Attaching a Subwoofer to a Home Theater
Having a subwoofer integrated within your home theater is essential for experiencing full and accurate sound. The Subwoofer is responsible for reproducing and projecting low-end frequencies well below the capabilities of most speakers. The subwoofer can range in sizes from as small as 6 1/2 inches or less to a massive 18 inches or more. They deliver that room-shaking bass that can be found in most movies and are also versatile enough to deliver warm, smooth bass found in most musical tracks. Subwoofers allow you to literally feel the audio, like a thump to your chest and a shake in your leg. This simple guide assumes that you already have an Audio/Video Receiver, including home theater speakers, and discusses how to determine the type of subwoofer you own, how to connect it, and where it should be placed within a room.
Step 1: Types of Subwoofers
A powered subwoofer (also known as an Active Subwoofer) does not require any kind of external amplifier because the amplifier is already built-in.
A passive subwoofer does not contain an internal amplifier and is usually designed to install into a wall. In order to function properly, it requires an external amplifier such as a power amp or one that is specifically made for subwoofers. Amplifiers designed for subwoofers will usually have the necessary adjustments to help tweak a subwoofer's signal for optimum low-end production. It is important to choose an amplifier that does not exceed the advertised wattage of the subwoofer. An amplifier that provides more wattage than what a subwoofer can handle may result in audio distortion, amplifier clipping, and overall damage.
Step 2: Connecting the Cables
Most modern Audio/Video Receivers (AVRs) have a dedicated subwoofer connection located on the rear input/output panel. Usually the subwoofer connection is labeled as "Subwoofer Out" or something similar. The subwoofer output connector often utilizes an RCA connection, a type of cable designed to pass audio and video signals. On some older AVRs, a direct wire connection where the subwoofer's speaker wire connects directly to the AVR's "subwoofer out" speaker terminal is utilized. Regardless of what type of connection is available, be it RCA or direct wired, it is highly recommended to use shielded, heavy gauge cabling specifically designed for subwoofers. Such cables provide a cleaner, more noise-free audio signal.
The image below shows two subwoofer outputs. Today's AVRs feature 7.2, 9.2, and even 11.2 capabilities. The ".2" means that there are two subwoofer outputs available so that two subwoofers can be used at the same time. If the AVR had only a 5.1 capability, then the ".1" would mean that it only has one subwoofer output and thus only one subwoofer can be used.
If your AVR does not have an RCA "subwoofer output" connector, then a different approach is needed. Some self-powered subwoofers are able to take the speaker-level signals from the amp and extract the low-end sounds. Connect speaker cable from the front-left and front-right terminal outputs located on the rear panel of your AVR. Now, connect the other end of the speaker wire to the speaker wire terminals on the subwoofer. The amplification circuitry will combine both channels to mono, extract the bass frequencies, and amplify the sound for the subwoofer speaker.
Step 3: Subwoofer Placement
- Subwoofers are omnidirectional, meaning that the subwoofer can project sound in all directions, unlike speakers that mostly project sound in the direction they are facing.
- Start by placing your subwoofer near the front of your home theater system. A few feet to the left or right of the screen is a good starting point. Keep in mind that you will need to run electricity, audio cables, or speaker wires to the subwoofer.
- Listen to some music or load up your favorite movie and give your home theater a listen while observing how the subwoofer integrates into the entirety of the system. Ideally, the subwoofer should be producing smooth, punchy, deep, and rounded low-end bass with a clear sound. If the subwoofer's placement is producing more of a boom rather than a punch, try adjusting its position.
- Most modern AVRs come with their own version of an auto calibration feature which can get your entire home theater system, including the subwoofer, sounding optimum regardless of the subwoofer's placement. The auto calibration features of modern AVRs help to take out most of the difficult and often tricky work of getting the best sound from your home theater. Reference your AVR's manual for more information on its auto calibration feature.
In addition to a subwoofer, there is also the Tactile Transducer. As mentioned in the above summary, bass is something that can be felt and these devices assure exactly that. The Tactile Transducer produces only the vibrations that come from low-end reproduction. Usually, these devices will attach to the underside of a chair or a sofa and will vibrate in-sync with the bass that is being reproduced from your home theater's subwoofer. The combination of a subwoofer and Tactile Transducer allows you to feel an explosion from a scene in a movie and feel the bass drum of a song more accurately. The Tactile Transducer takes audio listening and turns it into a sensory experience.