Are Two Subwoofers Really Better Than One?
Bring High-Fidelity Audio to Your Marietta Home with JL Audio Subwoofers
At GHT Group, we have become known for recommending two or more subwoofers for our JL Audio home theater and high-fidelity audio systems. The goal is to achieve the best possible integration of the subwoofer system with the listening spaces of your Marietta home.
Bear in mind that bass is the only part of the audio spectrum that we feel as well as hear. It is vital to the storytelling aspects of a film, whether in the form of explosive special effects or more subtle tones that create drama or atmosphere. In music, bass is quite literally the foundation. Getting bass reproduction right can immensely enrich your enjoyment of movies and your favorite music.
Let’s consider a few basic misconceptions that often get in the way of achieving great bass response in home audio and home theater systems.
MISCONCEPTION #1: There is only one “.1” subwoofer channel in multi-channel audio, so you only need one subwoofer to connect to it.
The truth is that the ".1" refers to a dedicated Low Frequency Effects (LFE) channel that is present in many (but not all) surround mixes. Some recording engineers never use it, others use it only for limited explosive effects, but it is not the whole of the bass in the overall audio mix. Main channels and surround channels also carry low-frequency information that combines with bass in the LFE channel. When a Receiver or Pre-Pro's bass management is set up for "no subwoofer," the surround recording's LFE channel audio is played back through any available speakers in the system. In systems that include a subwoofer or two, the LFE channel audio is delivered to the subwoofers by itself, or in combination with the low frequencies present in all the other audio channels. The latter happens when you select the "Small" setting for the main speakers and surrounds. Setting main and surround speakers to "small" and letting the subwoofers handle the low frequencies is usually an excellent practice.
MISCONCEPTION #2: Bass is non-directional, so you only need one subwoofer, and you can put it anywhere.
Here we have a valid observation (that bass below 80 Hz is very difficult to localize), leading to an unfortunate conclusion because a very important factor is being ignored: the listening room. Bass can be non-directional in an extremely large space like a basketball arena, but in the relatively small confines of a living space, the room boundaries contain and reflect low-frequency sound waves like waves bouncing around in a pool. This reflected low-frequency energy creates spots in the room where some frequencies are louder than they should be, and others are canceled out and sound very weak. The dips in response due to room acoustics cannot be fixed with equalization or with passive room treatments. No matter how much energy you put in a cancelation, the result is still a cancelation. Since we can't move the walls of the room, the placement of a single subwoofer becomes critical, and so does the location of the listener. In most cases, this relationship can be well-optimized for a single listening position, via careful subwoofer placement and the use of equalization technology. JL Audio’s DARO (Digital Automatic Room Optimization) analyzes the frequency response of the bass at the listening position and applies multiple EQ filters to cut any frequency ranges that have excessive energy at the listening position, thereby smoothing the bass response and making everything sound much better.
If all we wanted was lots of bass output with little regard for bass quality, we would simply stack a few subwoofers in the corner of the room and get tons of boom. This is not the approach we are suggesting when we recommend multiple subwoofers. The approach we recommend addresses the room acoustics issues we discussed above by distributing the sources of low-frequency energy within the room.
With the bass coming from two sources in two different locations, the response errors caused by reflected energy interact with the room and the listening position differently for each subwoofer. This has the effect of averaging the overall frequency response, allowing for much smoother frequency response in the best seat in the house, and also in the seats around it.
Add the power of DARO to this already smoother starting point, and you can achieve true, reference-quality bass in most listening spaces, over a wide listening area. The leap from one subwoofer to two subwoofers makes a profound difference!
Multiple subwoofers also help in reducing low-frequency distortion and offer improved dynamics over a single subwoofer. This is a simple function of having more radiating area, plus more power on tap. Each subwoofer works less hard for a given output level, staying comfortably in its linear operating range.
You will realize noticeable, measurable improvements as you add a third or fourth subwoofer, with diminishing returns after four have been well-placed and calibrated in the room. But, the step of upgrading from one to two subwoofers will deliver the most significant performance increase.
Want to learn more about how to use multiple JL Audio subwoofers to achieve high-fidelity audio in your Marietta or Metro Atlanta home?
Reach out to one of our experts by chatting live with us below, calling us at (770) 955-8909 or by filling out our online form.