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: 4-Door SUV, 3-row
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | cargo area floor, behind 3rd row, with the factory removable cargo tray taken out |
|---|---|
| Outer bounding box | ~29"W x 18"+D x 6.25"H per a real DIYMobileAudio builder's report — a floor-level shallow pocket, not a deep well |
| Known obstructions | Requires removing the factory cargo tray first; on Harman Kardon-equipped trims, the factory subwoofer occupies part of this same general cargo-panel area (see audio_integration) — exact overlap between the factory sub's footprint and this open-floor space not independently confirmed. |
| Usable volume estimate | 1.38 ft³ |
| Location | underfloor cargo tray beneath the 3rd-row floor — likely the spare-tire/storage zone, not independently confirmed as distinct from the above |
|---|---|
| Outer bounding box | ~36-38"W x 12"D x ~6"H per Ascent-forum discussion — wider and shallower than the tray-removed floor figure above |
| Known obstructions | Spare tire location relative to this specific tray was not independently confirmed. |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x8" powered shallow-mount (real example: JL Audio CP108LG-W3V3, confirmed fit) |
|---|---|
| Box type | sealed, shallow-mount, powered |
| Location | cargo floor, factory tray removed |
| Subwoofers | 1x10" or 1x12" shallow sealed |
|---|---|
| Box type | sealed |
| Location | cargo floor, factory tray removed — verify exact depth against the two conflicting cargo-tray figures on-site before finalizing a build |
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 | 6x9" (Harman Kardon-equipped trims). Base-trim front door speaker size not independently confirmed. |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Factory speaker size | 6.5" coaxial (Harman Kardon-equipped trims, 4 total across both rear doors per the full 14-speaker system breakdown) |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeter is dash-mounted, front only |
| Factory amp / premium audio | Harman Kardon premium system (Limited/Touring trims): 14 speakers, 792W amp. Breakdown per forum sourcing: dash-mounted L/R coaxial pair (counted as 4 driver elements), 1 center-dash speaker, 2 front-door 6x9" woofers, 4 rear-door 6.5" coaxials, and 1 factory subwoofer in the hatch/rear cargo panel (passenger side, per most sources — one source instead describes it as 8", most describe 10", not fully resolved). Base/non-Harman trims do not get a factory subwoofer. |
|---|---|
| Adding subs without a head-unit swap | Real forum discussion exists specifically about amping the factory Harman Kardon 'Premium' system's signal without a head-unit swap (a documented DIYMobileAudio thread), confirming this is a live topic for Ascent owners, but a specific confirmed tap point/part number was not independently verified. |
| Head unit | No replacement needed |
Two distinct real data points found, not fully reconciled into one figure — treat as two separate candidate cavities, not the same space measured twice: (1) DIYMobileAudio forum builder reports that after removing the factory cargo tray, the open cargo-area floor measures ~29"W x 18"+D x 6.25"H (~1.377 ft3 as a flat box) — enough for a shallow-mount 12" driver; a JL Audio CP108LG-W3V3 (purpose-built shallow-mount) is reported by an Ascent-forum owner to 'fit perfectly' in this area. (2) Separately, the Ascent's own underfloor cargo tray (beneath the 3rd-row floor, likely the spare-tire/storage zone) is reported at ~36-38"W x 12"D x ~6"H. Whether these are the same physical pocket described two different ways, or two genuinely different underfloor areas, was not resolved — recommend a dedicated in-person measurement pass before treating either as a final spec.
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.