Cut for Fi Car Audio Alpha, NEO and Xv4

Fi Car Audio Subwoofer Boxes and Enclosures

Sealed and ported enclosures cut for Fi Car Audio subwoofers, CNC-machined in Tullahoma, Tennessee.

Cut for Fi Car Audio Alpha, NEO and Xv4

Enclosures cut for Fi Car Audio subwoofers: the Alpha 12 and Alpha 15 in sealed wedge form, and the NEO 3.5, NEO 3.7 and Xv4 15 inch in Professional Series ported cabinets. Each one is built around a named driver, so the alignment matches the subwoofer you own.

9 enclosures cut for 5 Fi Car Audio subwoofer models, 12 to 15 inch, sealed and ported.

Cut, assembled and finished in Tullahoma, Tennessee, to the parameters Fi Car Audio publishes for each driver.

Driver parameters are taken from Fi Car Audio published data. We build enclosures to those figures; we do not currently stock Fi Car Audio drivers and make no claim to represent the brand.

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Fi Car Audio Subwoofer Box Directory by Model

We build sealed and ported enclosures for 5 Fi Car Audio subwoofer models, 12 to 15 inch, in wedge and standard styles from single and dual woofer cabinets. Open a model to see every box cut for it, with net volume, tuning and outside dimensions. Full specs and fitment notes are on each product page.

Fi Car Audio Alpha 12 2 boxes
BoxSeriesNet volumeTuningOutside dimensions
Wedge Sealed, SinglePerformance Optimized0.80 ft³Sealed18.66" W x 15" H x 13.03" D, tapering to 7.57"
Wedge Sealed, DualPerformance Optimized1.60 ft³Sealed32.00" W x 16" H x 13.46" D, tapering to 7.63"
Fi Car Audio Alpha 15 2 boxes
BoxSeriesNet volumeTuningOutside dimensions
Wedge Sealed, SinglePerformance Optimized2.54 ft³Sealed29.50" W x 18" H x 16.72" D, tapering to 10.17"
Wedge Sealed, DualPerformance Optimized3.60 ft³Sealed36.00" W x 18" H x 18.68" D, tapering to 12.13"
Fi Car Audio NEO 3.5 15 2 boxes
BoxSeriesNet volumeTuningOutside dimensions
Standard Ported, SingleProfessional2.98 ft³34.5 Hz36.00" W x 18.00" H x 17.50" D
Standard Ported, DualProfessional3.73 ft³29.0 Hz46.00" W x 18.00" H x 18.00" D
Fi Car Audio NEO 3.7 15 1 box
BoxSeriesNet volumeTuningOutside dimensions
Standard Ported, SingleProfessional3.04 ft³35.0 Hz36.00" W x 18.00" H x 18.00" D
Fi Car Audio Xv4 15 2 boxes
BoxSeriesNet volumeTuningOutside dimensions
Standard Ported, SingleProfessional2.17 ft³34.5 Hz36.00" W x 18.00" H x 14.00" D
Standard Ported, DualProfessional3.31 ft³35.0 Hz46.00" W x 18.00" H x 15.50" D

Two Kinds of Fi Cabinet

Fi Car Audio drivers split into two jobs on this page, and the cabinets follow.

Alpha, sealed wedges

Performance Optimized sealed wedges for the Alpha 12 and Alpha 15, single and dual. Cut to one driver on a 1.5 inch double baffle and shipped with polyfill installed. The compact choice for a daily driver.

NEO and Xv4, ported for output

Professional Series ported cabinets for the NEO 3.5 15, NEO 3.7 15 and Xv4 15, with dual versions for the NEO 3.5 and Xv4. These are larger cabinets for output, and they need the power to match. Tuning is stated on each listing.

Plan the Power and the Space

A 15 inch ported cabinet is a large box. Measure the opening with the trim in place and check the external dimensions on the product page before you order. Confirm your amplifier is stable at the final impedance your wiring produces, particularly on the dual cabinets.

How These Are Built

Langboard Elite MDF, CNC cut in Tullahoma, Tennessee, prewired to a Proline X ABS and carbon fiber terminal cup, and covered by a 2 year limited warranty on craftsmanship and materials.

Browse the wider range at the subwoofer box hub, or look at Performance Optimized enclosures, Professional Series enclosures and wedge enclosures.

See every brand we cut enclosures for on the subwoofer boxes by brand page.

How to Choose a Fi Car Audio Box

Start from the model number, not the size

Two Fi Car Audio drivers of the same diameter rarely want the same cabinet. Read the model on the magnet or the label, then open that model in the directory above. Every box listed under it was cut to that driver's published parameters.

Sealed or ported

Sealed cabinets are smaller, tighter and need less power, and every one ships with polyfill installed. Ported cabinets play louder around their tuning frequency, which on this page runs from 29 to 35 Hz, but take more space and more amplifier.

Single and dual

Multi-driver cabinets take two or more of the same model. Plan the wiring before you order and confirm your amplifier is stable at the final impedance it produces.

Pick the cabinet style that suits the vehicle

A wedge sits against the rear seat on a trunk or cargo floor and angles the driver up into the cabin. Professional Series cabinets are our ported builds for output.

Measure Before You Order

Outside dimensions on this page run from 18.66" W x 15" H x 13.03" D, tapering to 7.57" for the single wedge sealed cut for the Alpha 12, up to 46.00" W x 18.00" H x 18.00" D for the dual standard ported cut for the NEO 3.5 15. Every listing states its own figures, so check them against the space with the trim in place.

Wedges

Wedge depth is given at the base and at the top. Measure the floor depth with the seat back in the position you drive with, not folded forward.

Quick Reference: Fi Car Audio Coverage

12 inch: Alpha 12

15 inch: Alpha 15, NEO 3.5 15, NEO 3.7 15, Xv4 15

Different Fi Car Audio Driver?

If your model is not listed, tell us the driver and the space you have and we will tell you what we can build.

931-563-5151|contact@audiointensity.com

Fi Car Audio Subwoofer Box Questions

Which Fi Car Audio subwoofers do these boxes fit?

The Alpha 12, Alpha 15, NEO 3.5 15, NEO 3.7 15 and Xv4 15. Each listing names the exact driver it was cut for.

Why are the Alpha boxes sealed and the NEO boxes ported?

They are built for different jobs. The Alpha cabinets are compact sealed wedges for daily use. The NEO and Xv4 cabinets are Professional Series ported builds for output.

Do the sealed boxes come with polyfill?

Yes. Every sealed cabinet ships with polyfill installed. The ported cabinets ship without it.

Do I need anything else to install one?

An amplifier and wiring. These are passive enclosures with no amplification built in.

Subwoofer Boxes by Brand

Every box is cut to one driver's published specs. Pick the brand your subwoofer comes from.

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Amplifiers for the System

Power for Your Subwoofer System

Monoblock amplifiers matched to the power requirements of the drivers these enclosures are built for. Buy the enclosure, match the driver, pick the right amplifier.

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Last updated October 10, 2026