What Bass Management Is and How It Works

The key to great home theater sound is all about the bass

The home theater experience isn't complete without the thundering bass that shakes your room (and sometimes disturbs the neighbors!).

Unfortunately, after connecting all the components and speakers, most just turn everything on, raise the volume, and think they will automatically hear great home theater sound.

However, it takes more than that. If you have a home theater receiver, speakers, and subwoofer, additional steps are needed to get the best sound.

The high/mid-range (vocals, dialog, wind, rain, small arms fire, most musical instruments) and bass frequencies (electric and acoustic bass, explosions, earthquakes, cannons, engine noise) need to be sent to the correct speakers. This is referred to as Bass Management.

Example of Home Theater Speaker Setup Menu Spotlighting Bass Management
Images provided by Anthem AV

Surround Sound and Bass

Although music (especially rock, pop, and rap) may contain low-frequency information that a subwoofer can take advantage of, when movies (and some TV shows) are mixed for DVD and Blu-ray Disc, sounds are assigned to each channel.

In surround formats dialog is assigned to the center channel, main effect sounds and music are assigned primarily to the left and right front channels, and additional sound effects are assigned to the surround channels. Some surround sound formats assign sounds to height or overhead channels. The extreme low frequencies are often assigned to their own channel, referred to as the .1, Subwoofer, or LFE channel.

Implementing Bass Management

To replicate a cinema-like experience, a home theater system (usually anchored by a home theater receiver) needs to distribute sound frequencies to the correct channels and speakers—bass management provides this tool.

Bass management can be performed automatically or manually. Before starting, place speakers in the proper locations, connect them to your home theater receiver and then designate where the sound frequencies need to go.

Set Your Speaker Configuration

For a basic 5.1 channel configuration, connect left/right front speakers, center speaker, and left/right surround speakers. If you have a subwoofer, that should be connected to the receiver's subwoofer preamp output.

Home Theater Surround Sound Setup
Getty Images - adventtr

After your speakers with (or without), a subwoofer is connected, go into your home theater receiver's onscreen setup menu, and find the speaker setup or configuration menu. You should have an option that enables you to "tell" your receiver what speakers and subwoofer you may have connected.

Denon AVR-X2100W Speaker Configuration Menu

Set Speaker/Subwoofer Signal Routing and Speaker Size

Once you have confirmed your speaker setup, you can designate how to route sound frequencies between your speakers and subwoofer.

  • If you have floor-standing speakers, but don't have a subwoofer, designate that you don't have a subwoofer. The receiver will route low frequencies to the woofers in your floor-standing speakers. Also, if prompted, set your floor-standing speakers to "large".
  •  If you have both floor-standing speakers and a subwoofer, designate that you have a mixed (or both) a speaker/subwoofer setup. The receiver will route low frequencies to both the woofers in your floor-standing speakers and the subwoofer. Just as in the previous case, if prompted, set your floor-standing speakers to "large".
  • If you have both floor-standing speakers and a subwoofer, you can send all of the low frequencies to the subwoofer by designating your floor-standing speakers, if prompted, as "small". Even if your floor-standing speakers can pump out bass frequencies, chances are, they still can't reproduce the extremely low frequencies that a good subwoofer can.
  • By moving lower frequencies to the subwoofer-only, even if you have floor-standing speakers, you are not only extending low-frequency response further but since the subwoofer typically has its own built-in amplifier, you are taking a load off your receiver that it can use to more easily provide power for mid and high frequencies.
  • Experiment with both floor-standing speaker options (mixed or subwoofer only) for low frequencies and, hear what works best for you. You can always go back and redo your settings.
  • If you have bookshelf-type speakers for the rest of your channels, in combination with a subwoofer, route all low frequencies to the subwoofer only. This takes the low-frequency load off the smaller speakers since they don't have the ability to reproduce lower bass frequencies. If prompted, set all your speakers to "small".

Subwoofer vs LFE

When deciding which of the above options to use, note that most movie soundtracks on DVD, Blu-ray Disc, and some streaming sources, contain a specific LFE (Low-Frequency Effects) channel (Dolby and DTS surround formats).

Denon AVR-X2100W Subwoofer LFE Settings Menu

The LFE channel contains specific extreme low-frequency information that can only be passed through the receiver's subwoofer preamp output. If you tell your receiver you don't have a subwoofer—you won't have access to the specific low-frequency information encoded on that channel. However, other low-frequency information not encoded specifically to the LFE channel can be routed to other speakers.

Many home theater receivers provide outputs for two subwoofers.

Onkyo TX-NR787 Dual Subwoofer Output
Onkyo USA

Automated Bass Management

After designating speaker/subwoofer signal routing options, one way to finish the rest of the process is to take advantage of built-in automatic speaker setup programs that many home theater receivers provide.

Examples of automatic speaker setup systems include Anthem Room Correction (Anthem AV), Audyssey (Denon/Marantz), AccuEQ (Onkyo), MCACC (Pioneer), DCAC (Sony), and YPAO (Yamaha).

Denon AVR-X2100W Audyssey Start Menu

Although there are variations in the details of how each of these systems work, here is what they have in common.

  • A special microphone is provided that you place at your primary listening position that also plugs into your home theater receiver.
  • After you plug in the microphone, you hit a start button or select a start option from an on-screen menu. Sometimes the start menu comes on automatically when you plug in the microphone.
  • The receiver then emits self-generated test tones from each speaker that the microphone picks up and sends back to the receiver.
  • The receiver analyzes the information and determines speaker distance, balances the output levels between the speakers, and also finds the best points where the frequencies are divided between the speakers and the subwoofer.

Although convenient for most setups, this method is not always the most accurate, sometimes miscalculating speaker distance and the speaker/subwoofer frequency points, setting the center channel output too low, or the subwoofer output too high. However, these can be corrected manually after the fact, if desired.

Setting Bass Management Manually

If you are more adventurous and have the time, you also have the option of implementing bass management manually. In order to do this, in addition to setting your speaker configuration, signal routing, and size, you also need to set the crossover frequency.

What Crossover Frequency Is and How to Set It

The crossover is the frequency point in bass management where mid/high and low frequencies (stated in Hz) are divided between the speakers and subwoofer.

Frequencies above the crossover point are assigned to the speakers, and frequencies below that point are assigned to the subwoofer.

The crossover point for a subwoofer may also be referred to as LPF (Low Pass Filter).

Although specific speaker frequency ranges vary between specific brand/model (thus the need to make adjustments), here are some general crossover settings guidelines.

  • If you are using bookshelf/satellite speakers the crossover point between the speakers and the subwoofer usually lies between 80-to-120Hz.
  • If you are using floor-standing speakers at the crossover point between the speakers and the subwoofer can be set lower, such as around 60Hz.

One way to find a good crossover point is to check the speaker and subwoofer specifications to determine what the manufacturer designates as the bottom end response of your speakers and the top-end response of your subwoofer. Once again this is listed in Hz. You can then go into your home theater receiver's speaker settings and use those points as a guideline.

Denon AVR-X2100W Crossover Settings Menu

A useful tool in setting crossover points is a DVD or Blu-ray test disc that includes an audio test section, such as Digital Video Essentials.

The Bottom Line

There is more to getting that "knock your socks off" bass experience than just connecting your speakers and subwoofer, turning on your system and raising the volume.

By purchasing the best matching speaker and subwoofer options (try to stick with the same brand or model series) for your needs and budget, and taking some extra time to position your speakers and subwoofer in the best locations and implement bass management, you'll discover a more satisfying home theater listening experience.

In order for bass management to be effective, there must be a smooth, continuous transition, both in frequency and volume output as sounds move from the speakers to the subwoofer. If not, you'll sense an un-evenness in your listening experience—like something is missing.

Whether you use the automated or manual path to bass management is up to you. Don't get bogged down with the "techie" stuff to the point where you end up spending most of your time making adjustments, rather than enjoying your favorite music and movies.

The important thing is that your home theater setup sounds good to you.