2020-2025 Buick Encore GX 1st 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 Subcompact Crossover

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 Likely

Locationbehind rear seats or trunk, down-firing
Outer bounding boxNo independently measured raw cavity envelope found — the real removable 12" shelf build is the best available reference point.
Known obstructionsThe factory spare-tire-area driver is primarily an ANC (Active Noise Cancellation) component on non-Bose trims, not a real bass source — don't plan a build assuming it's a repurposable audio subwoofer without first confirming trim level.

Starting points

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

Budget

Subwoofers1x under-seat powered unit (real documented owner approach for improving the non-Bose base system)
Box typen/a — powered unit, under-seat
Locationunder seat

Enthusiast

Subwoofers1x12" custom, removable shelf-mounted behind the rear seats (real documented owner build)
Box typecustom, removable
Locationtrunk, behind rear seats

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 Solid

Factory speaker sizeTRIM-SPECIFIC, corrected/expanded 2026-07-22 — real, precise Go-Parts.com sourcing confirms the standard and Bose systems are NOT the same hardware: STANDARD (non-Bose) trims run a 6.5" front door woofer. BOSE Premium trims run a larger 7.5" (+/-0.5") front door woofer, different wiring, and a separate dedicated amplifier — confirmed explicitly NOT interchangeable with the standard system's speakers. Earlier note about A-pillar tweeters was corrected — that part is for the OLDER, unrelated 'Encore' (no GX suffix, 2013-2022 China-built model, a separate entry candidate); it does NOT apply to the Encore GX.
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
TweeterSTANDARD trims: mounted inside the front door panel, directly above the main 6.5" woofer (real, confirmed door-mounted location, NOT A-pillar). BOSE trims: tweeter present as part of the component set but exact mount point not independently confirmed.
Midrangen/a — this is a 2-way system (woofer + tweeter) on both trims, no separate dedicated midrange driver confirmed

Rear doors Solid

Factory speaker sizeTRIM-SPECIFIC: STANDARD trims run 6.5" (same as front). BOSE Premium trims run a smaller 5.25" rear door woofer — a real, confirmed front/rear size split on the Bose system specifically (front 7.5" / rear 5.25"), unlike the standard system's uniform 6.5" front and rear.
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
Tweetern/a — no rear tweeter confirmed on either trim

Factory audio integration

Factory amp / premium audioBose Premium system (available trims): the ONLY trim where the spare-tire-area driver functions as a genuine audio subwoofer rather than primarily an ANC component. Standard (non-Bose) trims: the same physical driver location exists but is limited and ANC-focused, not a meaningful bass source.
Adding subs without a head-unit swapConfirmed via multiple real forum threads, including a recently-active (February 2026-dated) thread specifically titled about accessing the trunk-area subwoofer for an install — genuinely current, ongoing build interest.
Head unitNo replacement needed

Known integration products

Mounting locations

Standard Likely

GENUINELY IMPORTANT FINDING, worth flagging prominently before anyone assumes the factory 'spare tire subwoofer' is real bass: on the STANDARD (non-Bose) system, that spare-tire-area driver exists PRIMARILY FOR ACTIVE NOISE CANCELLATION, not audio — real owner sourcing describes it as containing only a 6" or 4" driver and being 'limited' even on the Bose Premium setup, where it does at least contribute to actual audio. Real, specific builds confirmed: a shelf built for a 12" driver behind the rear seats, using the trunk's maximum enclosure volume while remaining easily removable without any permanent vehicle modification; a separate real recommendation favors a properly-sized down-firing sealed box in the trunk for better sound quality.

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.