Updated: Sep 6
Complete Illustrated Guide to Subwoofers
Introduction Having the right subwoofer makes a real difference in the quality of your home theater experience or multi-room audio experience. You need a subwoofer in your system to faithfully reproduce the low frequencies of your music or movie soundtrack. The experts at Bravo AV will help you choose the right subwoofer for your application. We offer a selection from the finest brands and have solutions in all shapes, sizes and formats.
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What is a subwoofer? A subwoofer is a speaker that is specifically designed to reproduce low frequency sounds and is responsible for truly immersing yourself in a movie or concert. Most modern subwoofers include a specialized amplifier. This amplifier can be built into the enclosure of the subwoofer, or it can be a separate unit. The beautiful and powerful JL Fathom F112
What is bass? Bass notes are those that cover the lowest frequencies of the audio spectrum, typically, 20 to 160 Hz. We describe frequency in units called “Hertz,” which represent the number of cycles per second of the sound. The complete range of frequencies humans can hear is generally defined from 20 to 20,000 Hz. The lower frequency range, from 20 to 160 Hz is the “bass” range. The highest frequency range, from 2,500 to 20,000 Hz, is called the “treble” range. That leaves the middle section, between 160 and 2,500 Hz, which we call the “mid-range. There are a surprising number of instruments that generate low frequency: drums, standup bass, cello and harp, bass guitar, organ, the low end of a piano, bass and baritone singers, and, of course, the explosions experienced in a movie. Bass is often described as the sound that you feel as well as hear—the powerful vibrations that physically shake you in your seat. Conventional speakers, be they 2-way or 3-way, typically take care of higher- and mid-range frequencies as well as a certain amount of bass. Subwoofers are designed to take on the task of handling the deep, detailed and rich bass that most loudspeakers struggle with.
Do I need a subwoofer? You absolutely need a subwoofer in your Home Theater or Media room as the sound track has a Low Frequency Effects (LFE) output that sends information to the subwoofer. If you do not have a subwoofer your sound track will be very thin and lack emotional impact. We recommend two subwoofers in HT Speakers in key rooms in your home’s multi-room audio system will benefit greatly from a subwoofer. The subs can be in-ceiling or in-wall.
What size subwoofer do I need? Generally speaking, the larger the surface area of the woofer, the deeper it will play. Woofers come with drivers that range in size from 6 to 15 inches. While it may not seem like a big difference to go from a 10-inch driver to a 12-inch driver, doing so actually gives you a driver that is 44 percent bigger—a significant difference. JL Audio has four families of subwoofers. Listed below in increasing quality, they are:
Dominion: 8-inch or 10-inch drivers
E-Sub: 10-inch or 12-inch drivers
Fathom: 12-inch or 13.5-inch drivers
Gotham: 5-inch drivers
JL Audio also offers fantastic in-wall (IW) and in-ceiling (IC) subwoofer systems.
Fathom IWS-108 and ICS-108: 8-inch driver
Fathom IWS-208 and ICS-208: Dual 8-inch drivers, each in its own cabinet
Fathom IWS-113: 13.5-inch driver
Fathom IWS-213: Dual 13.5-inch drivers, each in its own cabinet
Home theater Two 12-inch subs are our minimum recommendation for home theaters. By using 2 to 4 subs we can get better distribution or bass energy in a theater. Multi-room applications One sub is usually enough. Bigger rooms require bigger subwoofers. How much power does my amplifier need? The spec to pay attention to is the sub's continuous power, or RMS rating. You will also see a "peak power" rating listed on many powered subs. Peak power is what the amp can deliver for short bursts. RMS is a better number to make comparisons with. Home theater 1000 watts RMS Multi-room applications 500 watts RMS Good bass vs. just a lot of bass [Quantity vs. Quality] Based on the above two paragraphs, if money were no object, you would think, “OK, I will get the biggest driver size and the most powerful magnet.” However, power without control is useless. It is critical that the amplifier maintain precise control of the driver and that the drive cone does not flex when in operation.
There are moments in movies that might require a lot of bass output (quantity), and it is important that the subwoofer system can handle these passages comfortably. Bass quality, on the other hand, is important at any listening level with any type of program material.
Many people equate subwoofers with the thump-thump they hear from other cars at stoplights. This is bad bass. Volume at the expense of quality. At Bravo AV we never sacrifice quality for volume. At Bravo AV we make sure that the bass energy dovetails with the rest of the musical spectrum so that it presents as a well-integrated whole. The goal with any speaker system is to accurately recreate all frequencies in the original recording. Well-reproduced bass it critical to letting music have its greatest emotional impact on the listener. The paradox of having a good subwoofer is that the difference it makes should be discreet, not glaringly obvious. The harmonious blending of all the speakers in a surround sound system is accomplished when Bravo AV acoustically tunes the room. Where can your sub go? Power: All subs need AC power. For an in-room unit the power needs to be by the sub location. For in-ceiling or in-wall subs you need power by the subwoofer’s separate amp, which is typically located with the other AV equipment. Subwoofers can be located:
In-room as a free-standing cube on the floor
We don’t recommend locating subs inside a piece of furniture as the power generated by the sub can shake items in the cabinet. Characteristics of a subwoofer
Type: In-room or freestanding, in-wall or in-ceiling. See, “Where can your sub go?”
Construction [Enclosure Type]: There are two main types of subwoofer enclosures: sealed and ported. With sealed enclosures (also known as acoustic suspension) air does not move in or out. Ported boxes (or bass reflex enclosures) have a built-in air vent that helps reinforce low bass output. Both design types can sound good. At Bravo AV we prefer JL Audio’s sealed design coupled with a powerful amplifier.
Power: As mentioned above we like at least 500 watts for a multi-room audio application and 1000 watts for a home theater application.
Cabinet construction: You want a very well-made sturdy cabinet that is well braced to avoid any cabinet resonance.
Dimensions and weight: For in-room sub placement you need to pay attention to its dimensions. A 10-inch sub will be approximately 16 inches tall, 16 inches wide, and 18 inches deep. A well-built sub is going to weigh a lot. For instance, the JL Fathom F112v2 weighs 115 pounds.
Drive (cone) size: Minimum 8 inches
DSP and other controls: Home theater and high-performance media rooms need subs that have DSP capability and can be tuned to the room in which they will be used. These features are generally included in premium subwoofer models like the JL Audio Fathom v2 lineup and the Gotham v2.
Frequency response: Typically, 20 to 200 Hz. Be very careful to look at the dB variance they are quoting. It should be no more than + or – 3dB.
Wireless option: Wireless kits are available. But at Bravo AV we prefer a wired solution.
An exploded diagram of what goes into a JL subwoofer
Absolute Sound Magazine – The Competitive Landscape An article recently published in Absolute Sound magazine, “A Short Guide to Subwoofer Features & Specifications,” looked at subwoofer offerings from 31 manufacturers. The publication gathers data on 141 subwoofers. Bravo AV looked at every offering in relation to the JL Fathom F1112 v2, which—while not the most powerful in the JL Audio line—at 1800 watts, is one of our favorites. There were 11 subwoofers that were more powerful, but none at the same price as the JL. In fact, the most expensive subwoofer was 35 times more costly!
About JL Audio and JL Awards JL Audio is an independent, privately held U.S. company active in the home, mobile, powersports and marine audio markets. JL Audio focuses on delivering unique engineering, superior quality, and high-performance audio to its customers around the world. Behind the company’s efforts is a strong belief that great audio has real value, and that customers can tell the difference. Founded by long-time friends Jim Birch and Lucio Proni in 1975, JL Audio has grown over the years into a global brand with headquarters in a 200,000 square foot facility in Miramar, Florida, and engineering facilities in Phoenix, Arizona, and Portland, Oregon. JL Audio home subwoofers have been awarded the highest honors from the audio press, including: Class A – Recommended Component from Stereophile Editors’ Choice from The Absolute Sound Golden Ear Award from The Absolute Sound Product of the Year from Home Theater and Sound
For additional resources, please visit our page on Home Audio with articles like this on everything you need to know about speakers and surround sound. Additionally, you can check out our photo gallery on the same page to explore our previous work.
Bravo AV is proud to be an HTA (Home Technology Association) Certified Installation Firm and professional A/V experts. Tom Curnin, the owner of Bravo AV, is a CEDIA Professional Designer, a certified THX Level 1 home theater professional and a member of the Home Acoustic Alliance trained to Level II. You can contact Tom directly at (908) 953-0555 or through email at Tom@BravoAV.com.