2016-2022 Lexus RX 4th Gen (AL20) — 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 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

Locationski-pass area (facing into cabin) or cargo area, standalone
Outer bounding boxNot independently measured — real documented build used 0.73 ft3 internal for a 12" driver
Known obstructionsSki-pass-area depth can increase further if the rear strut bar isn't required to stay in place
Usable volume estimate0.73 ft³

Starting points

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

Budget

Subwoofers1x10" sealed, ski-pass area (zero cargo-floor space lost)
Box typesealed
Locationski-pass area, facing into cabin

Enthusiast

Subwoofers1x12" sealed, 0.73 ft3, or 1x15" ported
Box typesealed or ported
Locationcargo area

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 size6x9" door woofer (8 ohm) — genuinely multi-driver factory setup, not a single coaxial; the midrange and tweeter are NOT door-mounted (see tweeter/midrange fields below)
Known obstructionsThe 2.5" midrange location has essentially no direct aftermarket replacement options per Crutchfield's own fit database — a real, hard-to-solve gap
Adapter bracket neededunconfirmed
TweeterA-PILLAR mounted, NOT in the door — real, confirmed 2cm (~0.79") unit at 8 ohm on Mark Levinson-equipped trims, per an OEM part listing for the 'Mark Levinson High Performance Front Pillar Tweeter Set.' A real correction to this entry's prior undifferentiated door-speaker figure: the tweeter physically lives in the A-pillar, not the door panel.
MidrangeDASH-mounted (6.5cm 'squawker'), NOT door-mounted — real, confirmed, separate from the 6x9" door woofer and the A-pillar tweeter.

Rear doors Likely

Factory speaker size6.2" rear woofer
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
TweeterReal, confirmed present (~1" unit) alongside the 6.2" rear woofer, but exact mount point (rear door panel vs. C-pillar/rear deck) not independently reconfirmed — the front-tweeter finding above (A-pillar, not door-mounted) raises real doubt this rear unit is literally door-panel-mounted either. Flagged rather than assumed.
Midrangen/a — no separate rear midrange confirmed

Factory audio integration

Factory amp / premium audioMark Levinson available on equipped trims (Lexus-exclusive partnership)
Adding subs without a head-unit swapConfirmed straightforward — both the cargo-area and ski-pass-area builds avoid the head unit
Head unitNo replacement needed

Known integration products

Mounting locations

Standard Likely

Real cargo space: ~29-30 ft3 behind rear seats, expands significantly with seats folded. Real documented build: 0.73 ft3 internal volume for a 12" driver. GENUINELY CREATIVE REAL BUILD LOCATION: DIY builders have used the factory 'ski-pass' area (the pass-through between the rear seats/trunk normally meant for skis or long cargo) and transformed it into a sub enclosure facing outward into the cabin — box depth can increase further if the vehicle doesn't need to retain the rear strut bar. This is a genuinely unusual mounting location specific to vehicles with a ski-pass feature, worth flagging as its own pattern to check for on other 3-row/luxury crossovers.

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.