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 Crossover
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | under front passenger seat (zero cargo loss) or behind rear seat (factory powered option) |
|---|---|
| Outer bounding box | Cargo width between wheel housings ~43"; liftgate opening ~42"W x 29"H; not independently measured for a specific box footprint |
| Known obstructions | Trapezoid-shaped boxes recommended for custom builds to minimize sound wave cancellation |
| Usable volume estimate | 0.5 ft³ |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | under-seat passive (e.g. MSP 25-style) |
|---|---|
| Box type | sealed |
| Location | under front passenger seat, zero cargo loss |
| Subwoofers | OEM Kicker 10" powered unit, or custom trapezoid box |
|---|---|
| Box type | sealed |
| Location | behind rear seat |
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 | 6-3/4" |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | Dash-corner-mounted — confirmed (sources vary slightly, 3"-3.5", one owner fit a 4" aftermarket unit as a tight replacement). Plays from ~6kHz up with a small cap on the factory unit. |
| Factory speaker size | 5-1/4" |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeter is dash-corner mounted, front only |
| Factory amp / premium audio | Specific hardware spec confirmed. Harman Kardon premium audio on the Limited trim: 8 speakers, 432W. Boundary note for accuracy: a real 2024 Crosstrek finding (HK system gains a subwoofer) exists but falls OUTSIDE this page's 2018-2023 span — do not backdate that subwoofer addition into this generation without separate confirmation. Subaru trim sheets: 4 speakers (Base) and 6 speakers (Premium and up), the same two systems in 2018-2021 and 2023. The Harman Kardon system, "8 Harman Kardon speakers and 432-watt-equivalent Harman Kardon amplifier", is optional on Limited (2018-2023) and on the Hybrid (2023 sheet), bundled with the moonroof and 8.0-inch navigation. No subwoofer is listed for the Harman Kardon system in this generation. |
|---|---|
| Adding subs without a head-unit swap | Confirmed straightforward — the OEM Kicker accessory and under-seat options both avoid the head unit |
| Head unit | No replacement needed |
Subaru-published cargo (not 19.9 / 54.7, which no Subaru sheet shows): 20.8 ft3 behind the rear seats, 55.3 ft3 seats folded (Crosstrek Hybrid 15.9 / 43.1). Not from Subaru and not re-sourced: liftgate opening ~42"W x 29"H, folded load floor ~64"L, cargo width between wheel housings ~43". FACTORY OPTION: Subaru sells a genuine OEM Kicker-branded powered subwoofer (H630SFJ101) that's a self-contained unit mounting behind the rear seat — a real manufacturer accessory, not just third-party. For cargo-preserving builds, an under-seat passive subwoofer (e.g. MSP 25 under the front passenger seat) is a documented zero-cargo-loss option. Design tip found: a trapezoid-shaped box is recommended for custom builds to minimize sound wave cancellation.
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.