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: Minivan
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | beneath the front driver/passenger seat cushions |
|---|---|
| Outer bounding box | Not a real open rectangular cavity. Only documented data point: ~1.5" vertical clearance under the driver's seat, enough for a compact powered under-seat subwoofer (Kenwood KSC-SW11 class), confirmed clear of airbag wiring and seat-rail travel. Passenger side is shallower/uneven due to floor vents. |
| Known obstructions | HV traction battery and its cooling-fan air path (both front seats, worse on passenger side per real incident report), 12V accessory battery (front passenger seat per most sources), factory JBL amplifier when the JBL premium system is fitted (also front passenger seat per retailer writeup) — this is genuinely contested space, not open volume. |
| Location | cargo area behind the 3rd row seats |
|---|---|
| Outer bounding box | Toyota's own spec sheet lists 33.5 ft3 total cargo volume behind the 3rd row (75.2 ft3 with 3rd row stowed, 101 ft3 with both rear rows folded), but that's a whole-cargo-area figure, not a rectangular envelope a custom box could be designed against. No forum build or commercial product was found that measured the actual usable footprint. |
| Known obstructions | 3rd row seats fold rearward into a floor recess rather than tumbling forward, but multiple owner reports describe the stowed row as sitting 'almost flat' — not fully flush with the surrounding load floor, so a box resting on/near that area needs to account for a real step. CORRECTED 2026-07-19: the optional spare tire (~$75 factory add) is available across ALL Gen 4 trims (LE, XLE, Limited, Platinum), not restricted to top trims as originally stated. It is NOT a floor-well spare like an SUV's — real installation-kit instructions describe it hanging on a cable hoist BELOW the vehicle body, lowered/raised through a small crank hole in the cargo floor, so it does not occupy cargo cavity space either way (equipped or not). This means the classic SUV 'spare-tire-well-as-subwoofer-location' pattern genuinely does not apply to this vehicle — checked and ruled out, not skipped. |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x compact powered under-seat sub (Kenwood KSC-SW11 class, or JBL BassPro Nano x2 per real owner preference) |
|---|---|
| Box type | sealed, factory-integrated powered unit |
| Location | front-row footwell, DRIVER'S side only — confirmed clean fit; avoid passenger side due to HV-battery vent obstruction |
| Subwoofers | 1x10" or 1x12" sealed, custom-built to the actual measured cargo area — no confirmed off-the-shelf envelope exists yet for this generation |
|---|---|
| Box type | sealed |
| Location | cargo area behind 3rd row; measure on-site rather than trusting a borrowed spec, since no rectangular bounding box has been confirmed |
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 | Non-JBL 'Audio Plus' 8-speaker base system: factory front door opening is a native ~6" mount. Real documented 2024 XLE upgrade thread used Kicker CSC654 6.5" speakers with a Metra 82-8148 6"-to-6.75" multi-adapter to make them fit. (JBL 12-speaker premium system uses '2 front door woofers' in the same location — exact factory size not confirmed.) |
|---|---|
| Known obstructions | None specifically documented beyond the mount-size mismatch itself. |
| Adapter bracket needed | yes — confirmed via Metra 82-8148 in a real build |
| Factory speaker size | Sliding (rear) doors, non-JBL system: same 2024 XLE thread used 6.5" speakers in the rear doors. (JBL system instead runs '2 rear door speakers' plus relocates the rear-most speakers to the C-pillars — exact factory size for either unconfirmed.) |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed for rear (confirmed for front via the same thread) |
| Factory amp / premium audio | JBL Premium Audio: 12 speakers including a liftgate-integrated subwoofer, marketed at 1200W, standard on Woodland Edition/Limited/Platinum, optional on XLE/XSE. External amplifier mounts under the front passenger seat — the same contested front-row zone as the 12V battery and (per some sources) the HV battery's cooling path. Base trims run an 8-speaker 'Audio Plus' system with no factory amp or sub. |
|---|---|
| Adding subs without a head-unit swap | Likely straightforward on non-JBL 'Audio Plus' trims via a standard line-out converter tap. JBL trims run DSP processing between the head unit and amplifier per forum discussion — how that complicates an aftermarket LOC tap on THIS generation specifically was not independently confirmed; flagged not researched rather than assumed either way. |
| Head unit | No replacement needed |
Real documented build (siennachat, 'Under-Seat Subwoofer Installation: Looking for tips'): a Kenwood KSC-SW11 compact powered sub fits cleanly under the DRIVER'S seat with ~1.5" clearance, clear of airbag wiring and seat-rail travel. The PASSENGER side is worse — same thread reports it sits unevenly against the seat rail and doesn't sit flat because of floor air vents there. Those vents are for HV-battery cooling (confirmed via a separate real incident: an owner blocked the vent with a clothing bag and the dash threw an immediate stop-and-tow warning within ~5 minutes) — so the passenger-side footwell is contested real estate (HV battery + its cooling path + the 12V battery +, on JBL trims, the amplifier all cluster in this same front-row zone per multiple independent sources). Driver's side is the cleaner of the two. For the rear cargo area: Toyota's own spec sheet gives 33.5 ft3 behind the 3rd row, but no forum or commercial source in converted that into an actual rectangular bounding box a custom build could target — see raw_cavity_envelope and the noted gaps.
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.