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 Sedan
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | trunk, general |
|---|---|
| Outer bounding box | No independently measured raw cavity envelope found. Only SAE cargo-volume figures (14.2 cu ft standard / 11.1 cu ft eAssist) were confirmed, and SAE volume is a luggage-fit rating, not a usable rectangular envelope — do not surface it to a user as buildable box volume. |
| Known obstructions | Factory amplifier behind the PASSENGER-SIDE trunk panel, just forward of the wheel well, sitting behind a removable false wall — see audio_integration for the full access sequence. Passenger-side trunk latch trim panel. Spare tire well. On 2011 CXL cars specifically, a power block on the DRIVER'S side of the trunk. On eAssist cars additionally: the HV battery pack occupying the trunk-front bulkhead behind the rear seat, plus the package-tray cooling-air vent that must stay unobstructed. |
Suggested configurations for this vehicle, not prescriptions. Run the numbers in the Box Builder before you buy anything.
| Subwoofers | 1x10" powered/compact sealed unit fed by a speaker-level-to-line-level converter tapped at the rear deck speakers on Bose cars, or a standard LOC at the rear speaker wiring on base 7-speaker cars. |
|---|---|
| Box type | sealed or powered enclosure |
| Location | trunk, mounted clear of the passenger-side amp panel and — on 2011 CXL cars — clear of the driver's-side power block |
| Subwoofers | 1x12" sealed or 2x10" sealed, custom-built. No vehicle-specific molded Regal enclosure was found, so this is a custom-box car by default. The 14.2 cu ft trunk is slightly more generous than the LaCrosse sibling's 13.3. |
|---|---|
| Box type | sealed, custom |
| Location | trunk. On eAssist cars, do NOT plan a forward-firing box against the trunk front wall — the HV pack is there and the package-tray cooling vent above it must stay clear; fire rearward or upward and work inside the smaller 11.1 cu ft envelope. |
Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.
| Factory speaker size | 6.5" full-range, confirmed by two independent sources — a factory speaker size chart covering both the 2011-2014 and 2015-2017 halves of this generation, and a car-audio discussion describing the front doors as 6.5" components. Note this is a cleaner result than the LaCrosse companion entry, where the same size chart reports 6.75" and a forum source disagrees; here the two sources agree on 6.5". |
|---|---|
| Known obstructions | Not documented. Window regulator/motor clearance and factory harness connector type were not confirmed. |
| Adapter bracket needed | unconfirmed — likely, as with nearly all GM door openings, but no Regal-specific adapter product was confirmed (unlike the LaCrosse, where a real year-scoped adapter listing was found) |
| Tweeter | front door — the size chart places the tweeter in the front door on this generation, NOT in the A-pillar. Worth flagging because the LaCrosse sibling in this same database is confirmed A-pillar; the two Buick sedans do not share tweeter placement, so do not carry that finding across. |
| Factory speaker size | 6.5" full-range. Rear door speakers are present and replaceable across 2011-2017. |
|---|---|
| Known obstructions | Not documented. |
| Adapter bracket needed | unconfirmed |
| Tweeter | n/a — tweeters are front only |
| Factory amp / premium audio | optional-on-some-trims — Bose on premium trims. Documented speaker counts: 9 speakers on premium trims, 7 on base. THE FACTORY AMP LOCATION IS THE STRONGEST FINDING IN this entry and it is corroborated by two independent sources rather than one. Access sequence, as reported: open the trunk; on the PASSENGER SIDE, just forward of the wheel well, pop out two plastic push pins; remove the plastic trim piece carrying the trunk latch; then remove the false wall behind it — the amp is a large silver unit with three connectors. The second source independently describes the separate system amplifier as living in the trunk behind the passenger-side trunk panel, with all speakers powered from it. Two sources, same side, same panel — this one is solid by the standards of this guide. Additionally, on 2011 CXL cars a power block sits on the DRIVER'S side of the trunk and is usable as a power source, which is a real convenience and a real 'don't cut here' warning at the same time. |
|---|---|
| Adding subs without a head-unit swap | Yes. On premium/Bose cars the correct approach is a speaker-level-to-line-level converter rather than a conventional RCA line output converter, because GM Bose amplifiers take speaker-level input — tapping between the head unit and the Bose amp degrades the original signal, so tap at the rear deck speakers instead and mount the aftermarket amp in the trunk near them. On base non-premium cars a standard LOC tapped at the rear speaker wiring is sufficient. CAVEAT, stated plainly: the Bose speaker-level finding is GM-Bose-architecture guidance sourced from a GM Bose thread centered on a Chevrolet Malibu, not verified on a Regal specifically. No Regal-specific speaker wire colors were confirmed — unlike several Chevrolet entries, which do carry exact wire-color references. |
| Head unit | No replacement needed |
Standard (non-hybrid) cars: 14.2 cu ft SAE trunk volume, confirmed consistently across 2011, 2012, 2014, 2015, 2016 and 2017 model years by multiple independent spec aggregators — an unusually stable figure for a 7-year run, which raises confidence that the trunk was not meaningfully revised mid-generation. Slightly larger trunk than the LaCrosse sibling despite the smaller car. Rear seat fold and pass-through were not confirmed.
eAssist mild-hybrid cars only. 11.1 cu ft — a real ~3.1 cu ft loss versus the standard car, caused by the high-voltage battery pack mounted in the trunk in a compartment directly behind the rear seat. GM's own description of the reduction is explicit that trunk space is cut relative to the 2011 four-cylinder/six-speed car. Same thermal keep-out as the LaCrosse: the pack is cooled by an electric fan drawing air from a vent in the package tray behind the rear seat, so a build must not seal off or blanket the package-tray area. Treat this as a different cavity, not a smaller version of the same one.
Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.
Each link opens the tool with this vehicle already selected.
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.