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Looking for loud bass? JBL built this MS Series MS-12SD4 12" subwoofer extra tough, with features like a vented cast aluminum frame and stitched fabric surround that help this sub hit hard and last a long time. This sub works equally well in both sealed and ported enclosures, so you can achieve virtually any bass tone you want, from punishing to mellow.

Versatile and powerful
The dual voice coil (DVC) design gives you more flexibility in matching your sub system's total impedance to your amplifier, in order to get maximum efficiency and full power. And speaking of power, this sub takes up to 900 watts RMS, for performance that'll let you really feel your music's pounding beat.

Product Highlights:

  • 12" subwoofer with dual 4-ohm voice coils
  • polypropylene cone with stitched tri-laminate fabric surround
  • vented cast aluminum frame
  • power range: 50-900 watts RMS
  • peak power handling: 1800 watts
  • frequency response: 30-400 Hz
  • sensitivity: 87.0 dB
  • top-mount depth: 5-5/8"
  • sealed box volume: 0.95 cubic feet
  • ported box volume: 1.7 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.

JBL MS Series MS-12SD4 Reviews

Hands-on research

What's in the box?

Download owner's manual

  • 12" Dual 4 ohm voice coil subwoofer
  • Trim ring
  • Specification sheet
  • Warranty information

Product Research


Vented Cast Aluminum Basket: The vented cast aluminum basket effectively dissipates heat to minimize distortion due to power compression.

Dual 4-ohm Voice Coils: For increased system flexibility, the woofer has two 4-ohm voice coils. When the voice coils are wired in parallel the woofer presents a 2-ohm load; when wired in series, the woofer presents an 8-ohm load.

Sealed Box Volume: JBL recommends a 0.95 cubic foot sealed enclosure.

Ported Box Volume: JBL recommends a 1.7 cubic foot ported enclosure with one port, approximately 4" diameter x 8-5/8" long.

Power Handling: The woofer has two 4-ohm voice coils; each voice coil can handle 450 watts RMS (900 watts RMS total)/900 watts peak (1800 watts peak total).

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.