|PSB Stratus SubSonic 7 Subwoofer|
|Home Theater Loudspeakers Subwoofers|
|Written by Bryan Southard|
|Thursday, 01 November 2001|
The goal of a home theater system is much greater than to merely reproduce what is recorded on your DVDs. Its job is to transport you to the event being depicted in the film, an achievement known as suspension of disbelief. Movie producers go to great measures to create a hyper-realistic sense of impact, both visually and sonically.
In movies with even the slightest amount of action, you will find that no other component in your theater sound system compares to the subwoofer for impact, verisimilitude and ability to involve you in the movie. It is an essential ingredient to every home theater system. A subwoofer’s mission is to supply the lowest frequency information with ample sound pressure, which can fill your room with realistic and powerful low-frequency energy. It can often make your home theater experience more involving than that of your local theatrical release cinema complex. No home theater is complete without a subwoofer, regardless of how much low-frequency information your main loudspeakers are capable of supplying.
The SubSonic 7 is the flagship subwoofer of the PSB line. It measures 17.5 inches wide, 19 inches tall and 17.5 inches deep including 1 inch for feet, a basic cube weighing just a little under 60 pounds. The SubSonic 7 has a single 15-inch driver with a rated frequency range of 22Hz to 150Hz, with a low frequency cutoff of 18Hz at –10dB. The SubSonic 7 is driven by an internal MOSFET power amplifier, which is capable of 330 watts continuous and as much as 1200 watts dynamic peak power, able to deliver as much as 112 dB of sound pressure.
For connections, the SubSonic 7 has line level inputs and outputs, as well as high-level speaker wire connections. For controls, the SubSonic 7 has 180-degree phase inversion, which is useful for blending the sub in your room, master volume control, and a variable frequency crossover. The SubSonic 7 retails for a modest $949 and comes exclusively in a black roughcast finish.
There are several elements that should be considered when selecting the proper subwoofer for your home theater system. Size is important. In many cases, the subwoofer can be hidden or at least placed in a relatively unobtrusive location in your home. Subwoofers come in a variety of sizes, ranging from mini-cubes to quite expansive packages. Designs that focus on small volumes often develop great pressure based on long throw and small diameter drivers. These subwoofers supply a great amount of bass pressure for their size, but can lack accuracy due to distortion caused by the driver’s inability to react quickly enough due to its long travel. This does not mean that all subwoofers with larger enclosures and drivers are better than mini-cubes, but larger drivers may have advantages.
Today, most subwoofers come with internal amplification and crossovers – a configuration often called "Active." There are many advantages to an active subwoofer. Most home theater receivers, as well as separate surround sound processors (SSP), come with LFE modes that allow you to select whether to send full-range information to your main loudspeakers, or to redirect the lower-frequency information to your subwoofer, limiting the low-frequency information to your mains and alleviating the demand on your system’s amplifiers. This can often improve your system’s overall sound, depending on the ability of your amplifiers to drive your main loudspeakers at full range.
The phase inversion switch is a necessary ingredient for successfully blending the sub with your main loudspeakers and the rest of your home theater system. In simple terms, phase refers to the timing associated with the push and pull of a speaker driver. If information from your main loudspeakers "push" reaches you at the same time as that of the subwoofers "pull," it will sound compressed and lack tightness. This seems simple, but if the distance of the two to your listening position is different, obstructed or subject to reflections, they may reach you in an inverted phase. The phase inversion switch can correct some of these sonic anomalies to add greater focus and impact.
There is perhaps no greater test for subwoofers than the original "Jurassic Park" (Universal). I personally prefer the DTS version of this epic thriller. In the scene where the T-Rex has escaped and is terrorizing the stranded children, there are periods of extreme low-frequency information that lend themselves nicely to subwoofer evaluation. I like to focus particularly on the scene where T-Rex is beside the car, emitting a vibrant low-frequency rumble that emanates from deep within the animal’s large body. This rumble can either sound rich and taut, or loose and resonant. The PSB SubSonic 7 controlled this information very well, supplying extremely solid low-frequency support. It has overall quickness that allows this sub to rock and roll, yet disappear nicely. A sub that blends well and supplies accurate information will disappear. A sub, regardless of its performance, that draws attention to itself is either not set up correctly, or is not supplying information as the filmmakers intended.
On the Disney adventure "Dinosaur" (Disney DVD), when compared to the Sunfire True Subwoofer Architectural, a previously reviewed product priced at $1,195, I found the sub delivered greater accuracy, primarily in scenes where the low-frequency information was sustained. Sustained bass can be very troublesome, due to a driver’s inability to work accurately when its motion is interrupted during travel by additional information. The SubSonic 7 tended to sound generally less compressed and provided more dynamic impact. In scenes like the final conflict, the sub blended impressively well with my Revel Salon’s ($18,000 per pair) and provided the much-needed air movement to make this scene energetic and exciting. I chose to run my mains full range and ran the SubSonic 7 at a crossover setting of 65Hz. Would I match Revel Salon’s with a $1,000 PSB subwoofer? Most likely not, considering how good the Revel B15 ($3,000) is. However, the PSB could unexpectedly keep up during my famous peel-the-paint-from-the-ceiling movie sessions.
At present, you can purchase any number of subs that are considerably smaller in size than the PSB SubSonic 7. Although the SubSonic 7 is the largest in the PSB line, it is also a good match for some higher-quality home theater systems. In many applications, the SubSonic 7 may be considered too large, both physically and visually. Some rooms may lack the appropriate space and/or some owners may find the piece visually obtrusive. In addition, the SubSonic 7 only comes in the roughcast black finish. In beautifully decorated living environments, if you cannot hide the subwoofer, you would at least like to dress it appropriately. The PSB SubSonic 7 does not provide an option for wood grain finishes however, a high-gloss black top is available. It must be understood that PSB has positioned this product without frills at a price point that provides considerable performance at a reasonable dollar amount.
What I enjoy most about home theater is the excitement and experience of being transported to another place, the opportunity to run from dinosaurs and the thrill of hanging out with a Space Ranger and other toys. Home theater can take you to the movies in the convenience of your home, void of the inconsiderate coughing and sneezing from behind, and irritating conversation during the film. More important, contemporary home theater systems can deliver better and bigger sound at a less than monstrous price. Many home theater systems can sound world-class at a price that most can afford. As you select your system, pay appropriate attention to your subwoofer choice. It will provide much of the thrill in your movies. There are many products available and the decision isn’t an easy one. Unlike loudspeakers, you can’t easily evaluate subwoofers. It is not as easy as playing some music through them and picking your favorite. Take the opportunity to discuss this choice with your local retailer. I found the PSB SubSonic 7 to be a great choice for home theater systems with a large variety of price ranges. It will provide you with solid, accurate energy for both music and movies. The Sub 7 has power, accuracy and finesse at an affordable price and the ability to make your movies rock. It’s a box that you can set up and forget, then begin enjoying your movies as you never have before.