How to connect an amplifier to a passive subwoofer

The term passive subwoofer correctly implies that there are no internal amplifiers and therefore external ones would have to be connected. 

I primarily used subwoofers for low-frequency sounds and to enhance the bass quality of your speakers. 

The size of your room will determine the size of the subwoofer – the larger the room, the larger the subwoofer. 

Power ratings and ohm loading are some things to consider when choosing a suitable amplifier for your subwoofer.

Step 1- Connect the RCA cables

Cables will connect the subwoofer to the amplifier. The subwoofer output can be monaural or stereo. 

You can find them in the fundamental unit of your subwoofer (rear). With monaural output, you only need one cable for output.

 For stereo output, you will need two cables. The colors of the two cables will be different to make sure you connect them to the correct jacks.

Step 2 – Understand your subwoofer

Your subwoofer can be a single voice coil or a dual voice coil (popular in car audio systems). 

A Dual Voice Coil subwoofer offers multiple wiring options, such as parallel, serial, or independent. 

With a single voice coil, a single set of terminals would include positive (red) and negative (black), while the dual voice coil has two of these sets of terminals.

Step 3 – Connect to the amplifier

The biggest advantage of a passive subwoofer is that it gives you the option of working with different amplifiers according to your needs and required characteristics, which is not possible in active subwoofers. 

Make sure your amplifier is off before starting. Now connect the RCA cables already connected to the input jacks of the subwoofer to the amplifiers. 

I would label the amplifier connector LFE (low frequency effects) or subwoofer output.

 This is where the RCA cable connects. Note that we are only discussing how to connect a single subwoofer, but we can connect multiple subwoofers to one amplifier.

Step 4 – Connect the amplifier to the speakers

Finally, connect the amplifier to the speakers. On the back of your amplifier, you will find ‘main’ or ‘front’ speaker outputs. Connect two speaker cables to these outputs, one to each. 

The bare end will go directly to the speakers. Make sure the “left” output is connected to the left speaker and the “right” output goes to the right speaker of your stereo. 

There is often a definite polarity, in which case, make sure the positive terminal of the speaker goes into the positive end of the amplifier, and the negative terminal of the speaker goes into the negative end of the amplifier. 

Work with your receiver’s crossover / bass management settings for optimal sound and bass control. This will provide a complete surround sound system,


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