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 Sedan
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | trunk, through existing opening |
|---|---|
| Outer bounding box | Not independently measured — single documented build used 1.37 ft3 ported, 1/2" MDF |
| Known obstructions | On the 2015 12-speaker Harman Kardon system Subaru's press kit names "a rear subwoofer"; where it mounts is not stated. No other obstruction documented. |
| Usable volume estimate | 1.37 ft³ |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x10" sealed |
|---|---|
| Box type | sealed |
| Location | trunk |
| Subwoofers | 1x10" or 1x12" ported, 1.37 ft3, tuned 31Hz |
|---|---|
| Box type | ported |
| Location | trunk |
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 | unconfirmed — Crutchfield fit-database coverage confirmed to exist but specific dimensions not surfaced |
|---|---|
| Adapter bracket needed | unconfirmed |
| Factory speaker size | unconfirmed |
|---|---|
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeter is dash-corner mounted, front only |
| Factory amp / premium audio | Harman Kardon premium audio on the Limited and 3.6R Limited in every year 2015-2019 (Subaru trim sheets), but not the same system every year. 2015: 12 Harman Kardon speakers and a 576-watt-equivalent amplifier, standard; Subaru's 2015 press kit says the 12 speakers "include a front center speaker and a rear subwoofer". 2016: 8 Harman Kardon speakers and a 440-watt-equivalent amplifier are standard; the 12-speaker, 576-watt-equivalent system is an option with navigation. 2017: the 12-speaker, 576-watt-equivalent system standard, and optional on the Sport. 2018: 12 speakers with a 576-watt-equivalent GreenEdge amplifier, standard. 2019: the 12-speaker, 576-watt-equivalent system on the Limited and 3.6R Limited. Other trims: 4 speakers on the 2.5i, 6 on the Premium and the Sport. The trim sheets print no separate subwoofer line; whether the 2016 eight-speaker system and the 2017-2019 systems keep the rear subwoofer is not stated. |
|---|---|
| Adding subs without a head-unit swap | Confirmed straightforward — trunk-based builds don't touch the head unit |
| Head unit | No replacement needed |
Subaru's trim sheets give "Trunk volume" 15.0 cu ft for every trim in each year 2015-2019, with no SAE or EPA label: a luggage rating, not a box dimension. Specific build: 1.37 ft3 ported enclosure, tuned 31Hz, 1/2" MDF construction. Earlier Legacy GT Wagon-era product (0.65 ft3, up to 6.95" mounting depth) is shared with the Outback wagon page of a similar era — same platform, different body style.
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.