2007–2018 GM Crew Cab – Quad 8" Ported Under‑Seat Subwoofer Box Plans
Subwoofer Box Plans for (4) 8" Subwoofers – Under‑Seat Ported Enclosure
Build a powerful, space‑efficient under‑seat ported enclosure for four 8" subwoofers with these precision‑engineered box plans. Designed specifically for 2007–2018 GM/Chevy/GMC Crew Cab trucks, this enclosure maximizes airspace, output, and cabin gain while maintaining full rear‑seat functionality.
Perfect for truck owners who want big bass without sacrificing interior space.
Save Money — Build It Yourself
Stop wasting materials and guessing on dimensions. These DIY subwoofer box plans make it simple to build a professional‑grade enclosure at home, giving you premium performance without paying custom‑shop prices.
What’s Included
- Downloadable ZIP file
- Multiple 3D rendering images
- Detailed spec sheet with subwoofer & enclosure specs
- Professional optimized cut sheet with parts list
- Precision‑designed under‑seat ported enclosure layout
Designed For
2007–2018 GM Crew Cab Trucks – Quad 8" Ported Enclosure
- Woofer Capacity: (4) 8" subwoofers
- Fitment: 2007–2018 Chevy Silverado / GMC Sierra Crew Cab
- Seat Lift Required: 2.5"
- Outside Dimensions:
- Width: 55"
- Front Height: 11"
- Rear Height: 8"
- Depth: 16"
- Center Hump: 15" wide × 1.5" tall
- Tuning: Manufacturer‑optimized ported design
- Performance Notes: Engineered for strong low‑frequency output, excellent cabin gain, and efficient airflow in limited under‑seat space
May work for other 8" woofers and other truck models — user discretion advised.
Why These Plans Perform
- Optimized specifically for the 2007–2018 GM Crew Cab under‑seat area
- Designed for four 8" subs to maximize cone area and output
- Smooth, predictable response thanks to proper airspace and port tuning
- Maintains full rear‑seat usability with only a 2.5" lift
- Ideal for daily setups needing clean, punchy, and powerful bass
- Eliminates trial‑and‑error and prevents wasted materials