Long ago, when audio systems consisted of 2 speakers, bass management was nothing a home user needed to be concerned about. The 2 speakers in the system were usually large tower or bookshelf sized speakers, and capable of producing bass frequencies on their own. With the widespread adoption of digital surround sound, combined with tiny speakers and powered subwoofers, properly configuring bass management is imperative for getting the most from your audio experience.

What is Bass Management?

Since many of today's speakers are no bigger than a coffee mug, they are often incapable of reproducing low frequency sounds. That, or there is a different speaker more suited to better produce bass effects than another.

Bass management is a process in the receiver that redirects bass frequencies from speakers that can't handle it to another speaker that can.

Audio engineers have no idea what your system consists of. Some people still use two large front channel speakers, others have two large fronts and small surrounds, and many use five small speakers and a subwoofer. Either way, an audio engineer mixes sound assuming that all speakers are capable of producing bass effects. This means that without bass management, all of your speakers would need to be large enough to produce the sound in your living room.

Most home users don't want five very large speakers in one room. Instead, many opt for smaller sized (known as satellite) speakers, with one larger box to produce bass (known as a subwoofer). It's these variations in size and capability that make bass management important.

If bass management is not properly configured, you may be relying on your tiny speakers to produce the majority of bass effects. This is like forcing a Honda Civic to pull a 2-ton trailer. The Civic may be able to budge it, but certainly not cross country. Forcing your tiny speakers to produce bass would result in sub-par bass performance (in some cases no bass at all) that could easily be corrected just by changing some settings in the receiver. If you don't feel the T-Rex's footsteps in Jurassic Park, you definitely need to read on.

Look to the Receiver For Guidance

If you think the world of audio hasn't changed much in the last 20 years, think again. The heart of the audio system is the receiver, which not long ago consisted of a pre-amplifier, two power amplifiers,

and volume control. Today, a receiver adds video switching, 5 or more amplifiers, and 1000 times more processing power than the first space shuttle.

Bass management happens in the receiver. Audio signals are processed in a digital domain, where the receiver can determine, in real-time, what audio frequencies make up the input signal, and what speaker they should be sent to. Those in the know would ask how signals can be processed in the digital domain when they are input via an analog connection. Simple. The receiver uses an analog to digital converter to convert the incoming analog signal into a digital one. This means that bass management can be applied to every audio source you own, including an 8-track player if you have one.

As brilliant as receivers are these days, they still have no idea what your speaker configuration looks like. So until they are given cameras as eyes, plus adaptive intelligence to automatically figure it out for you, they still rely on you, the mighty home user, to tell the receiver what your speaker configuration is like.

Small or Large? Simple, Right?

If you decided to step into your home theater receiver's menu when you first set it up, you probably found a section that gave you a choice to set your speakers as small or large. Perhaps you were confused why size matters to the receiver, but no matter. Soon you'll know what it's all about.

The size question your receiver poses instructs it on what to do with bass frequencies. Unfortunately, the simplistic design of this interface has some pitfalls that cause many users to set it improperly, and hinder their ability to get the best performance from the system.

First off, the receiver really doesn't care what the physical size of the speaker is. It only cares whether or not it is capable of producing bass. Thus, it makes an assumption; small sized speakers are not capable (or less capable) of producing bass, so I should route bass to somewhere else. It seems logical enough, but it's limiting in some cases. When set to small, the receiver cuts all of the bass frequencies from that speaker and sends it to another.

After all of the size questions, another question is asked. Do you have a subwoofer? In most cases, subwoofers are the most capable bass speaker in your setup, so you normally want all bass to wind up there. However, there are some cases when this is not true (see example system #2). Continued on page 2 >>