How to connect a subwoofer to an old amplifier? (Important Facts & Tips)

As a music enthusiast, you understand the importance of quality audio devices. You crave the detailed low-end bass just as much as the mid and high notes. To solve your audio device’s low-end bass problem, you’ve decided to invest in a subwoofer. But now, you’re faced with the challenge of how to connect a subwoofer to an old amplifier.

Connecting your new subwoofer to your vintage amplifier can significantly enhance the sound quality of your audio system while saving you money. In this article, we present a comprehensive guide to help you connect your subwoofer to your vintage amplifier.

About the Stereo Subwoofer

Subwoofers are the key players in producing deep bass and sub-bass sounds. Regular and surround sound systems alone can’t provide the deep bass and sub-bass sound that echoes deep in your chest as your favorite music fills the room.

A subwoofer introduces a different level of deep bass and sub-bass that you could never have imagined existed. You know you’ve got real deep bass and sub-bass sound when your glass of water sitting on the table ripples, or you feel the vibration deep down your lungs, spine, and every other core part of your body. For more information on how subwoofers work, check out our article on how to make your own subwoofer cable.

The Function of a Subwoofer

A subwoofer serves several functions:

  • Produces High-quality Deep Bass: Subwoofers are known for producing deep bass and sub-bass sounds, also known as lower frequency sounds. While regular speakers can produce frequencies as low as 50Hz, subwoofers produce frequencies as low as 20Hz or lower, providing a deeper sound experience.
  • Reduces Distortion: Regular speakers can produce distortions when used to produce low-frequency sounds at increased volumes. A great subwoofer allows you to play low frequencies at an increased volume without distortions.
  • Division of Labor: A subwoofer can lighten the burden of smaller speakers in a full-range speaker set, allowing them to perform their original duty well.

For more on the benefits of subwoofers, see our guide on how to connect a car subwoofer to a soundbar.

Types of Subwoofers

Subwoofers come in two types: Passive Subwoofers and Active Subwoofers.

  • Passive Subwoofers: These subwoofers rely on external power sources and amplifiers to produce the deep bass and sub-bass sounds. They are ideal for spacious rooms and are often used in home theatre setups.
  • Active Subwoofers: Also known as powered subwoofers, these come with a power source and a built-in amplifier. They are suitable for a single subwoofer configuration in your home theatre but consume more power compared to passive subwoofers.

For more on the different types of subwoofers, check out our article on how to set up a power amp.

How to Connect a Subwoofer to an Old Amplifier

Before you start connecting your subwoofer to the old amplifier, ensure your subwoofer has high-level inputs and regular RCA ports. Also, check that your receiver can play both main and remote/speakers A and B output simultaneously.

For Active Subwoofers

  1. Connect the speaker set A port on your old amplifier to your regular speakers using high-quality speaker wires.
  2. Connect the set B speaker output to the high-level input on your subwoofer.

For Passive Subwoofers

  1. Connect your speaker cables from your amplifier to the subwoofer.
  2. Run another speaker cable from your subwoofer to connect to the two stereo speakers.

For more on connecting subwoofers, see our guide on how to connect studio monitors.

General Way to Connect an Amplifier and a Subwoofer

If your amplifier is relatively new, you can use either speaker cables or RCA cables to connect your amplifier to your subwoofer.

  • RCA Connectors: This method works best if your amplifier has an LFE subwoofer output. If not, you can use stereo RCA connectors. Plug your RCA cable into the “Line-in” port on your subwoofer, then run it into your amplifier.


A true audiophile knows that a full-range speaker isn’t complete without a subwoofer. Now that you know how to connect a subwoofer to an old amplifier, your music experience will never be the same. With either a passive or active subwoofer, you’ll not only hear every low-frequency detail, but you’ll also feel it. Subwoofers can redefine your low-frequency sound experience at all levels of sound. For more on enhancing your audio experience, check out our article on how to connect your new HDTV properly.

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