How to match Car Subwoofer and Amplifier

Main Points to consider when matching Car Subwoofer and Amplifier

Are you wondering how to match a car subwoofer and amplifier? Look no further because this blog will answer all your questions. There are three main points to consider when matching a subwoofer and an amplifier:

  1. RMS Power Rating
  2. Impedance
  3. Type of Amp

Assuming you follow the instructions listed in this blog you will never again call into our customer service department with a question regarding which which amp matches your subwoofer. Their number is (661)-257-9993 just in case you need help with something else.

RMS Power Rating

The RMS power is the measure of continuous power the subwoofer can accept. This is the amount of watts the subwoofer can dissipate in the form of heat and vibration without damaging the voice coil. Although max power might be a more appealing number than RMS power, this only represents the subwoofer’s capability of handling quick bursts of power rather than sustained power. Always utilize the RMS power rating.

RMS vs Peak Power

If you are wiring two subwoofers to an amplifier, you must combine the RMS power rating of both the woofers to determine the power rating of the amp. For example two NVX VSW124v2 12″ subwoofers have 600w RMS each; 1,200w combined. What this means is that you’ll need an amplifier with a power rating between 1,080 and 1,440 watts. The perfect match is the NVX JAD1200.1 monoblock amplifier. It’s as if NVX planned these products to be used together!

Here is the calculation I used to find the power range of the amplifier:

Power range formula

Take the total watts and multiple it by .9 and by 1.2. This will give you the power range of your amplifier. This formula can be applied to your system and has been confirmed by the experts. It is encouraged you get an amplifier with extra power because this gives you more reserved power also known as headroom. This reduces heat exposure which is detrimental to your amp’s health. If you underpower your amplifier, your subs will output distortion causing excessive heat on the voice coil.

2. Impedance

Definition: The electrical resistance of a speaker restricting the flow of electricity, measured in ohms.

Impedance directly affects the load of the amplifier not the power requirement of the subwoofer. So when you wire your subs at 4 ohms versus 2 ohms, there will be a significant difference in power output. For example the Boss R1100M runs at 550w at 4 ohms or 1,100w at 2 ohms. But this amplifier is unable to accept a 1 ohm load because the amp will immediately go into protect mode or run excessively hot.

Impedance Diagram

Never go against the specifications the manufacturer has listed. For extra help use our Subwoofer Wiring DiagramThis is a comprehensive tool designed for almost any system!

3. Amplifier

A car amplifier ranges from 1-6 channels. A monoblock amplifier is the best choice for powering subwoofers because a monoblock amp is designed to output tons of power at low impedance. You can use a 2 or 4 channel amp but this limits your power output and impedance. When bridging channels you combine the output of the 2 channels and suddenly 4 channels becomes 2 channels and 2 channels becomes 1 channel. Note that a 2 or 4 channel amp bridged usually cannot accept a load lower than 4 ohms.

NVX JAD1200.1

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Monoblock amps can power as many subs as it wants as long as the minimum impedance is not exceeded and the output power matches.

  • When purchasing an amplifier ONLY buy products that are CEA compliant.
  • If you don’t play your music at high volumes and your car is not massive, than a 300 watt sub will satisfy your needs assuming you have a compatible amplifier.

4. Sonic Secret

The enclosure plays a huge role in the sound quality and output of your system. Note that ported enclosures require a subsonic filter and a sealed enclosure benefits from a more powerful amplifier. Never cheap out on the enclosure build, your system will suffer.

Born in a subwoofer box, music has always been my passion. At the proud age of 9 I began driving. The two eventually met and led to my career at Sonic Electronix.

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