Refers to the diameter of the subwoofer, measured in inches.

This is the design of the subwoofer or the opening of the subwoofer enclosure. Each design has it's own benefits, whether it is a square, circle, or oval.

This is the color of the speaker's or subwoofer's cone.

Dual voice coil subs have more wiring flexibility than single voice coils subs; however, single voice coil subwoofers provide easier hookup options for wiring multiple subwoofers in parallel or series. You may also run a dual voice coil (DVC) sub in parallel, series, or combination. A quad voice coil has four voice coils and is equal to two dual voice coil subwoofers as far as wiring goes.

The load value (in ohms) that the speakers present to the amplifier per voice coil - the amount of resistance to the current flow. This is a key specification as subs wired in parallel or low impedances can create problems with your amplifier and potentially void all warranties. We encourage you to ask our support department prior to purchase if you do not understand which impedance level will suit you/your amp best.

Peak power handling refers to the amount of power a speaker can handle during a brief musical burst. The RMS power range figure is a much more reliable rating for determining the speaker's power requirements. The Peak power handling specification is typically rated per speaker unless otherwise noted.

The RMS power is the amount of power the speaker requires to operate safely and properly. RMS Power Handling refers to the amount of power a speaker can handle on a continuous basis. We recommend powering your speaker or subwoofer 75% - 90% of its recommended RMS rating. The RMS power handling specification is typically rated per speaker unless otherwise noted.

The woofer cone material is essential for efficient operation. Poly cones produce exceptional sound and are sturdy against various changes in temperature. Paper cones are very efficient, and when treated for moisture resistance, will perform at a high level. Poly refers to polypropylene: thermoplastic plastics or fibers that are polymers of propylene. IMPP refers to injection molded polypropylene, a commonly used process and material in speaker manufacture.

The flexible ring around the edge of the woofer cone. Surrounds are usually made of cloth, foam or rubber. Rubber and composites tend to last longer and hold up better in harsh environments.

This value indicates the minimum sealed box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.

This value indicates the maximum sealed box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.

This value indicates the minimum ported box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.

This value indicates the maximum ported box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.

An efficiency or sensitivity rating tells you how effectively a speaker converts power into sound. The higher the number, the more efficient the speaker and the louder it will play with the same input power. An efficient speaker helps you maximize your available power. Most sensitivity ratings measure the speaker's output with 1 watt of input, 1 meter from the speaker. Some speakers' sensitivity is measured with 2.83 volts of input, instead of 1 watt.

Efficiency (1W/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other subwoofers to determine which one is "louder".

The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).

Typically measured in millimeters, the Xmax value is the measure of a speaker cone's maximum excursion in one direction while maintaining a linear behavior.

The depth when installed on top of the mounting surface. Measured from the bottom of speaker(magnet) to the bottom of mounting holes on rim of speaker.(Most common application)

This means that the subwoofer/speaker is designed to be installed in areas that do not have a lot of space. Shallow mount subwoofers are typically found under a seat or behind the seat in some trucks.

Shallow mount speakers will typically have a mounting depth of less than 2".

Refers to the hole dimensions (in inches or millimeters) needed to mount the speaker.

This is the recommended type of enclosure that the subwoofer should be installed into. Some subwoofers are specially designed for particular enclosures.

Most subwoofers are able to accommodate a universal grille; however, some subs include a grille and others have a specific, optional grille available for purchase separately. If "yes", then the subwoofer includes a grille. If "optional (sold separately)" the matching grille will need to be purchased in addition to the sub.

Some higher end subwoofers have replaceable cone assemblies. In case of a blown woofer, a recone kit allows for a simple replacement, as opposed to purchasing an entire new subwoofer.