Copy of Stage 3 ported for FI BTL N3 18"

Carpet color: Charcoal
Sale price$249.88
In stock


Stage 3 - XTREME Performance Series Enclosure

There are many subwoofer enclosures on the market, but there is only one Sonix Enclosure. With its airtight design, blind dado assembly, internal bracing system, 45° supports, rounded corners and rear flared port this enclosure will surely leave you and your car shaking.

The Stage 3 comes with a wide range of features which where designed to get the most out off your subwoofer.

  • 1 3/4" front baffle which provides an exceptionally strong mounting surface for the subwoofer.
  • 45° supports to smooth out airflow and reduce turbulence.
  • Custom vertical bracing system (VBS) to prevent enclosure distortion and wall flexion.
  • Rounded internal and external corners to help reduce the diffraction of sound.
  • Gold plated terminal cups to increase electrical conductivity and reduce harmonic distortion.
  • Click HERE to see all the Stage 3 details

Each enclosure is carefully machined and assembled to meet the demands of high wattage subwoofers. Every part in the enclosure is cut by a computer numeric controlled (CNC) router under the guidance of a computer aided machining (CAM) software.


  • Compatible subwoofer : FI BTL N3 18"
  • Stage : 3
  • Version : V1
  • Type : Ported
  • Size (Width x Height x Depth) : 39.500 x 20.000 x 20.000 in.
  • Volume (net internal) : 5.5 ft³
  • Mounting diameter : Subwoofer Specific
  • Tuning frequency (Fb) : 31.95 Hz.
  • Port width : 3.75 in.
  • Wall thickness : 0.75 in.
  • Front baffle : 1.75 in.
  • Weight : 78 lbs
  • Terminal cups : One (1) 24 kt. Gold plated
  • Finish : Carpet

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