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, bolted to the sub-frame (free-air design, no conventional box) |
|---|---|
| Outer bounding box | n/a — free-air design has no defined box envelope by nature; the 250mm driver itself is the only fixed dimension |
| Known obstructions | none reported beyond the design intentionally using the trunk/sub-frame structure itself as the acoustic space |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | Alpine SWE-815 via front-woofer signal tap + Wavetech LinkDQ converter (real, confirmed install, thread covers both S90 and V90) |
|---|---|
| Box type | n/a — powered unit, factory-tap integration |
| Location | trunk |
| Subwoofers | factory B&W 'Fresh Air' 250mm carbon-fiber subwoofer (if upgrading from base Momentum trim's audio) |
|---|---|
| Box type | factory, free-air |
| Location | trunk, bolted to sub-frame |
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 | real spec confirms 3x 100mm + 4x 80mm Kevlar midrange drivers across the full system, exact door allocation not independently broken out |
|---|---|
| Adapter bracket needed | unconfirmed |
| Tweeter | 'Tweeter-on-top' design — real, confirmed 25mm (1") Nautilus tweeter mounted on top of the door panel, one of the system's 6 total Nautilus tweeters (4 doors + center dash + confirmed elsewhere as headliner/rear-panel on the sibling SUV entries). Same brand-wide B&W signature design confirmed across our whole Volvo lineup. |
| Midrange | One of the system's 100mm (~3.94") Kevlar midrange drivers, per door. |
| Adapter bracket needed | unconfirmed |
|---|---|
| Tweeter | Same 'tweeter-on-top' 25mm Nautilus design as the front, one per rear door — part of the same 6-tweeter system total. |
| Midrange | Rear doors get an 80mm midrange element per the system's 4x 80mm figure, rather than the front's 100mm unit — not independently confirmed as door-mounted vs. elsewhere in the rear cabin. |
| Factory amp / premium audio | Bowers & Wilkins confirmed as the real premium tier, developed specifically for the S90/V90 per B&W's own collaboration page — same 19-speaker/1400W architecture already documented on Volvo's SUV lineup, now confirmed shared with the sedan/wagon twins too. |
|---|---|
| Adding subs without a head-unit swap | Confirmed via a real thread explicitly titled to cover both this vehicle and the sibling V90 ('V90/s90 Aftermarket subwoofer amplifier cable') — an Alpine SWE-815 install tapping the front-woofer signal via an extension cable and a Wavetech LinkDQ high-to-low converter, no factory wiring cut. The V90-specific builds (JL Audio 8W7, Rockville SS8P under-seat) were NOT independently re-confirmed as S90-specific — flagged as plausible via the shared platform rather than assumed identical. |
| Head unit | No replacement needed |
Entirely missing model until now — Volvo's flagship sedan (existing Volvo coverage was S60/V60/XC40/XC60/XC90, all sharing a confirmed Bowers & Wilkins architecture). Real, confirmed: this generation shares the SAME B&W system family already documented on the XC60/XC90 — 19 speakers, 12-channel Class D amp, up to 1400W, six 25mm Nautilus tweeters, three 100mm + four 80mm Kevlar-cone midrange drivers, four long-throw woofers, and one 250mm 'Fresh Air' subwoofer with a carbon-fiber cone. Real, distinctive engineering detail: the subwoofer is bolted directly to the car's structural sub-frame (not a conventional box) specifically to minimize unwanted vibration — this is the same 'free-air, no-box, uses the cabin/structure as the acoustic space' philosophy already confirmed on the XC60, now cross-confirmed on the sedan too.
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.