Stage 1
OEM-Plus Under-Seat Subwoofer Enclosure for GM Trucks
Stage 1 is the foundation of the CB Customs lineup — a clean, OEM-plus under-seat enclosure designed specifically for 2019–2026 GM trucks. This option is for customers who want real bass without sacrificing factory appearance or interior function.
Built in-house and engineered around the GM under-seat area, Stage 1 gives you a proper enclosure solution — not a generic prefab box shoved under the seat.
Fitment
Built Specifically for 2019–2026 GM Trucks
- Fits 2019–2026 GM trucks (under-seat fitment).
- 3D-modeled for precise under-seat fitment with an OEM-plus install.
- Rear seat functionality remains completely factory.
- Designed to look clean and intentional once installed.
Enclosure Specs
Internal Dimensions & Clearances
📐
Total Air Volume
2.3 ft³ total air space.
🧲
Mounting Depth
6 inches.
Note: Actual depth may vary based on subwoofer magnet size.
Note: Actual depth may vary based on subwoofer magnet size.
⬇️
Woofer Clearance
2.25 inches from the bottom of the enclosure to the floor.
What’s Included
What Comes with Stage 1
📦
Custom Under-Seat Enclosure
Precision-built enclosure engineered specifically for GM under-seat fitment.
Designed for clean output and long-term reliability.
🧵
Standard Black Vinyl Finish
Stage 1 comes standard in high-quality black vinyl for a factory-clean leather feel and look.
Optional color-matched vinyl upgrades are available.
🔌
Plug-and-Play Terminal Cup
Includes our custom 3D-printed CB Customs terminal cup for clean, reliable,
and easy amplifier connection.
🔊
Optional Loaded Configuration
Stage 1 is sold unloaded by default. You can choose to add subwoofers and receive
the enclosure fully loaded and ready to drop in.
Performance
What to Expect
Stage 1 is built for clean, controlled bass that integrates properly with factory or upgraded audio systems. It’s a big improvement over stock, while keeping the install subtle and OEM-looking.
Power handling and final impedance depend on subwoofer selection if you choose a loaded option. If you want help picking subs or matching an amp, reach out and we’ll point you in the right direction.
Built by CB Customs
Craftsmanship, Lead Time & Warranty
- Hand-built in Weatherford, Texas using CNC-cut panels and in-house assembly.
- Built to order — lead time is confirmed after purchase.
- Lifetime craftsmanship warranty on the enclosure.
- Real support — direct help before and after purchase if you have questions.
Questions?
Still not sure which stage or setup to go with?
Shoot us a text or call at (682) 516-3358, email sales@cbcustoms.net, or reach out below with your truck year and goals.