December 2002Revel Performa B15 Subwoofer
by Doug Schneider
Subwoofers are common in music systems today, but this certainly hasn't always been the case. I remember when I went shopping for my first stereo system in 1981. PSB, a small company at the time, recommended satellite speakers with a subwoofer as an alternative to larger floorstanding speakers. This wasnt a revolutionary idea -- it made a whole lot of sense -- but it definitely defined a niche in the speaker market, no matter how good an idea a sub/sat system was.
Audiophiles of the time, though, wouldnt have it. Although they certainly liked the idea of splitting their electronics into as many component chassis as they could, they wanted their stereo speakers only -- and preferably large stereo speakers.
But in a way, the resistant audiophiles had a point. Although the sub/sat concept allows you to optimize the satellite speakers for best imaging and tonal balance and the subwoofer for best bass response, blending the subwoofer with the satellites has almost always been difficult. Even today, in most systems, you can hear the sub -- almost as if it were a part of a different system altogether. So although the idea has always held a lot of promise, you had to fight to realize the potential.
Enter the $2995 USD Revel Performa B15, the most versatile subwoofer Ive come across. The B15 finally fulfills whats been promised to hardcore audiophiles for so long: perfect integration along with staggeringly deep bass.
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. Thats 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, youre out of luck. The B15 wont 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. Thats true of the equalizer section, which is only across the top. Below that section are the input and output sections that dont 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. Whats 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. Whats 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 subs 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 Ive come across. But theres more. Were 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. Its doubtful that youll simply tune the B15 by ear with a few turns of the dials. But dont 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. Its about a 1-meg download from Revels website, and once its on your hard drive, it takes about three seconds to install. Its 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).
While setting up the B15 may seem like a lot more work than you want to invest simply get some low-end grunt from your system, believe me, the time spent is worth it. After all, if you get a sub as advanced as the B15, you will want to match it to your speakers perfectly -- or you might as well be back in 1981.
System and setup
I used the B15 during the review period with a variety of bookshelf speakers, including the Polk LSi9, Axiom M2i, Energy Connoisseur C-3, and, of course, Revels own Performa M20. Amplifiers were all of the integrated variety with pre-outs and amplifier inputs -- the Perreaux 200iP and the Arcam FMJ A32. The CD player was the Arcam FMJ CD23T, and cabling was all by Nirvana Audio.
Its no use telling you much about the way I set the B15 up with each speaker because doing so will tell you almost nothing that you can use. Every room and every setup in that room will be different. In fact, setup would vary in my own room with the same speakers if I simply changed the position of the B15 only a little bit. Getting the perfect sub/sat blend is a combination of positioning the speakers just right and then using all those inputs, switches, and dials that I discussed. Leave everything the same in your system and move the B15 to another point in the room and youll be fine-tuning it again. In other words, no matter what I say, youll be plugging and playing in your own room, and thats exactly why all the controls and the special software are available.
A good number of consumers (and even some reviewers) like to evaluate subwoofers with the biggest explosions they can find -- and thats it. Usually demo material is something like the depth charges on U-571 or deafening low-bass attack from the latest Hollywood epic. Certainly these can tell you something about a subwoofer, such as how loud it will play and if the woofer will crack or make some other obscene sound at high SPLs. But after I found out that the B15 can certainly play louder than I or my room could tolerate, my goal was to see how well it would work in my music system and if it would it be able to play with the same fidelity as my main speakers.
It's disappointing to see subwoofers with huge drivers and impressive low-end response that, when they start playing music, turn to plodding mush. The B15 isnt that kind of sub -- it makes bass frequencies sound fast. No, it doesnt turn 40Hz into 80Hz, but what it does is hit down low in a very tight and tuneful way. Its almost nimble in the way it handles bass -- a heavyweight with the finesse of a lightweight. If you have fast, tight, and articulate speakers, this subwoofer will likely blend beautifully, continuing the same high-quality sound far below what those speakers can do alone. And if you thought you were already hearing most of what is down low, you might be in for a surprise when the B15 kicks in.
Im often surprised at just how much presence can be added to music by reinforcing the low end. Ive been listening to Bruce Springsteens The Ghost of Tom Joad [Columbia 67484] lately and really enjoying the way some of my speakers convey Springsteen's richly textured, closely miked voice. I thought it was already very full and robust-sounding -- then I powered on the B15. Springsteens voice didnt get any deeper, of course, but there was more musical information below what the smaller speakers could deliver, and the B15 greatly increased the weight of the performance. As a result, Springsteens voice stood out even more starkly in the mix, and the sense of space grew to the point of being enveloping.
And this leads me to another point: a subwoofer doesn't just increase bass response so that drums, piano, and other instruments can be reproduced more faithfully. Delivering more down low often increases the space conveyed by the recording as well, and thats precisely what I was hearing with the Springsteen disc. All things being equal -- main speakers not moved, listening position the same -- the location of the images stays the same, but the illusion of the soundstage's scope increases substantially. Another good example of this can be heard on the opening track of the Cowboy Junkies The Trinity Session [RCA 58568]. Without full-range bass, the size of the space in which the recording was made is only hinted at; with full-range bass such as the B15 provides, the rooms volume explodes before you, and you feel like youve been launched into the venue.
Of course, having that extra heft down low also helps reproduce the instruments that play in the bass region more faithfully. The way the B15 does it is with some of the greatest control Ive heard from any sub. Telarcs first recording of Carmina Burana [Telarc CD-80056] was delivered with weight and impact that I had never experienced from any floorstanding loudspeaker Ive had in my system. The big bass drums were deep and tight, making the impact hard-hitting and visceral. "Tight as a drum" is a well-known (and perhaps worn-out) phrase, but it applies perfectly to the B15. Although someone may have a room thats big enough to accommodate more bass output than the B15 provides, I would say that there arent many of these people. One B15 on its own has prodigious output capabilities with gut-wrenching impact.
Revels little Performa M20s rival speakers costing much more than their $2000 price, albeit at the expense of visceral bass. Add the B15 subwoofer and you have a $5000 combination that holds its own against any speaker in that price range and against many speaker systems costing quite a bit more. Norah Jones piano-dominated Come Away with Me [Blue Note Records 32088] proved to be a helpful setup and evaluation disc because piano is one of the toughest instruments to reproduce correctly for standalone speakers or sub/sat combinations. Done poorly, the low end of the piano can sound wooly and indistinct, and with a poorly set up sub/sat speaker combination, the discontinuity between the main speakers and subwoofer can be heard more readily. When I had the B15 set up right, I knew it. The rendering of Jones' piano, particularly the low end, was done with extraordinary resolution and clarity that were simply better than the sound of any single-piece loudspeaker that has entered my listening room. Such performance may take you a while to discover, but once you do, youll be rewarded.
One subwoofer that I lived with for quite some time is Paradigms excellent Reference Servo-15. This subwoofer retails for $1500, half the price of the B15, and its every bit as impressive for its price as the B15 is for its price. To me the Servo-15 is an excellent choice if you can't afford the B15. But, if you have the cash to spend, the B15 will give you more. But more what?
Based on company-supplied specifications alone, the B15 can put out greater SPLs. However, dont consider this a decision-breaking specification. Both subs play extraordinarily loud, and if youre taxing them theres a good chance that youve not only deafened yourself but your neighbors as well. I never came close to wearing either out.
In terms of build quality, they are comparable with their real-wood veneers. Styling is a bit different, though. The Servo-15 is actually a smidgen larger, but I found that its sloped top edges make it a little sleeker-looking. Nevertheless, I find that big subwoofer boxes can only be so attractive, and neither is going to make an impression on design-conscious consumers. How often are subwoofers centerpiece components to show off anyway? Theyre almost always unsightly, and that's why people buy subwoofers and usually shove them off to the side or into a corner.
Where the B15 takes a significant lead is in its rich feature set. The Servo-15 is more conventional in that regard and cant match the low- and high-pass options, not to mention the parametric equalizer that comes built into the B15. No doubt, this is part of what you pay for with the Revel. As well, the B15 sounds a little tighter and more articulate than the Servo-15. The Servo-15 is a great choice for inclusion in an excellent audio and home-theater system to make it truly full range. I used it to great effect with my Reference Active/40 speakers. But I found the B15 just a little more precise.
So in my books, you get what you pay for. The B15 is about double the price and offers significantly more features along with a step up in performance.
At $2995, the Revel Performa B15 subwoofer is not cheap, but its value is apparent. The B15 has more relevant features than any other all-in-a-box subwoofer for home audio that Ive seen. And it isnt just a subwoofer to mate with Revel speakers -- its versatile enough to match with just about anything. And that anything pertains to the most precise and exacting speakers you can find. This "tight as a drum" sub has the sonic fidelity to complement the finest audio systems.
The Revel Performa B15 is a longstanding promise fulfilled. And while this subwoofer is not exactly new -- its been on the market for a couple of years -- it will more than likely be a benchmark of sorts for some time to come.
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