2008–2018 GM Sierra Crew Cab Dual Sundown Audio Z‑8" Subwoofer Box Plans
Subwoofer Box Plans for (2) Sundown Audio Z‑8 8" – Ported Truck Enclosure
Build an extreme‑output, deep‑tuned ported enclosure for two Sundown Audio Z‑8 8" subwoofers with these precision‑engineered subwoofer box plans designed specifically for the 2008–2018 GMC Sierra & Chevy Silverado Crew Cab. This enclosure maximizes under‑seat airspace, airflow efficiency, and low‑end extension while maintaining full rear‑seat usability.
The Sundown Z‑8 is known for its massive motor structure, high excursion capability, and shockingly deep output for an 8" driver. This enclosure provides the ideal airspace, port area, and tuning frequency needed to deliver violent lows, strong cabin gain, and clean daily performance inside the GM truck cabin.
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 huge, clean bass 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 ported truck enclosure layout
Designed For
Dual Sundown Audio Z‑8 8" Subwoofers – 2008–2018 GM/Chevy/GMC Crew Cab
- Woofer Type: (2) Sundown Audio Z‑8
- Woofer Size: 8"
- Outside Dimensions: 12”FH x 9”RH x 54”W x 15”D
- Requires 3.5" Seat Lift
- Tuning: 33–35Hz truck‑optimized ported design
- Performance Notes: Engineered for extreme low‑end output, strong cabin gain, and clean daily performance
May work for other 8" woofers — user discretion advised.
Why These Plans Perform
- Optimized specifically for dual Sundown Z‑8s
- Designed to fit 2008–2018 GM Crew Cab with proper seat lift
- Ported layout maximizes airflow and reduces turbulence
- Smooth, predictable response thanks to proper port tuning
- Ideal for daily setups needing clean, musical, and extremely powerful bass
- Eliminates trial‑and‑error and prevents wasted materials