Subwoofer Amplifier Calculator

Use this tool to match amplifier/amp specifications with your subwoofer. It can be used to select an amplifier for an existing set of subs or an entire system.

How to use the calculator

  • Enter the impedance in ohm (Ω) and the wattage (W) of each sub.
  • Select the configuration – Series or Parallel.
  • The tool will provide
    • Total Effective Impedance of the subs
    • Total Subwoofer Wattage
    • Required Amplifier Wattage range (min and max)
  • Refer to the amplifier data sheet to ensure that it is able to provide the RMS (root-mean-square) power at the specified impedance level.

Example Calculation

Let’s use the following subwoofer from Sklar as an example. It has an RMS power rating of 1000 W and impedance of 2 ohm.

Skar Audio DDX-12 D2 12" 1500 Watt Max Power Dual 2 Ohm Car Subwoofer

This is a Dual Voltage Coil subwoofer. Depending on how it is wired (see the picture below), the effective impedance is either 1 ohm or 4 ohm.

Assume it’s wired to give an effective impedance of 4 ohm, and two of these are used in parallel. In this case, using the calculator, the total effective resistance is 2 Ω and the recommended amplifier wattage is between 1800 W and 2400 W.

The highlighted amplifier RP-3500.1D would be the most appropriate selection in this case. The specification of this amp is 2300 W at 2 Ω.

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