2016-2023 Mazda CX-9 2nd Gen — subwoofer box fitment

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

Where a box actually fits

These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.

Standard Solid

Locationcargo area behind 3rd row
Outer bounding box30.125"L x 15"H x 13.6875"W (dual-12" ported product footprint used as proxy)
Known obstructionsNone specifically documented
Usable volume estimate3.5 ft³

Starting points

Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.

Budget

Subwoofers1x10" or 1x12" sealed
Box typesealed
Locationcargo area behind 3rd row

Enthusiast

Subwoofers2x12" ported, 3.50 ft3 (real example above)
Box typeported
Locationcargo area behind 3rd row

Door speaker fitment

Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.

Front doors Likely

Factory speaker sizegenuinely odd-sized ~8"/8.5" mid-bass, NOT the common 6x8" — real owner measurement puts mounting holes at ~9" diagonally. Max mounting depth should stay under ~3.5"-4" to be safe.
Max mounting depth3.5 in
Known obstructionsReal non-standard factory size — don't assume a generic 6x8"/6.5" replacement will bolt in without checking
Adapter bracket neededyes
Tweetern/a in the doors — real, confirmed pillar-mounted tweeter, ~35mm (~1.38"), Bose-equipped trims. Genuinely larger than the sibling CX-5's own confirmed 25mm A-pillar tweeter despite the shared Bose branding — a real size difference between two Mazda SUVs, not assumed identical.

Rear doors Likely

Factory speaker size6.5"
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
Tweetern/a — tweeter is pillar mounted, front only

Factory audio integration

Factory amp / premium audioReal, clean, and consistent across this entry's ENTIRE 2016-2023 span — no mid-cycle change found, one of the more stable findings. Bose 12-speaker system confirmed on Grand Touring trim, matching Mazda's usual Grand-Touring-gates-Bose pattern (same as the CX-5 companion entry, one tier up in speaker count).
Adding subs without a head-unit swapConfirmed straightforward — cargo-area builds don't touch the head unit
Head unitNo replacement needed

Mounting locations

Standard Solid

Real cargo volume by row (1st/2nd/3rd row folded): 14.4/38.2/71.2 ft3 — genuinely large full capacity for the enthusiast tier. Real commercial specs: dual 12" ported Stage Series, 1000W RMS/500W peak at 2-ohm, 30.125"L x 15"H x 13.6875"W; alternate dual 12" ported, 3.50 ft3 total, 3/4" MDF, CNC-cut.

Builds and products found for this vehicle

Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.

Build it for this vehicle

Each link opens the tool with this vehicle already selected.

Before you cut anything

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.