2004-2009 Toyota Prius 2nd Gen (XW20) — 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: 5-Door Liftback/Hatchback

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.

Trunk Unconfirmed

Locationtrunk side panels or under rear seat
Outer bounding boxNo independently measured raw cavity envelope found.
Known obstructionsNone specifically documented for the cargo area itself.

Starting points

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

Budget

Subwoofers1x8" powered, under rear seat (if space allows)
Box typen/a — powered unit
Locationunder rear seat

Enthusiast

Subwoofers1x8" or 1x10" sealed, custom-built
Box typesealed, custom
Locationtrunk side panel

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 size6.5"/6.75" midbass — real, confirmed via named genuine OEM JBL parts (front door speaker, part 861600WB40).
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
TweeterFront door (paired with the 6.5"/6.75" midbass). REAL, IMPORTANT SAFETY CAUTION found: relocating this tweeter to the A-pillar (a real, documented DIY mod some owners attempt) drops the total load the factory amp sees to as low as 1.3 ohms — a genuinely dangerous impedance for most amps, which typically shouldn't go below 2 ohms; a real risk of amp damage, not just a sound-quality tradeoff.

Rear doors Unconfirmed

Factory speaker sizenot independently confirmed by exact size
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
TweeterRear door

Factory audio integration

Factory amp / premium audioJBL-branded factory stereo systems existed on this generation, but real sourcing confirms neither the standard nor JBL system includes a TRUE factory subwoofer — a genuine, sourced absence rather than an unresearched gap. Real, complete JBL layout confirmed via named OEM parts: 6.5"/6.75" front door midbass + 0.75" front door tweeter, rear door tweeter (distinct part number), and a 3"-4" front center dash speaker.
Adding subs without a head-unit swapConfirmed as commonly attempted via general amp/sub install guides spanning this and later generations (e.g. a real '2009-2019 Toyota Prius Amp and Sub Install' video explicitly bridges this era into the 3rd Gen).
Head unitNo replacement needed

Known integration products

Mounting locations

Trunk Likely

Real, general (not deeply generation-specific) sourcing confirms trunk side panels and under-the-rear-seat as the two most commonly cited locations for this generation. No named commercial molded enclosure specific to THIS generation was confirmed — the real NVX product already (BE-TOY-PRIG3-NSW104V2) is explicitly for the 3rd Gen (2010-2015), not this one; flagged rather than assumed to carry over.

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.