2021-2025 Kia Seltos 1st Gen (with a 2024 refresh) — 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 Solid

Locationpassenger-side rear cargo area, factory Bose sub location
Outer bounding boxNo independently measured raw cavity envelope found — multiple real named products (JL Audio 10" ported, Sound Ordnance 12") both confirmed to fit 'perfectly' are the best available reference points, suggesting genuinely generous available space for this vehicle's size class.
Known obstructionsNone specifically documented beyond the factory sub's own footprint.

Starting points

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

Budget

Subwoofers1x6.5" shallow-depth direct replacement (real named product: Memphis Audio + 400W mono amp)
Box typen/a — direct factory-location replacement
Locationpassenger-side rear cargo area

Enthusiast

Subwoofers1x10" ported (real named product: JL Audio, confirmed to fit perfectly) or 1x12" (Sound Ordnance box)
Box typeported or sealed, per product
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 size6.5" — confirmed via real forum sourcing; a real upgrade path exists using JL Audio C2-series component speakers.
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed
TweeterNot found despite a dedicated search — genuinely thin sourcing on the high-frequency side for this model, unlike its cargo/subwoofer side which is well-documented. Left honestly not researched rather than assumed from sibling Kia models, since tweeter presence/location varies meaningfully across this brand's lineup (see Sportage/Sorento/Telluride/Forte findings).

Rear doors Likely

Factory speaker size6.5" coaxial — real upgrade path confirmed using JL Audio coaxial speakers specifically for the rear (vs. component speakers up front), a genuine front/rear product-type distinction worth keeping.
Known obstructionsNone specifically documented
Adapter bracket neededunconfirmed

Factory audio integration

Factory amp / premium audioBose premium system (available trims, e.g. SX Turbo): includes the factory subwoofer discussed above — real owner consensus rates the factory bass output as genuinely weak ('almost no presence'), a specific, sourced critique rather than a generic 'could be better.'
Adding subs without a head-unit swapConfirmed via a real, specific tap point: splice into the speaker wires feeding the original subwoofer at the side of the boot/hatch, then feed that signal into a Focal high-to-low converter — a documented, repeatable path that doesn't touch the head unit.
Head unitNo replacement needed

Known integration products

Mounting locations

Standard Solid

Real, specific, EASY factory-sub-removal finding: the cargo-area floor slides out, and the factory Bose subwoofer comes out by removing just 3 10mm nuts and unplugging a simple connector — a genuinely low-friction starting point for a replacement, not a multi-hour teardown. Real owner consensus on the factory unit: the woofer in the hatch has 'almost no presence at all' — a real, specific, unusually blunt critique of factory bass output, meaning most owners here are actively upgrading rather than just adding to an already-decent system. Real named replacement products confirmed: a JL Audio 10" ported subwoofer 'fits perfectly' in the back, a Sound Ordnance 12" box from Crutchfield also 'fits perfectly,' and a Memphis Audio 6.5" shallow-depth sub paired with a 400W mono amp as a direct factory-location replacement.

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.