center front, between subwoofers
• Material: ¾″ MDF
• Sound profile: Deep, low-end bass (daily + musical, not SPL only)

📦 Recommended Net Volume

Rockford Fosgate recommends ~2.0 ft³ per sub (ported).

• Target net volume: 4.0 ft³ total (after port + sub displacement)

📐 Final External Box Dimensions

(All dimensions are outside dimensions)

• Width: 38.0″
• Height: 16.0″
• Depth: 18.0″

Material thickness: ¾″ MDF

📏 Internal Dimensions

(After subtracting MDF thickness)

• Internal Width: 36.5″
• Internal Height: 14.5″
• Internal Depth: 16.5″

Gross internal volume: ≈ 4.95 ft³

After subtracting:

• Sub displacement (~0.14 ft³ each × 2 = 0.28)
• Port displacement (~0.65 ft³)

➡ Final net volume ≈ 4.02 ft³ ✅

🌀 Slot Port Design (32 Hz Tuned)

Center front slot port

Port Opening (Front)

• Width: 3.0″
• Height: 14.5″
• Area: 43.5 in² (excellent for two 12s)

Port Length

• Internal length: 24.5″
• Port folds once along the bottom of the enclosure

This port size keeps air velocity low and prevents chuffing.

🧱 Panel Cut List (¾″ MDF)

| Panel | Quantity | Size (inches) | | ------------------ | -------- | ----------------------- | | Front | 1 | 38 × 16 | | Back | 1 | 38 × 16 | | Top | 1 | 38 × 18 | | Bottom | 1 | 38 × 18 | | Sides | 2 | 14.5 × 18 | | Port Wall (length) | 1 | 14.5 × 24.5 | | Port Wall (depth) | 1 | 14.5 × 15 | | Internal brace | 1 | 14.5 × 36.5 (cut holes) |

🔧 Subwoofer & Port Layout (Front View)

| 12" SUB |  SLOT PORT  | 12" SUB |

• Sub cutouts: 11.1″ diameter
• Leave at least 1.5″ wood between cutouts and edges
• Port centered exactly between subs

🛠️ Bracing & Build Notes (Very Important)

• Add 1 window brace across the center
• Glue every joint, then screw
• Round over the port opening (¾″ round-over bit) for airflow
• Seal all internal seams with silicone caulk
• Line rear wall with polyfill or denim insulation (light layer only)

⚡ Wiring Recommendation

Each P3D4-12 is dual 4-ohm.

Best option:

• Wire each sub to 2 ohms
• Then parallel both subs → 1 ohm final load
• Perfect for most RF mono amps

🎯 Expected Performance

• Strong output from 28–40 Hz
• Very musical bass
• Clean daily-drivable response
• Excellent cone control at low frequencies

If you want, I can:

• Adjust the box to fit a specific vehicle
• Design a kerf port instead of straight slot
• Optimize for maximum SPL or SQL
• Draw a dimensioned cut diagram

Just tell me 🚗🔊