Performance Optimized Down Fire Sealed 10" Enclosure | Focal Flax Evo P 25 FSE Single 10" Sealed enclosure

Because Focal's suggested application table does not reconcile with the Thiele-Small parameters printed on the same sheet. Their table lists an F3 of 37.5 Hz at 12 liters and 34 Hz at 18 liters. Running their own published Qts of 0.78 and Vas of 25 liters through standard sealed box math at those volumes produces roughly 49 and 46 Hz instead.

The deciding factor is Focal's own frequency response graph, also printed on that sheet, which shows output rolling away below approximately 45 Hz. That measured curve agrees with the computed figures rather than with the application table. Two of Focal's three data sources agree, so we publish the computed number.

No. The P 25 FSE has a free-air Qts of 0.78, and system Qtc can never fall below the driver's Qts regardless of enclosure size. Even an infinite baffle would leave this driver above 0.78, so no sealed box reaches a textbook 0.707 alignment with it. At 0.80 cubic feet net the system sits at Qtc 1.131, which produces a modest lift near the corner frequency.

Building larger changes very little. A full cubic foot improves Qtc to 0.923 and F3 by roughly one hertz, which does not justify the additional cabinet height on a down fire enclosure designed to fit under a seat.

Flax is a natural fiber Focal uses in place of the polypropylene or treated paper common elsewhere in this category. The appeal is the combination of stiffness relative to mass and good internal damping, which helps a cone hold its shape under load without ringing. Focal has developed the material across their range for years and the Flax Evo layup is their current version of it.

On this driver it pairs with a rubber surround, a 38mm four-layer copper voice coil and a glass fiber former. Whether you can hear the cone material specifically is a fair question, but the engineering behind it is real rather than cosmetic.

Straightforward, because the P 25 FSE is a single voice coil driver at 4 ohms nominal. There is no series or parallel decision to make. The enclosure has one side-mounted Proline X terminal cup pre-wired in 12 gauge OFC, and the amplifier sees 4 ohms. Confirm your amplifier is comfortable at that load and set your gain for the 280 watt RMS rating.

Side mounted. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup regardless of alignment, whether standard, wedge, or down fire. On this cabinet that keeps the connection fully accessible with the enclosure in its installed position, since the baffle faces the floor. The cup is our Proline X ABS and carbon fiber composite unit, recessed, with stainless hardware, copper ring terminals, and pre-wired 12 gauge OFC.

Down Fire cabinets are built with square corners as a series standard. The 3 inch top down corner radius used on other Proline X alignments does not apply here. A down fire box is a low, wide platform that sits flat against a floor or under a seat, and square corners maximize usable internal volume for a given footprint while keeping the cabinet stable on its mounting surface.

V-groove and dado joinery, CNC-cut on ShopSabre routers from Langboard Elite MDF. Every panel joint is a machined interlocking groove that mechanically locks the panels before adhesive is applied, which is what keeps the cabinet airtight under sustained pressure cycling. The front baffle is a double layer at 1.5 inches, two bonded 3/4 inch sheets, standard across the Performance Optimized Series. Perimeter cross-bracing and pre-installed polyfill complete the build. Assembled and inspected in Tullahoma, Tennessee.

No. This listing is for the enclosure only. Bring your own Focal Flax Evo P 25 FSE. The cutout and mounting depth are direct fit.