2014-2018 Chevrolet Silverado 1500 GMT K2XX — subwoofer box fitment

What we researched for this specific generation: where an enclosure actually fits, what the factory speakers are, how the factory audio is wired, and which real builds and commercial products exist for it. Confidence badges say how well each figure is sourced — this is research, not manufacturer spec.

Body styles covered: Regular Cab, Double Cab, Crew Cab

Where a box actually fits

These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.

Crew Cab Likely

Locationunderseat storage compartment, crew cab (2007-2018 shared this cavity per aftermarket storage-drawer sourcing)
Outer bounding box54"W x 13"D x 6.5"H (rear) tapering up to 9.5"H (front)
Known obstructionsNone specifically documented beyond the height taper front-to-rear already captured in the bounding box
Usable volume estimate3 ft³

Starting points

Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.

Budget

Subwoofers1x10" or 1x12" sealed
Box typesealed
Locationunder rear seat

Enthusiast

Subwoofers2x8" ported (real named option: Skar Audio vehicle-specific enclosure) or 2x10" downfire loaded (Subthump/AudioControl)
Box typeported or sealed loaded
Locationunder rear seat

Door speaker fitment

Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.

Front doors Solid

Factory speaker sizefactory oval, compatible with 5.25"/6.25"/6.5" aftermarket via adapter
Known obstructionsNone specifically documented
Adapter bracket neededyes

Rear doors Solid

Factory speaker size6-3/4" — same size for Crew Cab (full-size rear doors) and Double Cab (slightly smaller rear doors)
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed

Factory audio integration

Factory amp / premium audioBose 7-speaker available starting at LT trim (later model years); base trims have no factory amp
Adding subs without a head-unit swapStandard LOC tap should work on non-Bose trims. Bose-equipped trims need a Bose-specific adapter, not a generic LOC — verify trim before recommending a part.
Head unitNo replacement needed

Known integration products

Mounting locations

Crew Cab Likely

Real builder box referenced below: underseat dual 8" box, ~2 cu ft internal, tuned 32Hz. Full interior cavity dimensions not yet independently measured — box was designed around the specific sub pair, not a generic max-fit cavity spec.

Builds and products found for this vehicle

Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.

Build it for this vehicle

Each link opens the tool with this vehicle already selected.

Before you cut anything

Measure your own vehicle. Trim levels, factory subwoofer options, and mid-generation changes all move these numbers, and a box cut to a researched figure that does not match your truck is wasted wood. Where a badge reads Unconfirmed, treat the value as a starting point for your own measurement, not as an answer.