Fi Subwoofers

Graphic featuring two car subwoofers, a logo for FTX Subwoofers, and text indicating they are made in the USA, with an American flag.

– American-Made Bass Authority

Fi Subwoofers are handcrafted in Las Vegas, Nevada, built to order for serious bass enthusiasts and competitors alike. Whether your goal is a clean, responsive daily driver or a world-class SPL build, Fi offers a subwoofer lineup with precision engineering, massive power handling, and full customization options.

A large speaker driver with a black metal frame, cone, and voice coil.

Alpha Series

  • RMS Power: 1000W

  • Xmax: 17 mm

  • Sizes: 10", 12", 15"

  • Highlights: Perfect balance of output and musicality for daily systems. Clean, deep bass without extreme power demands.

  • Best For: Upgrading from factory systems or adding solid bass without going into extreme SPL territory.

A close-up of a black speaker with a circular structure, featuring a basket grille and a cone, viewed from below.

Xv4 Series

  • RMS Power: 1500W

  • Xmax: 27 mm

  • Sizes: 10", 12", 15"

  • Highlights: Higher excursion and deeper low-frequency response for bass lovers who want a major upgrade in power and performance.

  • Best For: Enthusiasts wanting a daily system that hits harder while staying musical.

A close-up of a loudspeaker or subwoofer, showing the speaker cone, spider, and basket structure.

HC Series – Ferrite Motor

  • RMS Power: 2500W

  • Xmax: 34 mm

  • Sizes: 12", 15", 18"

  • Key Features:

    • Triple-stack ferrite magnet motor

    • Three-stage aluminum cooling system

    • Heavy-duty aluminum basket

    • Reinforced kraft pulp cone with dual-layer wide foam surround

    • 144-count tinsel leads sewn into spiders

    • Gloss carbon dustcap

  • Best For: High-output daily or competition systems that demand control, cooling, and reliability.

A black and gray suspension coilover with a US flag and snake emblem on the top, designed for automotive performance.

MT Series – Ferrite Motor

  • RMS Power: 4500W

  • Xmax: 33 mm

  • Sizes: 12", 15", 18"

  • Key Features:

    • Massive 4" voice coil

    • Triple-stack Y35 ferrite magnets

    • Two-stage aluminum cooling:

      1. Pole sleeve for heat transfer & reduced inductance

      2. Aluminum cap for additional airflow and thermal stability

    • Heavy 5-spider suspension

    • Optimized surround geometry for maximum SPL per mm of excursion

  • Best For: Extreme SPL builds and competition systems needing massive power and thermal durability.

A high-quality car subwoofer speaker with a black cone and yellow coil inside a black frame.

Neodymium Series – 3″ Coil (Neo 3.X)

  • Xmax: 34 mm

  • Sizes: 12", 15", 18"

  • Power Handling:

    • Neo 3.5 – 1750 W (2-spider, upgradeable to 3)

    • Neo 3.7 – 2500 W (3-spider, upgradeable to 4+)

    • Neo 3.9 – 2500 W+ (4-spider, upgradeable to 5–6)

  • Key Features:

    • Lightweight neodymium motor for higher efficiency

    • 3-stage cooling system with pole sleeve, domed compression cap, and finned extrusion

    • Push-terminal and bolted block connections

  • Best For: High-performance daily drivers to competition SPL builds with a focus on weight savings.

A subwoofer speaker with a black cone, yellow coil, and dual port design, featuring an American flag and star logo on the front.

Neodymium Series – 4″ Coil (Neo 4.X)

  • Xmax: 33 mm

  • Sizes: 12", 15", 18", select models in 21"

  • Power Handling: ~3500–4500 W

  • Models:

    • Neo 4.7 – ~3500 W, 3-spider

    • Neo 4.9 – 3500–4500 W, up to 4-spider

    • Neo 4.11 – ≥3500 W, up to 4-spider

  • Key Features:

    • 3-stage aluminum cooling system for maximum thermal stability

    • Push-terminal and bolted block connections

    • High-strength neodymium motor for SPL and high-power daily use

  • Best For: Competition systems needing extreme power handling with reduced weight.

Comparison chart of subwoofer series including Alpha, Xv4, HC, MT, Neo 3.X, and Neo 4.X, with details on RMS power, Xmax, sizes, motor type, and best use cases.

Quick Comparison Table

Why Fi Subwoofers?

  • Made in the USA – Built to order in Las Vegas, NV

  • Fully Customizable – Coils, cooling, suspension, dustcaps, and more

  • Competition Proven – Trusted in SPL lanes and by daily bass lovers worldwide

  • Thermal & Mechanical Reliability – Advanced cooling and reinforced suspension designs

📞 Contact Advanced Car Audio Solutions to order your custom-built Fi Subwoofer, get enclosure recommendations, and experience
true American-Made Bass Authority that is made not bought.