Low Level vs High-Level Input Subwoofer

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Updated October 26, 2022

The process of obtaining the best speakers for a home-theatre setup is often complicated. Whether you’re looking for a great midrange speaker or the best subwoofers, you need to understand every element to achieve optimal results. One area most overlook when dealing with subwoofers is the difference between low-level vs high-level inputs. However, although it’s an often neglected piece of the puzzle, it impacts the audio experience.

KEY TAKEAWAYS:

  • Depending on the stereo amplifier, you can connect the subwoofer to a high-level or low-level input audio signal.
  • High-level input is the standard speaker audio connection and comes with every subwoofer and stereo amplifier.
  • Low-level input is tailored explicitly as a subwoofer output to help play the lowest frequencies.

We have no shortage of subwoofer material for those wanting to learn more. For example, we have articles covering the difference between series vs parallel subwoofer wirings. And we also have explanations comparing square vs round subwoofers.

Differences Between a High-Level vs Low-Level Subwoofer Connection

You’ll notice various input options when looking at a subwoofer’s rear panel. There are multiple connection points, indicating high-level and low-level outputs.

Insider Tip

You can switch between an amplifier’s left and right channels if one side becomes damaged or unusable.

Most subwoofers come with both types of connections, but the type of power amplifier and content you wish to listen to determines which input you should use.

The main difference between low and high-level connections is that low-level connections produce more dynamic bass effects in surround sound systems.

The low-level connections are the red and white RCA connection points on the back of a speaker and amp. They are also often indicated by the term “Line Level,” a term synonymous with low level. When you see a dedicated low-level channel, the “LFE Channel” (Low-Frequency Effects) indicates that there is a unique subwoofer channel dedicated to surround-sound effects.

A common occurrence is for someone to have a subwoofer with both connection styles and an AV receiver with only high-level. In this case, you should use high-level input.

For more info on how various speaker connections affect performance, check out our resource comparing coaxial speakers vs component connections.

Warning

Always check that your speaker and power amp have the correct surround sound inputs so that they can play the appropriate bass response. Unfortunately, not all devices come with LFE low-level inputs.

Bass Sound Quality

Most of the time, the two inputs have no noticeable difference in sound quality. However, the difference in sound quality comes into play if there are specific audio formats, like surround sound theatre systems. Here the low-level audio signal enhances the bass sounds and effects.

Another facet that affects the subwoofer’s sound is its enclosure design. For more, we have an article comparing bass tubes vs subwoofer boxes.

STAT: RCA, low-level connections carry voltages that range between 2V and 5V. (source)

Versatility

High-level inputs are handy because they are guaranteed to connect to any external amplifier. Unfortunately, many older amps still don’t come with low-level dedicated sub-outputs.

Low Level vs High-Level Input Subwoofer FAQs

Do all subwoofers come with both high input and RCA connections?

Most modern subwoofers will have both types of connection. But many older units may only come with high-input connections.

Why does my subwoofer have 2 RCA inputs?

These two inputs split the connection between the left and right stereo channels.

What does the term "Active Subwoofer" mean?

When a subwoofer is called active, the unit has a built-in amplifier and doesn't need to be connected to an external power source.
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