How To Connect A Subwoofer To An Old Amplifier? Top Full Guide

How To Connect A Subwoofer To An Old Amplifier? Top Full Guide

In this article, Hooke Audio offers advice on how to connect a subwoofer to an old amplifier. Subwoofers are devices that produce deep bass tones, while amplifiers handle volume control and other functions. It can be a difficult task to find an amplifier with an input jack to match up with the input jack of the subwoofer, but this blog post includes steps to overcome the problem. Let’s get started.

What is a Subwoofer?

Although it may seem strange, humans can hear the vibrations in the air at 20 Hz. This frequency can be divided into four subsections.

  • Low frequencies are between 20Hz and 100Hz.
  • 100Hz – 1kHz fall in the low- to mid-range.
  • High mid-range frequencies are 1kHz-10kHz.
  • High frequencies are 10kHz to 20kHz.

There are different types of speakers for each section that can produce the best sound. Subwoofers provide low-frequency sound. They can be used in a variety of ways depending on the purpose.

You probably know what subwoofers can do if you have ever seen a movie that uses them, especially if there are lots of shootouts or explosions.

Types of Subwoofers

There are two types of subs: passive and active.

The amplifier will not be used to power active subwoofers. They will need their own power supply. They only need the correct signal from the amplifier to get them working properly.

A passive subwoofer must be connected with the amplifier to power it, as you might have noticed. It’s only as good as the amplifier it is connected to. Stereo systems will typically have at least two channels.

Stereos that only have one channel are not ideal as they don’t allow for much bass. A subwoofer can reach the low notes of a song that speakers cannot.

Subwoofers are available in two types: front-firing with the main drive facing forward or down-firing. Subwoofers that are front-firing can be placed near the main speakers to enhance the sound they already emit. The front-firing subwoofers, especially for music, are preferable.

A ported subwoofer is one that has ports connecting to the circuits inside. It is a sealed subwoofer if it does not have ports. They are more affordable and provide better audio quality.

How Does A Subwoofer Work?

An amplifier amplifies the low-level input signal to drive the subwoofer’s voice coil with enough power and move the speaker cone. This produces sound. Deep bass is produced when the cone moves air within a specially-designed enclosure (speakers box).

These are for only bass frequencies and not for voice or any other musical instruments.

An amplifier is included in a powered subwoofer. It has a low-pass crossover that blocks higher sound frequencies to produce great bass.

Non-powered subwoofers: The problem is when you connect it to an amplifier’s or receiver’s outputs, without a crossover. It sounds horrible!

Do Subwoofers Work Better With Old Amps or Modern Receivers?

It might seem that modern subwoofers are best matched with the appropriate technologies. But, it is more complicated than that. A lot of factors will affect the sound quality of a subwoofer.

You should be able to connect a subwoofer to an amplifier you have lying around. You won’t get the perfect sound with every amp, however.

Vintage amps can be purchased at specialty shops. They will be more expensive than the amps you already have but will be of better quality than those you have in your garage or house. For some, the nostalgia trip is worth every penny.

However, buying used items is a risky business. Modern receivers will be more capable of handling a subwoofer’s requirements, but that doesn’t mean an old amplifier can produce the exact sound you are looking for.

However, there is one caveat. The equalizers on modern amps are not available for vintage receivers. This means that if you increase the volume, the bass will reach levels it shouldn’t. This can make the receiver sound unpleasant. There are certain volumes you shouldn’t exceed when connecting a sub.

How To Connect A Subwoofer To An Old Amplifier

Connecting An Active Subwoofer To An Old Amplifier

Connecting an active subwoofer to an old amplifier

Older amplifiers will have different outputs from modern ones. Many amplifiers will only have one output. You can find the matching port on the subwoofer and use that as the signal source for the amp. This is a classic feature that works well with subwoofers.

Some amplifiers from the past don’t have these ports so you may need to be creative. To make this possible, your amplifier will need a few things.

To play sets A and C simultaneously, it will need two speaker outputs. An active subwoofer requires a high-level input option.

You’re great to go if your amp and sub both have these features. To connect to regular speakers, set A on your amp. Your subwoofer’s high-level input should be connected to the B line. You should be able to hear the extra bass kick in when you play them both simultaneously.

Most amplifiers have markings that indicate where to plug in your subwoofer. The “subwoofer output” line on the B line will often be displayed.

It is easy to turn it off. Just turn off the B channel of your amplifier.

Connecting An Old Amplifier or Receiver To A Subwoofer With RCA Input Jacks

A line-level converter is a great way to connect a subwoofer that has 1 or 2 RCA input jacks but no speaker-level inputs.

What is a line-level converter? How do they work?

Line-level converters, also known as RCA speaker-level adapters, are small electronic devices that connect with speaker outputs from amps or receivers and scale down higher-voltage signals to a lower level (“line level”) These outputs can be connected to an amplifier, subwoofer, or receiver with RCA jacks.

Although they aren’t often used in home stereo systems, they can be very useful in-car stereos. They allow for the connection of a stereo to an amplifier or powered subwoofer without RCA outputs.

What is the cost of line-level converters?

The price of line-level converters varies depending on their quality and features. They are available in retail stores for $15-25 or online.

How to use a line-level converter

You will connect the provided speaker wire connections (marked with colors and striped) to convert speaker outputs from your receiver or amplifier to RCA jack outputs. This is just like regular speakers. Then connect RCA cables or a single cable depending on which one you have to your powered subwoofer.

The subwoofer’s internal electronics reduce the speaker output voltage of a receiver’s speaker and help to prevent noise from the audio path. The majority of speaker-level adapters don’t require a power source, although some do.

You may need a “Y” RCA adapter if your subwoofer only has a single RCA input jack. This will combine the receiver channels on each side of the output into a single mono RCA plug.

Subwoofers that have 2 (stereo RCA connectors) inputs will require a stereo male-male RCA cable.

How to Hook a Passive Subwoofer to an Old Amplifier

How to Hook a Passive Subwoofer to an Old Amplifier

It is much easier to connect passive subwoofers to older amplifiers. Passive subwoofers come with pass-through connectors, which allow you to connect them before the speakers.

The passive subwoofer can be connected to the amp by being treated as a loudspeaker and hooking directly into the speaker connectors.

Connecting your Stereo Receiver System to Your Subwoofer

Connecting your Stereo Receiver System to Your Subwoofer

If you do it correctly, your whole sound system can be improved. Subwoofers are also a benefit to stereo systems. Subwoofers can provide a deeper, richer sound and a more refined sound. The stereo system connects to the subwoofer in a slightly different way.

The subwoofer connection does not have bass management features. This is because the receiver is connected to the stereo system. This connection is made possible by the subwoofer high-level inputs Connect speaker cables to the stereo and sub via the subwoofer output jack. This is similar to a vintage amp with no preamp output. The double connection allows your stereo and subwoofer to receive the full sound frequency effect, including the bass, treble, and midrange.

The subwoofer’s low pass filter will tell you how high the sub can reflect. The upper frequency of speaker drivers up to 5 inches in height will be 80Hz, but speakers 4 inches or less will have a frequency between 100Hz and 100Hz.

Connect A Subwoofer To A Vintage Receiver Without an Out

You can still connect your vintage amp to your subwoofer even if you don’t have one. To add some support, if your receivers have an output, you can connect a pair of interconnects to the Preout and then pass them into the subwoofer. On some amplifiers, the preamp output may be labeled ” PRE OUT”. The Y adapter is required for subwoofers that have only one RCA input. The adapter has one male RCA at the end and two female RCAs at the other end.

If your amplifier does not have a preamp output, you can still connect the subwoofer as if it were a normal speaker. You will need to run speaker wires from your amp’s speaker terminal to the subwoofer’s speaker-level terminal. This means that the front speaker will be connected to the speaker-level terminals of your sub.

Comparison of Stereo Vs Surround Sound Receiver Output Subwoofers

As an aside, a subwoofer connected to an older amplifier or receiver will not allow you to receive the dedicated bass sound channel (.1) as you can with surround sound receivers.

These are capable of extracting the bass sound from DVDs or other media and routing it to the LFE subwoofer output port. It might not be a problem.

Surround sound receivers or amplifiers can be used to play almost all of the sound through your main speakers, if necessary.

Some movies and music, such as music and movies, use the bass channel to draw you in. You won’t be able to achieve the same effect if you use a receiver that doesn’t output that signal. However, this is only true for surround sound mode.

It’s good to know that stereo mode works with both old and new receivers &s. They have similar subwoofer behavior, as can be seen here. You won’t notice it even if your amp or receiver is older.

This is a nice reminder to keep in mind if you are considering upgrading.


There are various ways to connect a subwoofer to an old amplifier. You can choose any ways that work with your device. Don’t hesitate to leave your comments below if you have any questions. Thank you for reading.

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