Ford B&O Subwoofer Harness - Fixes Factory Bass Roll-Off (2018-2026)

The only pre-tuned, plug-and-play subwoofer harness that fixes the factory bass roll-off on Ford B&O and B&O Unleashed systems. Add a real aftermarket subwoofer to your Ford and finally hear full bass at every volume level — hand-built and tuned in Nashville for your exact truck.

The problem, in one line

• Around volume level 14 (varies by trim), Ford's B&O DSP starts turning your bass down.
• Above volume 14, the DSP halves the voltage on the subwoofer channel depending on how much bass is in the song — your sub output becomes unpredictable.
• No external DSP, Zen, LC2, or generic LOC will fix this. The voltage halving happens inside the factory B&O amp before any of those components see the signal.
• Without the right harness, you end up chasing the subwoofer knob all drive. Reviewers call the result "muddy yet tinny."

Why our method works

We tested every integration option on the market. None held up, so we built our own. Instead of tapping the factory subwoofer output (where the roll-off happens), our harness taps two specific interior speakers whose signals stay clean at any volume, and routes them through a pre-programmed Kicker KeyLOC module.

Here's why that combination matters:

• Those interior speakers carry just enough low-frequency information to reconstruct a full subwoofer signal.
• B&O applies all-pass filters to interior speakers that introduce frequency-dependent phase shifts. A standard LOC sums left and right naively — which causes cancellation in the bass region where you need it most.
• The Kicker KeyLOC's signal processing corrects those phase shifts and combines the left and right channels (tuned differently on B&O) into a clean, phase-coherent subwoofer signal. Kicker's KeyLOC technology is patented; our vehicle-specific tunes are proprietary to Sounds Good Stereo.

Every Fix Roll-Off variant ships pre-programmed at our Nashville facility for your exact year, model, and factory system. Connect 12V power, ground, and remote turn-on, land the included RCAs on your amplifier, and you're done. No head-unit work. No wire cutting. No tuning guesswork.

What you're buying

• Fix Factory Bass Roll-Off variants ($290) — Custom SGS harness + pre-tuned Kicker KeyLOC module ($130 MSRP retail) + vehicle-specific tune + lifetime retune if you swap Fords. The professional answer. This is what we put in every Nashville build that uses an aftermarket subwoofer amp.
• Keep Factory Bass Roll-Off variants ($41–$61) — Just the plug-and-play passthrough harness. Bass plays as the factory system sends it: stable from volume 0–14, unpredictable above 14 as the factory DSP halves the subwoofer voltage depending on how much bass is in the song. No external DSP, Zen, LC2, or generic LOC will change that. Choose this variant if you specifically want the passthrough and accept the above-14 behavior.

How to pick your variant

The 3-step guided selector at the top of this page will walk you through it. Quick summary:

1. Identify your factory subwoofer shape. Remove the rear seat bottom (two 10mm bolts). Oval = 2021+ F-150, F-150 Unleashed, Super Duty 2020+, Ranger, Bronco, most newer B&O. Round = pre-2021 F-150, some Expeditions, Edge, Escape, Mustang, Mach-E. If you can't tell, text a photo to 615.610.1413 — we'll confirm in 60 seconds.
2. Decide on the roll-off fix. For nearly every build adding an aftermarket subwoofer amp, Fix Factory Bass Roll-Off is the right call.
3. Match output to your amp. Fix variants ship with a LOC and are always Low Level (RCA). Keep variants give you the factory signal as-is — pick High Level (RCA) for amps with built-in high-level / LOC inputs (JL Audio, Kicker, Arc, Mosconi, newer Alpine, newer Rockford), or High Level (Speaker Wire) for amps that require an external LC2i or similar LOC (older Alpine, AudioControl, older Rockford). You'll use our speaker-wire output into that external LOC.

Not 100% sure? Call or text 615.610.1413 before ordering. We'd rather spend five minutes on the phone than have you reinstall. This is by far the most-asked-about product on our site — every experienced tech on our team has it memorized.