Dual Rockford Fosgate T1S2 12" Up‑Fire Subwoofer Box Plans (2008–2018 GMC Crew Cab)
Subwoofer Box Plans for (2) Rockford Fosgate T1S2 12" – Up‑Fire Truck Enclosure
Build a powerful, clean, hard‑hitting up‑fire subwoofer enclosure for two Rockford Fosgate T1S2 12" shallow‑mount subwoofers with these precision‑engineered truck‑specific box plans. Designed to fit 2008–2018 GMC Sierra Crew Cab trucks (with a 2.5" seat lift), this enclosure delivers deep bass, excellent output, and optimized airflow while maintaining proper seat function and cabin comfort.
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, perfect for anyone wanting big bass in their GMC truck 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 up‑fire enclosure layout
Designed For
Dual Rockford Fosgate T1S2 12" Subwoofers – 2008–2018 GMC Sierra Crew Cab
- Woofer Type: (2) Rockford Fosgate T1S2 12
- Woofer Size: 12"
- Outside Dimensions: 54"W × 10" Front Height × 7" Rear Height × 15"D
- Fitment: Requires 2.5" seat lift
- Performance Notes: Engineered for tight, accurate bass with strong low‑end depth, optimized specifically for under‑seat truck applications
May work for other 12" woofers — user discretion advised.
Why These Plans Perform
- Optimized specifically for the Rockford T1S2 shallow‑mount series
- Designed to fit 2008–2018 GMC Sierra Crew Cab trucks with proper seat clearance
- Up‑fire design improves cone protection and enhances low‑frequency response
- Smooth, predictable performance thanks to proper airspace and tuning
- Ideal for daily setups needing clean, musical, and powerful bass
- Eliminates trial‑and‑error and prevents wasted materials