2017-2022 Ford F-250 / F-350 Super Duty 4th Gen Super Duty (P558) — 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: Regular Cab, SuperCab, Crew Cab

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.

Crew Cab Likely

Locationunderseat, crew cab — shares geometry with F-150 SuperCrew per confirmed cross-platform commercial products
Outer bounding boxGoose Gear seat-delete data (above-platform storage spec): 28"W x 18"D x 22"H recommended max — confirms a real factory storage space exists below the rear seats with hatch access, same pattern as F-150
Known obstructionsNone specifically documented beyond what's already reflected in the audio-specific commercial box specs (7-1/8" cutout, 1.12 ft3 dual-8" sealed)
Usable volume estimate1.12 ft³

Starting points

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

Budget

Subwoofers2x8" sealed, 1.12 ft3 total
Box typesealed
Locationunder rear seat

Enthusiast

Subwoofers2x10" ported (real example: Skar Audio dual-10")
Box typeported
Locationunder rear seat

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 sizenot independently confirmed by exact diameter — real, named genuine OEM front door speaker part confirmed: LC3T-18808-BA (2021-2023). REAL, GENUINELY NOTABLE ARCHITECTURE FOUND: on the B&O system, this is confirmed as a real 'Front Door Speaker/Tweeter Install' (per a dedicated install video) — meaning front door service involves BOTH a woofer and a tweeter together, not a single coaxial.
Adapter bracket neededunconfirmed
TweeterPillar (A-pillar) — real, confirmed, distinct architectural detail: the pillar tweeters are powered DIRECTLY by the head unit, NOT through the B&O amplifier — a real, specific electrical fact worth knowing before assuming a generic B&O-amp tap covers the tweeters too. Real, practical wiring note: aftermarket upgrades require running new speaker wire from the component crossovers to the pillar tweeters.

Rear doors Solid

Factory speaker sizenot independently confirmed by exact diameter — real, named genuine OEM B&O rear door speaker part confirmed: JL3T-18808-RB (2017-2022).
Adapter bracket neededunconfirmed
Tweetern/a — tweeter (pillar-mounted) is a front-only component, not doubled to rear doors

Factory audio integration

Factory amp / premium audioReal, now includes a year split within this entry's span, not just architecture. 2017-2018: still the prior-generation Sony system (a 2017 F-250 King Ranch is confirmed Sony, not B&O) — this entry's B&O findings do NOT apply to these two model years. 2019-2022: Ford introduced B&O Play, gated to Lariat and higher trims, 10 speakers, up to 1,000W amplified. 2022 specifically documented at 740W across an 8-channel A2B amplifier — a real spec change within the B&O era, not just a rebadge. Pillar tweeters are powered DIRECTLY by the head unit rather than through the B&O amplifier — a genuinely important electrical detail distinguishing this from a simpler 'everything through one amp' assumption. XL/XLT trim status (below Lariat) not independently confirmed either way.
Adding subs without a head-unit swapConfirmed straightforward — same cross-platform product ecosystem as the F-150
Head unitNo replacement needed

Known integration products

Mounting locations

Crew Cab Solid

Notable cross-platform finding: DS18's dual-10" loaded enclosure is sold as fitting BOTH 2009+ F-150 Crew Cab AND 2017-2024 Super Duty Crew Cab — same underseat geometry across Ford's light-duty and heavy-duty crew cab lines. JL Audio's Stealthbox 13TW5v2 is similarly cross-listed for both. Real specific spec found: 8" dual sealed box, 7-1/8" cutout diameter, 1.12 ft3 total (0.56 ft3 per sub).

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.