Ground Shaker GS-RGM18B Single 8″ Sealed Sub Box — Fits 07–13 GMC Sierra Crew Cab
Enclosure only — subwoofers not included.
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Ground Shaker GS-RGM18B Single 8″ Sealed Sub Box — Fits 07–13 GMC Sierra Crew Cab
Product Overview
Description
Built for the 07–13 GMC Sierra Crew Cab, this is Ground Shaker's single 8" sealed enclosure, and it sits under the rear seat and fires upward. It is a sealed box, so expect clean, tight low end that blends with the rest of the system rather than overpowering it, and the 0.85 cubic feet of air volume suits most 8" subs.
Key Features
- Vehicle-specific enclosure for the 07–13 GMC Sierra Crew Cab
- Single 8″ sealed design — 0.85 ft³ air volume
- Mounting depth 5 1/2″
- 5/8″ high quality MDF wood
- Carpeted with durable trunk liner finish
- Sealed with high quality Titebond silicone
- Glued with high quality Titebond wood glue
- 1 spring loaded terminal
- Fits under rear seat
- Upward firing
- 2007 fits only the new body estyle
Specifications
| SKU | GS-RGM18B |
| Application | 07–13 GMC Sierra Crew Cab |
| Enclosure Type | Sealed |
| Woofer Size | Single 8″ |
| Cutout Diameter | 7 1/8″ |
| Air Volume | 0.85 ft³ |
| Weight | 23 lbs |
| Mounting Depth | 5 1/2″ |
| Height | 7 1/4″ |
| Length | 32 1/4″ |
| Depth | 14 3/4″ |
Subwoofer option
Add one DS18 SRW8.4 shallow-mount 8" subwoofer — 150W RMS / 300W MAX, SVC 4-ohm, 2.95" mounting depth, 7.12" front-mount cutout per DS18's dimension drawing — and it ships with the box, one per woofer opening. This box is cut 7 1/8″ with 5 1/2″ of mounting depth, so the SRW8.4 fits as shipped. Choose "Box only" to buy the enclosure alone.
Box-only option: subwoofers not included. Price is each.
Free shipping on orders $150+
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
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FAQs
Please read our FAQs page to find out more.
RMS vs. MAX power — which number do I actually care about?
RMS is what your gear handles continuously; MAX is the short burst it can survive without complaint. Match your amplifier's RMS output to your speakers' RMS rating — sizing off the MAX number is how magic smoke gets released.
What does the IP65 rating on DS18 marine gear actually mean?
It's dust-tight and rated against low-pressure water jets from any direction — built for spray, rain, and the occasional wave over the bow, not for full submersion. If something's going somewhere it could sit underwater, that's a different conversation entirely.
How do I match an amplifier to my speakers without guessing?
Add up the RMS rating of everything the amp will power, and pick an amp whose RMS output (at your speakers' impedance — usually 4-ohm) lands close to that total. Undersized is thin sound; wildly oversized is a fast way to blow a voice coil.
Can I mix marine-grade gear into a standard car audio setup, or the reverse?
You can run marine-grade gear in a car — it's just over-built for that environment, no downside besides cost. Running non-weatherproof car audio gear in an open UTV or boat is the direction that causes problems.
What gauge wiring kit do I need?
It scales with your amp's power draw and the length of the run — DS18's OFC kits come in 4-gauge and 8-gauge for a reason. Undersized wiring on a high-draw system is a voltage-drop and heat problem waiting to happen; when in doubt, size up.