Connecting and fine-tuning a subwoofer is far more complex than any other component in an audio system. The acoustic of your home theater room tends to have a significant effect on the performance of the subwoofer than any other loudspeaker. What’s more, most home theater systems do not come with dedicated subwoofer connections, and this makes it even more complicated to add this important component to your setup.
While adding a subwoofer to your audio system, you may have come across several acronyms, including LFE input, sub out, RCA, etc. Basically, these terms are used to refer to different connection types used to add a subwoofer to an AV receiver or amplifier.
The type of connection you choose depends on the ports available and the specific requirements of your home theater setup. So, what is LFE on a subwoofer, and is it as complicated as it sounds? In this article, we’ll explore everything you need to know about this much-talked-about subwoofer input to make it easy to integrate a subwoofer into your home theater setup.
What is an LFE input?
The LFE, an abbreviation of Low-Frequency Effects, is an input that is specifically designed to transmit low-frequency audio signals from the receiver to the subwoofer. From the definition, this input is used with a subwoofer, which is the speaker designed to handle the lowest frequencies in an audio signal. Such signals include bass notes in music and sound effects in movies.
In simple terms, the LFE is typically used to connect a subwoofer to a home theater or any other sound system. This input has a frequency range of 20 Hz to 120 Hz, which is the range of frequencies that are used for low-frequency effects in audio and video production. Some LFE inputs may also be labeled as subwoofer or sub inputs.
The LFE combines both the right and left channels, which allows you to use a single cable to send the signals to your subwoofer. So instead of transmitting the L and R inputs separately, the two are combined together and sent through a single LFE cable. As such, it may also be referred to as a ‘mono’ input, since it handles only a single channel of audio.
In most applications, this setup is often used to transmit intense low-frequency signals, thereby resulting in the reproduction of vigorous soundtrack effects in movies and films. This makes it the most preferred connection method since it allows you to transmit sufficient bass information between the subwoofer and the receiver.
When using the LFE input, the low-frequency audio signals are sent directly to the subwoofer, rather than being sent through the main speakers or satellite speakers in the system. This allows the subwoofer to reproduce the lowest frequencies in an audio signal more effectively, resulting in a more immersive and realistic listening experience.
However, not all subwoofers include the LFE input on them. Such subwoofers do not have the LFE channel, so you’ll need to devise other methods of connecting your subwoofer. The good thing is that such subwoofers will have additional audio inputs, such as speaker-level inputs or RCA, which you use to connect the subwoofer to your sound system.
Using an RCA cable to connect a subwoofer is not highly preferred, but it still achieves the same results. This connection splits the low-frequency signal into left and right channels before it is transmitted to the subwoofer where it is reproduced.
So, instead of combining the two channels, as an LFE channel does, the RCA connection sends the inputs into the corresponding channels (i.e. left and right), which is then followed by connecting the subwoofer to the receiver.
What is LFE channel?
In a surround sound setup, the LFE channel is the channel that is specifically designed to carry all the bass information, including the sound of explosions or thunders in a movie. If your subwoofer has an inbuilt LFE channel, the sub will usually have a port labeled LFE on its back panel. The channel is usually separate from the main audio channels, and it is typically used to enhance the overall audio experience by adding depth and richness to the bass output.
The LFE channel is often used in conjunction with the main audio channels to create a more immersive and lifelike audio experience. Contrary to the main channels, the LFE channel only handles the bass information, with the primary objective of easing the other channels off the burden of delivering the bass information.
The LFE channel is usually found in multi-channel setups where it is used to deliver separate bass sounds. For instance, a 5.1 surround sound setup will have 5 main channels that are often full range and a separate LFE channel, specially dedicated to the low-frequency sounds.
To get the most out of the LFE channel, you may want to fine-tune the level of other speakers to full range. The idea behind this is to enable the output of the speakers to be in line with the signals being carried by the LFE channel.
Another benefit of the LFE channel is that it allows you to connect your subwoofer to the home theater receiver using a single connection. This implies that you do have to deal with unsightly wires when setting up your home theater system. Furthermore, it is unlikely to get confused when connecting the cable since the LFE port is clearly labeled on the subwoofer.
What is a Sub out?
A sub out, or simply the subwoofer output, is an audio output found on home theater receivers, and is specifically designed to send low-frequency audio signals to an active subwoofer. The subwoofer then amplifies and reproduces these low-frequency signals, adding depth and richness to the overall audio experience.
The sub out port only allows the low-frequency or bass audio signals to pass through. This means that the high frequencies are filtered out, leaving you with low-frequency sounds only. The sub out uses a subwoofer cable to connect the subwoofer.
You can find this output on both home theater receivers and select stereo receivers as well. In some applications, the sub out is used to connect active speakers to enhance the overall home theater experience.
Sub out vs LFE
From a user point of view, an LFE input and a sub out may be used to refer to the same thing. The two ports are primarily similar in terms of the audio signal they are designed to handle, so it is pretty obvious to assume that the two are the same.
However, in the context of home theater systems, LFE input and sub out are two different things. LFE input is a term that refers to an audio input on a subwoofer that is specifically designed to receive the low-frequency effects (bass signals) from a home theater receiver. This input carries additional bass information from the receiver to the subwoofer where they are effectively reproduced.
On the other hand, the sub out refers to the audio output on AV receivers that is specifically designed to send low-frequency audio signals to a subwoofer. Most home theater receivers come with a sub out jack that is often used to connect the receiver to the subwoofer.
The primary difference between a sub out vs subwoofer LFE input is that the sub out is used to determine how all the bass content will be reproduced while the latter is specifically used to carry additional bass information.
In other words, the content carried by a sub out jack is very different from the one handled by an LFE input. While an LFE is primarily for supplementing the amount of bass information contained in an audio signal, a sub out is tasked with the responsibility of transmitting all the bass information at any given time.
Other Frequently Asked Questions
Do all subwoofers come with LFE input?
The primary role of the LFE input is to allow you to connect a subwoofer to your home theater receiver or amplifier. Most modern subwoofers are often equipped with an LFE input, but it is not uncommon to find one with the input.
If your subwoofer does not have LFE input, you can use an RCA connection to add a subwoofer to your setup. Some subwoofers may have the option of using both the LFE input and the RCA connection. In such a case, always opt to use the LFE input for the best audio experience.
Should I use the LFE input on the subwoofer?
If the LFE input is available on your subwoofer, it is recommended you take full advantage of it when setting up your surround sound system. The additional LFE channel helps to transmit and boost the total bass output, and this helps to enhance the overall sound quality. In addition, the extra LFE channel help relieve the other channels of the burden of transmitting bass sounds.
Are two subwoofers better than one?
Yes. A setup with dual subwoofers allows you to enjoy a more refined bass experience than when using a single subwoofer. This is because, two subwoofers reduce the likelihood of sound localization, thereby allowing you to hear bass as it is coming from all directions. However, to get the most out of your investment, you may want to take your time to learn how to properly set up dual subwoofers
A Parting Shot!
It is quite common to find people using an RCA cable or Y adapter to connect a subwoofer. In most cases, this connection works well, but it is often not the best method of setting up a subwoofer. Using the LFE channel provides an optimal way to connect a subwoofer to your AV receiver or amplifier without having to deal with an extra cable. The best thing about the LFE input is that the signal sent to the subwoofer is already filtered, and this eliminates the need for an external crossover.
