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Most subwoofers are rather simple and in need of only a paragraph or two to describe their features. Not the B15. There is a lot to this subwoofer.
At the heart of the B15 is a 15" "ultra-rigid Kevlar pulp and alloy composite" woofer driven by a 1000W amplifier (reportedly capable of 1400W peaks). Revel says the B15 can produce 30Hz at 126dB in a "standard listening room." The driver has a 3" voice coil and a magnet that weighs more than eight pounds. All of this adds up to a subwoofer that can move serious amounts of air, extending a sub/sat speaker system to the point of being considered full range.
Despite the heady specifications and macho image, the B15 is reasonably compact. The cabinet is made from 1" MDF and measures 18 3/4"H x 17 3/4"W x 18 15/16"D. That’s pretty small for what the B15 does. Granted, though, the B15 is not all that light -- its shipping weight is 110 pounds. I sort of rolled it out of the box and pushed it around the floor to get it into place. The review sample came in real-wood black-ash veneer, which looks kind of stealthy. Rosewood, sycamore, and cherry finishes are also available at a $300 increase in price; other finish options exist too. A round grille is included to hide the big silver woofer.
The B15 works at the line level -- single-ended or balanced inputs are standard. For most people with a separate amp and preamp, a surround-sound processor, or an integrated amp with preamp outs, this will be fine. But if you have an integrated amplifier with no preamplifier output, you’re out of luck. The B15 won’t take speaker-level connections.
The back panel is a bit confusing because at first, second, and even third glances it looks like it has three discrete sections: EQ 1, EQ 2, and EQ 3. That’s true of the equalizer section, which is only across the top. Below that section are the input and output sections that don’t correspond to the EQ 1, EQ 2, and EQ 3 headings at the top. Once you realize this, everything suddenly makes more sense. But I would recommend that a line be drawn or some shading put in to help buyers clue-in more quickly.
The most important section is on the left side. Unless you are using some sort of filter external to the B15, you will connect the left and right interconnects from your preamplifier to the RCA or XLR inputs and engage the Low Pass Filter switch, which limits the B15 to playing frequencies below whatever the Low Pass Frequency setting is. The factory default for the Low Pass Filter is a high point of 80Hz, but depending on how deep your speakers go, this can be adjusted downward in 10Hz increments to a low point of 30Hz. What’s very cool here is that at the flick of a switch you can change the slope of the Low Pass Filter to be either 24dB or 48dB per octave -- just one of many options that will help you integrate the B15 perfectly with your speakers.
On the right side is the High Pass Output, which you may or may not use. This is a line-level output that goes out to your power amplifier and, in turn, powers your main speakers. Like the Low Pass Filter section, the High Pass Filter can be adjusted from 80Hz downward in 10Hz increments, and the crossover slopes can be switched between 12dB and 24dB per octave. There are reasons for and against using this section, and whether you use it will likely take some experimentation to see whether or not you come out ahead with it.
The argument for using it is that it will cut off the bass at a certain frequency (that you can set on the B15, just as with the Low Pass Filter section) and this will relieve your main speakers and power amplifier from having to produce bass that the B15 is already covering. Makes sense. The argument against using it will most likely come from purists. Using this filter sticks more electronics in the path of the full-range signal, not to mention two sets of interconnects and connectors. Makes sense too. What’s most important about all this is that you have two options -- simply try each.
In the middle of these two sections there is an Aux Output section for daisy-chaining multiple B15s for supreme bass-output capability and lower distortion. Above this area are the sub’s Low Pass Phase (0 to 180 degrees) and Low Pass Level controls. Fine-tune these to get the best sound and ideal output level.
With these features alone, the B15 has more functionality than any other sub I’ve come across. But there’s more. We’re now back to those EQ 1, EQ 2, and EQ3 sections that I first encountered. This is a built-in parametric equalizer that allows you to tailor the frequency response at three points between 18Hz and 80Hz. Does the placement of the speakers and sub in your room boost certain frequencies? Or is there some suckout that you need to get rid of? Simply select the frequency you wish to affect and then adjust the bandwidth of the change from 0.1 to 1 full octave. Finally, adjust the level -- increased up to 6dB or reduced by up to 14.5dB.
If this all sounds a little daunting, it is. It’s doubtful that you’ll simply tune the B15 by ear with a few turns of the dials. But don’t worry -- basic setup is as easy as with any subwoofer, and for the advanced stuff Revel supplies a CD of test tones. Plus, there is a special B15 setup disc that helps guide you through the process. There is also Low Frequency Optimization (LFO) software that Revel has developed and which runs on Windows-based PCs. It’s about a 1-meg download from Revel’s website, and once it’s on your hard drive, it takes about three seconds to install. It’s user friendly, and it even lets you be honest in the privacy of your own home and declare yourself a Novice or an Expert. You use this software in conjunction with the CD of test tones and an SPL meter (the popular Radio Shack model will do). |
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發表於 2010-3-31 20:30
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