Setting Up Bass In A Home Theater Correctly With Bass Management

The Key To Great Home Theater Sound Is All About The Bass

Example of home theater speaker setup menu spotlighting bass management
Images provided by Anthem AV

The home theater experience just wouldn't be the same 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 that is all they have to do to get great home theater sound.

However, it takes more than that—If you have a home theater receiver, speakers, and subwoofer, you need to perform some additional steps to get the great sound that you paid for.

You need to make sure that 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) are sent to the correct speakers. This is referred to as Bass Management.

Surround Sound and Bass

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

For example, in surround formats dialog is assigned to the center channel, the 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. Also, there are some surround sound encoding formats that assign sounds to height or overhead channels.

However, with all surround sound audio encoding systems, the extreme low frequencies are often assigned to their own channel, which is commonly referred to as the .1, Subwoofer, or LFE channel.

Implementing Bass Management

In order to replicate a cinema-like experience, your 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, but you need to do some preliminary setup, such as placing your speakers in the proper locations, connecting them to your home theater receiver, and then designating where the sound frequencies need to go.

Set Your Speaker Configuration

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

After you have your speakers with (or without) a subwoofer connected, go into your home theater receiver's onscreen setup menu, and look for the speaker setup menu.

Within that menu, you should have an option that enables you to tell your receiver what speakers and subwoofer you may have connected.

Set Speaker/Subwoofer Signal Routing Option And Speaker Size

Once you have confirmed your speaker setup, you can begin the process of designating how to route sound frequencies between your speakers and subwoofer.

  • If you have floor-standing speakers as part of your home theater speaker setup, but do not have a subwoofer, in the speaker setup menu, designate that you don't have a subwoofer and the receiver will then 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) speaker/subwoofer setup. When this is done, 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 a lot of bass frequencies. However, chances are, they still can't reproduce the extreme low frequencies that a good subwoofer can.
  • By moving the 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 the 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.
  • The last and most common option is If you have small bookshelf-type speakers for the rest of your channels, in combination with a subwoofer, tell the receiver to route all of the low frequencies to the subwoofer only. This takes the low-frequency load off the smaller speakers since they do not have the ability to reproduce lower bass frequencies. In this case, if prompted, set all your speakers to "small".

Subwoofer vs LFE

When deciding which of the above options to use, another factor to take into consideration is 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).

The LFE channel contains specific extreme low-frequency information that can only be accessed by via the receiver's subwoofer preamp output. If you tell your receiver you do not have a subwoofer—you will not be able to access 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.

The Automated Path To Bass Management

After designating your 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. Some of these systems are Anthem Room Correction (Anthem AV), Audyssey (Denon/Marantz), AccuEQ (Onkyo), MCACC (Pioneer), DCAC (Sony), and YPAO (Yamaha).

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 onscreen 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 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 easy and convenient for most setups, this method is not always the most accurate for all factors, 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. This type of system definitely saves a lot of time, and for a basic setup is usually sufficient.

The Manual Path To Bass Management

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 what is referred to as crossover points.

What A Crossover Is And How To Set It

Having designated where the high/mid-range sound vs the low-frequency sounds need to go using the initial configuration setup discuss previously, you can proceed to manually pin down more precisely the best point where the frequencies that your speakers handle well vs the low frequencies that the subwoofer is designed to handle better.

This is referred to as the crossover frequency. Although it sounds "techie" the crossover frequency is merely the 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.

Although specific speaker frequency ranges vary between specific brand/model (thus the need to make adjustments accordingly), here are some general guidelines using speakers and a subwoofer.

  • 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 clue to finding a good crossover point is to take note of 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.

Another 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 will 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 will 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.