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: CrewMax
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | underseat, CrewMax (aftermarket storage products confirm the underlying cavity shape) |
|---|---|
| Outer bounding box | Real storage-product data: plastic 3-compartment layout — two outer sections 10.125"x9.875" (4.5"D each), middle section 10.125"x13.875" (4"D); alternate single-compartment aluminum box 45.5"L x 10"W x 3.625"D. Genuinely SHALLOW cavity — max depth found across all sources tops out around 4.75" (matching the Skar Audio box's mounting depth already in this page). Vehicle-specific enclosure catalogues; published box footprints are lower bounds on the cavity, not the cavity: TacoTunes '2007-2021 Toyota Tundra CrewMax Ported Subwoofer Box Enclosure (SINGLE 12)': 51 x 11 x 24 in (as printed; axes not labelled), 1.45 ft3, hide behind the seats; NET Audio '2014-2021 Toyota Tundra Crewmax Sub Box Sealed': 48 x 7 x 22 in (as printed; axes not labelled), 1.08 ft3, behind seat; NET Audio '2014-21 Toyota Tundra Crewmax Sub Box Under Seat Box Sealed': 50 x 21 x 5 in (as printed; axes not labelled), 1.84 ft3, under seat, where the truck floor steps up. Vehicle-specific enclosure catalogues; published box footprints are lower bounds on the cavity, not the cavity: Ground Shaker 'BLACK 8" DUAL SEALED SUB BOX, FITS 14-21 TOYOTA TUNDRA CREW-MAX': Height 16", Length 52 1/2", Top Depth 3 1/4", Bottom Depth 6 3/4" (labelled by Ground Shaker), 1.44 FT^3 total; 0.72 FT^3 per subwoofer, FITS BEHIND REAR SEAT; Ground Shaker 'BLACK 10" TW3 DUAL SEALED SUB BOX, FITS 14-21 TOYOTA TUNDRA CREW-MAX': Height 16", Length 52 1/2", Top Depth 3 1/2", Bottom Depth 7" (labelled by Ground Shaker), 1.44 FT^3 total; 0.72 FT^3 per subwoofer, FITS BEHIND REAR SEAT. |
| Known obstructions | The compartmentalized factory layout (three separate sections rather than one open cavity) suggests internal structure/ribs divide the space — a single large box may not have as much continuous depth as the outer bounding box implies |
| Usable volume estimate | 1.3 ft³ |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x10" (single-sub equivalent) |
|---|---|
| Box type | ported |
| Location | behind rear seat, seat removal required |
| Subwoofers | 2x10" ported, 1.75 ft3, tuned 37Hz |
|---|---|
| Box type | ported |
| Location | behind rear seat, seat + back-wall padding removal required, confirm sub frame size before ordering |
Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.
| Factory speaker size | resembles a 6x9" aftermarket footprint — genuine factory speaker requires an adapter for actual 6x9"/6.5"/6.75" aftermarket replacements |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | yes |
| Factory speaker size | 6-3/4" woofers + tweeters |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | Rear door-mounted (CrewMax rear doors) — confirmed, exact diameter not independently confirmed. Genuinely different from the front, which has no door tweeter at all (front tweeter is dash-corner instead) — a real front/rear asymmetry, not a copy-paste assumption. |
| Factory amp / premium audio | Specific, well-sourced (a wiring-diagram PDF naming exact trims, stronger than typical forum sourcing). JBL premium system confirmed on Limited, Platinum, 1794 Edition, and TRD Pro trims — named, matches our other Toyota top-trim JBL findings. Base SR/SR5 trim status not confirmed either way. |
|---|---|
| Adding subs without a head-unit swap | Confirmed straightforward, though rear seat removal is required (more involved than most trucks' under-seat swaps) |
| Head unit | No replacement needed |
Specific full spec: Fox Acoustics dual 10" vented — 1.75 ft3 air volume, tuned 37Hz, 9.125" mounting hole, 3.75" mounting depth, 6" max magnet diameter. INSTALL CAVEAT: the rear seat must be fully removed for installation, and padding on the back wall must also be removed for proper fit — subs with larger frames will require trimming by the installer. Skar Audio's dual-10" ported alternative has a slightly deeper 4.75" mounting depth.
Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.
Each link opens the tool with this vehicle already selected.
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.