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Focal's Polyglass subwoofer uses precision craftmanship and advanced materials to create a big bass impression. Focal creates the Polyglass cone by depositing a layer of hollow glass microbeads over a layer of cellulose. This unique material combines the warm sound of cellulose with the incredible strength of glass, for a cone that responds rapidly with low resonance. The exceptionally resilient zinc alloy basket teams up with the Polyglass cone, butyl rubber surround, and an advanced motor structure to deliver uncolored bass that'll please the discerning ear.

The 21 V2 8" subwoofer handles up to 200 watts RMS, and Focal optimizes this sub to work in sealed enclosures for the best sonic results. Complete your system with a compatible amp and wiring to experience Focal's bass finesse.

Priced per speaker

Product Highlights:

  • 8" 4-ohm subwoofer
  • Polyglass cone with butyl rubber surround
  • zamak (zinc alloy) basket
  • power range: 50-200 watts RMS
  • peak power handling: 500 watts
  • frequency response: 40-500 Hz
  • sensitivity: 81.21 dB
  • top-mount depth: 4-1/2"
  • sealed box volume: 0.35-0.71 cubic feet
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

Focal Polyglass 21 V2 Reviews

Hands-on research

What's in the box?

Download owner's manual

  • 8" SVC 4-ohm woofer
  • 6 Hex-head mounting bolts
  • 6 Nuts
  • Self-adhesive foam gasket
  • User Manual (Eng/Fre)
  • Serial number card
  • FOCAL logo sticker
  • "Remove Before Using" note (attached to speaker terminals of woofer)

Product Research

Enclosure Compatibility


Polyglass Cone: The FOCAL Polyglass 21V2 features an 8" polyglass cone woofer for a wide, dynamic frequency response of 40-500Hz that offers neutral, coloration free sound. The uniform deposit of hollow-glass microballs over the entire cellulose pulp cone greatly increases its rigidity without adding significant weight, so you get a woofer that is durable, yet efficient, and sounds great.

NBR Surround: The FOCAL Polyglass 21V2 features a NBR (Nitrile Butyl Rubber) surround for long excursion, deep bass, and added durability to promote long life.

2" Voice-Coil: The Polyglass 21V2 woofer features a two layer, 2" diameter, single 4-ohm, voice-coil with a large copper wire on an aluminum support for higher power handling capabilities up to 200 watt (RMS) and 400 watt (Peak).

Louvered Cooling System: The Polyglass 21V2's Louvered Cooling System is self-regulated ventilation system which increases air cooling, prevents heat build-up, and provides optimized reliability with performance consistency.

120mm Magnet: The Polyglass 21V2 woofer features a 120mm (4.725") ferrite magnet for higher sensitivity up to 85dB (2.83V/1m).

Die Cast Chassis: The FOCAL Polyglass 21V2 features a die-cast Zamak chassis which is a rigid, non-magnetic, and non-resonant frame that provides a strong, reliable structure for the woofer.

Spring-Posts: The FOCAL 8" woofer is equipped with a pair of nickel-plated spring-post speaker terminals for easy connection up to 10AWG wire.

Foam Gasket: The Polyglass 21V2 comes supplied with a self-adhesive foam gasket mounting-ring for better chassis damping and to prevent air leakage.

Enclosure Compatibility

Recommended Sealed Box Volume: The FOCAL Polyglass 21V2 is designed to be installed in a sealed box with a volume between 0.42 cu/ft to 0.71 cu/ft. FOCAL recommends a sealed enclosure made out of 3/4" MDF with an internal volume of 0.53 cu/ft.

Sealed Enclosure Specifications (using 3/4" MDF construction)

Internal Volume 0.42cu/ft. 0.53 cu/ft. 0.71 cu/ft.
Dimensions Width: 13.375"
Height: 10.25"
Depth1: 10.25"
Depth2: 7.0625"
Width: 14.1875"
Height: 11.0"
Depth1: 11.0"
Depth2: 7.0625"
Width: 16.125"
Height: 11.75"
Depth1: 16.125"
Depth2: 7.0625"
Bass Type Fast and tight bass Punch and dynamic bass Deep and articulate bass

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Product reviews from the Crutchfield Labs

Video: Introduction to Focal car audio
by Zak Billmeier, Ken Nail

Crutchfield's car audio experts Ken and Zak present an overview of Focal car audio products. Focal is a leading name in high-quality sound and Crutchfield is proud to have them in our lineup.

What are the Labs?