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Harmony Audio HA-ML181 Monolith 18 Competition Sub 3500W Dual 1 Ohm Subwoofer

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Harmony Audio HA-ML181 Monolith 18" Competition Sub 3500W Dual 1 Ohm Subwoofer
Harmony Audio HA-ML181 Monolith 18" Competition Sub 3500W Dual 1 Ohm Subwoofer

Leading the way

Why do all Harmony Audio subs feature interwoven tinsel leads? The answer is simple we demand nothing but the best. A tinsel lead is the small wire that connects the voice coil to the input terminal and if you look at most other subs its positioned so when the subwoofer is playing the cone will actually slap into the leads creating a pop noise when playing. The advantage to an interwoven tinsel leads is both increased durability and performance which is what Harmony Audio is all about.

Keeping things cool

The greatest enemy of a car audio subwoofer is heat which needs to be quickly dissipated for a sub perform correctly and is crucial to prolong the life of the subwoofer. Harmony Audio Rhythm, Alloy, Carbon & Monolith series subs feature large slotted vents directly under the spider which allows cool air to quickly reach all the sensitive components. The Flatline series features a unique fin shaped heatsink that transfers heat away from the voice coil.

Connecting it all together

Cutting corners is not the Harmony Audio way and while other manufacturers may be cutting out features to save a penny we are focused on producing a superior performing subwoofer. Take the wire terminal for instance probably one of the most important features of the sub which is what handles the power transfer from your amp to the sub. Many other brands now use a cheap spade terminal that takes longer to install and who knows if it will even stay connected once installed. All Harmony Audio subs feature a spring loaded push terminal that will accept direct speaker wire ensuring the ultimate connection and power transfer.


  • 18" Monolith Series Car Subwoofer
  • Power Handling:
    • Peak: 3500 watts
    • RMS: 1750 watts
  • Sensitivity: 88.4dB
  • Frequency Response: 30Hz-300Hz
  • Mounting Depth: 12"
  • Mounting Cutout Diameter: 16-13/16"
  • Min Sealed Box Volume (Cubic Feet): 3.88
  • Max Sealed Box Volume (Cubic Feet): 7.24
  • Min Vented Box Volume (Cubic Feet): 5.65
  • Max Vented Box Volume (Cubic Feet): 7.77
  • Magnet Weight: 306 Ounces
  • 3" CCAW Voice Coil
  • Dual 1 Ohm


  • Competition Grade Paper Cone
  • Stitched High Roll Foam Surround
  • Tinsel Leads Woven into Spider
  • Die-Cast Aluminum Basket
  • High Flux Ferrite Magnet

Detailed Specifications:

  • Voice Coil Diameter: 76.5mm
  • Voice Coil Height: 64.7mm
  • HE Magnetic Gap Height: 20mm
  • Voice Coil Bobbin: Black Aluminum
  • Xmax: 22.35mm
  • Magnet Layers: 8
  • Cms (Suspension Compliance): 0.043
  • Qms (Mechanical Q Factor): 6.83
  • Qes (Electrical Q Factor): 0.73
  • Qts (Total Q Factor): 0.66
  • Mms (Moving Mass): 500.5
  • Vas (Equivalent Volume of Compliance): 83.7 L
  • Rs (Resonant Frequency): 33 Hz
  • SD (Effective Piston Area): 1164.1 cm2
This item is New
1 Year Manufacturer's Warranty
Proposition 65 Warning for California Consumers

WARNING: This product can expose you to chemicals which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to

Ratings and Reviews


1 product ratings

Good subs

Sep 28, 2023

Great subs worth the money and good quality

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Return Policy
You may return this item in its original condition within 30-Days for a refund, minus a 20% restocking fee, and minus any shipping charges we paid to get the item to you.