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Diamond Audio HP12

HEX PRO Series 12" subwoofer with dual 2-ohm voice coils

Item # 114HP12

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Our take on the Diamond Audio HP12

Diamond Audio's statement subwoofer

You're passionate about music — and sometimes it takes a sub of almost mythic proportions to get it right. Diamond Audio designed this monumental HEX PRO Series HP12 12" subwoofer for dead-on, accurate bass and extreme performance.


Hexagonal honeycomb woofer

cone material

Proprietary honeycomb cone

This HEX PRO Series 12" sub features a unique honeycomb core, sandwiched between two thermally bonded layers of Kevlar, the same material used to make bulletproof vests. The resulting composite is exceptionally rigid, and also close to 70% lighter than conventional paper or polymer woofers. This featherlight cone can reproduce bass and midbass frequencies in your music with pinpoint accuracy.

Ultra-efficient motor assembly

cutaway shot

Neodymium magnet mounted
inside the voice coil

Engineers at Diamond Audio know that heat stresses a subwoofer, so they use several techniques to remove heat from the motor structure. The HEX Pro sub houses a high-temperature neodymium magnet inside its 3-1/2" voice coils, where aluminum frames act as a heat sink to draw damaging heat away from the magnet. A special thermal paste fills in the space between the voice coil and surrounding aluminum to insure optimal heat transfer.


Heat dissipating aluminum dustcap

The aluminum basket shunts off radiated heat quickly and efficiently. For even more relief from heat, an aluminum dust cap directs heat upwards and outwards, so it doesn't end up trapped in your subwoofer enclosure. A cool-running motor assembly means you'll get the cleanest, strongest performance from this woofer.

Non-resonant aluminum basket

Radial venting

Radial venting
on the cast aluminum frame

The cast aluminum basket gives this sub the stable foundation it needs to deliver faithful, uncolored bass for the lifetime of your system. Diamond Audio's proprietary O2 casting technique creates a denser, less porous basket that virtually eliminates unwanted resonance, so your favorite music sounds just as the artist intended.

Product Highlights:

  • 12" subwoofer with dual 2-ohm voice coils
  • Kevlar composite hexagonal honeycomb cone
  • nitrile butadine rubber surround
  • cast aluminum basket
  • power range: 80-800 watts RMS (1600 watts peak power)
  • frequency response: 20-250 Hz
  • sensitivity: 85.4 dB
  • top-mount depth: 8"
  • sealed box volume: 1.0 cubic feet
  • ported box volume: 1.75 cubic feet
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • 12" Dual 2-ohm voice coil subwoofer
  • Rubber trim-ring (installed)
  • 3mm Allen wrench
  • Eight 1-1/8" Self-tapping screws
  • Installation manual
  • Cardboard template

Hands-on research

Product Research

Enclosure Compatibility


Dual 2Ω Voice Coils: The HP12 features dual 2Ω voice coils. When the voice coils are wired in parallel, the woofer presents a 1Ω load; when wired in series, the woofer presents a 4Ω load.

TDX Technology: Diamond Audio's Thermal-Dyne eXtreme (TDX) is a system designed to eliminate the detrimental effects of heat on a speaker. The motor structure uses a Neodymium magnet mounted inside the voice coil; the geometry, venting, and material has been optimized to improve heat dissipation. The cast aluminum frame acts as a heat sink for the encapsulated motor structure. A special thermal paste is used between the motor case and aluminum frame to insure maximum heat transfer. The aluminum dust cap also acts as a heat sink for the voice coil.

NBR Surround: The woofer features a Nitrile Butadiene Rubber (NBR) surround, a synthetic rubber that stands up to the harsh automotive environment.

Set-Screw Terminals: The set-screw terminals will accept bare wire up to 8-gauge. A 3mm Allen wrench is included to tighten/loosen the terminals.

Concealing Ring: The included rubber trim-ring provides a mounting gasket and covers the mounting screws, giving the subwoofer a finished look.

Enclosure Compatibility

Sealed Enclosure: Two recommended sealed box volumes are listed in the manual; 1.0 cubic feet is given as the optimum size, and 2.0 cubic feet is labeled as a large enclosure.

Vented Enclosure: The recommended vented box volume is 1.75 cubic feet with a 4" diameter, 16" long port; resulting in a tuning frequency of 35 Hz. A 30 Hz sub-sonic filter is recommended for vented enclosures.

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.