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
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 behind 2nd row, floor-level |
|---|---|
| Outer bounding box | ~39"W x 21"D x 7"H per a real forum-documented build for a bottom-firing compact enclosure. Mazda-published cargo room (2023 and 2025 decks): width between the rear tire houses 40.2 in (40.3 in Hybrid), width at floor 55.6 in, length behind the 2nd row 42.6 in (43.1 in Hybrid), tailgate opening 41.7 in W x 27.5 in H, floor-to-roof height 30.2 / 29.6 in (two figures; the column labels are not legible in the extract), threshold height 28.4 in (29.8 in Hybrid). The forum 39"W box fits inside Mazda's 40.2 in between the tire houses. |
| Known obstructions | None specifically documented beyond general cargo-area use. |
| Usable volume estimate | 3.4 ft³ |
| Location | spare tire well under the cargo floor |
|---|---|
| Outer bounding box | not independently measured as a raw envelope — the reference build seals the wheel's own mounting holes and builds directly into the wheel cavity itself, so the 'envelope' is effectively the spare tire's own dimensions, not a separate measured pocket |
| Known obstructions | Requires sealing the wheel's factory mounting/lug holes and fabricating an MDF cap — a genuine custom build, not a drop-in product. Mazda's 2023 and 2025 spec decks list a T155/90D17 temporary spare as standard on every trim, Bose included, so a well build means giving up or relocating the spare (2026-10-02). |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x8" or 1x10" compact sealed, quick-disconnect |
|---|---|
| Box type | sealed |
| Location | headrest-mounted (documented pattern: clips into a baby-seat tether anchor, quick-disconnect wiring) |
| Subwoofers | 1x10" shallow, custom spare-wheel-well build (documented pattern, JL Audio shallow driver) |
|---|---|
| Box type | sealed, custom-built into the spare wheel cavity |
| Location | spare tire well — requires sealing factory wheel mounting holes and fabricating an MDF cap, a genuine build project not a drop-in |
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 | 2.75" per real Crutchfield-sourced fitment data — an unusually small factory driver size for a front door location. |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | Front UPPER door panel — confirmed via Crutchfield fitment data, distinct from the 2.75" main door speaker. Exact diameter not confirmed. |
| Factory speaker size | 2.75" per real Crutchfield-sourced fitment data, same as front. |
|---|---|
| Known obstructions | None specifically documented |
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeter is upper front door mounted, front only |
| Factory amp / premium audio | Bose premium system (available trims): 12 speakers total, with BassMatch, AudioPilot, and Centerpoint processing technologies, and a factory subwoofer mounted in the rear tire well — meaning the factory sub already lives in the same general area (spare tire well) that the best aftermarket reference build also targets. Non-Bose base trims have no factory subwoofer; a forum thread ('Subwoofer install for Non Bose trims') specifically covers adding one to these trims, confirming this is a common, well-covered upgrade path. Exact per-speaker sizes for either system not independently confirmed. Mazda spec decks: base trims have an 8-speaker system; the Bose 12-speaker system (Centerpoint 2, AudioPilot 2) is standard on the 2.5 S Premium, 2.5 S Premium Plus, 2.5 Turbo Premium and 2.5 Turbo Premium Plus (2023), and the 2025 deck keeps the 8-speaker base and Bose on the upper packages. CONFLICT: neither deck lists a subwoofer, so the factory sub in the rear tire well above is not sourced by Mazda; and both decks list a "Temporary spare tire" (T155/90D17) as standard on every trim, including Bose trims. |
|---|---|
| Adding subs without a head-unit swap | Confirmed as a common, well-documented path on both Bose and non-Bose trims via the cx50forums.com threads ('How I added a new subwoofer to the factory Bose system', 'Subwoofer install for Non Bose trims') — exact tap point/part number not independently confirmed. |
| Head unit | No replacement needed |
Genuinely active, well-documented build culture for this vehicle (its own dedicated forum, cx50forums.com, with multiple real threads) — better-than-average sourcing for a newer model. Real cargo-area figure: a builder reports ~39"W x 21"D x 7"H usable for a compact box, low enough (5-6") to still stack cargo on top. Real creative alternative: a small sealed box with a Pioneer 10" sub hangs off the headrest area, clipped into a baby-seat tether anchor point, with a quick-disconnect wire for easy removal — genuinely novel mounting location, same family as the Miata footwell/parcel-shelf patterns on other vehicles covered here.
Real spare-tire-well build: a builder created a custom enclosure IN the spare wheel itself — sealed the wheel's bottom mounting holes with rubber/aluminum washers, capped with MDF, cut a hole for a JL Audio shallow 10" driver, strapped together.
CX-50 Hybrid: HV battery sits under the cargo floor, rear passenger (right-hand) side — a modest cargo-capacity cost exists (31.4 ft3 standard vs. 29.2 ft3 Hybrid, a 2.2 ft3 difference), but multiple sources describe the real-world loading experience as equivalent since the reduction comes from underfloor cubby space, not the main cargo well shape. Treat as the Infiniti Q50/Mercedes GLE-450e pattern already established in this catalogue (hybrid trims can quietly shrink capacity without a dramatic floor-raise) — check Hybrid-specific cargo figures before assuming parity with the gas model, but it does not appear to block a build the way a true floor-raising PHEV pack would.
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.