4in Subwoofer Voice Coil D2 Ohm - Black Aluminum Former

In this review the 4in Subwoofer Voice Coil D2 Ohm from Springfield Speaker is evaluated for installers and hobbyists who need a robust, custom replacement voice coil. The bottom line: this is a purpose-built, high-RMS voice coil that excels where power handling and fit are the priority. Our review found the black anodized aluminum former and flat aluminum windings deliver a compact, heat-tolerant package suited to heavy-duty subwoofer builds, and the 3.965in inner diameter is the key spec to check against your driver's requirements.

Key Features

• Custom-made fit: Built specifically for applications that require a 3.965in inner diameter, reducing the need for modification during installation.
• Black anodized aluminum former: Provides corrosion resistance and a rigid, lightweight core that helps maintain coil shape under heat and mechanical stress.
• Flat aluminum windings: Improve thermal transfer and allow tighter winding density for reliable operation at high power.
• High RMS power handling: Rated for 1800W+ RMS, making it suitable for demanding subwoofer setups and long-term heavy use.
• D2 impedance: The D2 2 ohm configuration is compatible with many powerful amplifier setups commonly used in home and car subwoofer systems.

Who It's For

This voice coil is aimed at audio technicians, DIY speaker rebuilders, and enthusiasts who need a high-power replacement coil with a precise 3.965in inner diameter. It works well for custom subwoofer repairs where the original coil is damaged or when building a new driver that calls for a compact, power-dense coil.

Those who should look elsewhere include buyers seeking an OEM direct-replacement guaranteed to match a specific factory part number, or users who need a coil with different impedance or a larger diameter. Also, people who prefer copper windings for different electrical characteristics may prefer other options.

Pros & Cons

Pros

• Excellent heat tolerance from the black anodized aluminum former and flat aluminum windings for sustained high-power use.
• Custom 3.965in I.D. fit minimizes modification time and ensures a precise installation in compatible drivers.
• Very high RMS power handling of 1800W+ makes it appropriate for demanding subwoofer applications.

Cons

• Not an OEM part, so exact interchangeability with factory coils is not guaranteed and fit should be verified before purchase.

Specifications

Product type	4in subwoofer voice coil
Inner diameter (I.D.)	3.965in
Former material	Black anodized aluminum
Winding type	Flat aluminum windings
Power handling	1800W+ RMS
Impedance	D2 2 ohm
Compatibility	Custom-made for applications matching above specs

Our Verdict

The Springfield Speaker 4in Subwoofer Voice Coil is a practical choice for anyone building or repairing high-power subs who needs a tight 3.965in I.D. and robust thermal performance. It delivers excellent value where power handling and a durable aluminum former matter, but installers should confirm fit since it is not an OEM direct-replacement.

Frequently Asked Questions

Is this an OEM replacement?
This is a custom-made coil, not an OEM part, so buyers should verify dimensions and fit against their driver.

What size is the inner diameter?
The coil has a 3.965in inner diameter designed to fit drivers requiring that specific I.D.

How much power can it handle?
The coil is rated for 1800W+ RMS and uses flat aluminum windings and a black anodized aluminum former for improved heat handling.