Revel B15 Subwoofer 
Home Theater Loudspeakers Subwoofers
Written by Jerry Del Colliano   
Friday, 01 June 2001

Introduction
The Revel B15 sub is the first subwoofer from Madrigal’s Revel speaker line in their comparatively affordable Performa series. Priced at $2,995 in Black Ash and $3,295 in faux Rosewood, Cherry or Sycamore wood veneers, the B15 addresses some traditional subwoofer problems with new, highly successful solutions. At nearly 20 cubed inches in size, the B15 is slightly larger than subwoofers like my reference Sunfire Signature, yet it still retains a modest physical footprint.

The B15 is far more than a product that simply fills out a product line. This is a major design accomplishment. First off, the output of this 15-inch subwoofer is staggering at 113 dB at 20 Hz and an awe-inspiring 126 dB at 30 Hz. Revel has made headlines with a Harman-financed research and development budget that makes other high-end speaker manufacturers sick with envy. The B15’s 15-inch driver is yet another example of how Revel is creating products that the rest can only hope to copy. This driver has an incredible three-inch maximum throw distance and very low distortion. Revel downplays the influence of JBL in their work, but set aside everything you have read in the tweak magazines and understand that JBL makes some of the finest subwoofers known to man for professional and studio applications. Having JBL technology and manufacturing techniques available to you when you are designing a reference level, high-end audio and home theater subwoofer has an effect that cannot be ignored.

The amplifier in the Revel B15 is an ass-kicker at 1000 watts, with peaks in excess of 1400 watts. This also helps to reduce the level of distortion and woofer recoiling problems. Upon studying many of the better subwoofers in the market, Revel found that nearly all of them change their roll-off points as the volume increases, which means that you get less lower bass as you crank the volume. Most subwoofers do this to overcome the use of weak amplifiers and/or the thermal release for their tremendous heat. The Revel B15 is physically larger than average and uses far better components to accomplish higher, more accurate output. The magnet on the B15 is 130 ounces and can move insane amounts of air because of a larger cabinet, an advanced driver and a monstrous amp.

Where Revel really steps on the accelerator is their addition of a three band parametric EQ. All great subs need EQ to attain the highest level of performance and integration with full-range loudspeakers, yet EQ has historically been much maligned by under-enlightened audio reviewers and stereo salesman for years. The B15 does give you EQ and, better still, the setup tools you need to make the EQ easy to use correctly.

Setup
The biggest breakthrough in the Revel B15 subwoofer is the LFO (Low Frequency Optimization) software, which is the first successful solution to the age-old question of how to correctly set up a subwoofer in a music and/or home theater playback system. In my system, the subwoofers have been set up by Bob Hodas, a world-renowned professional acoustician, using a SIM System II dedicated room analyzing system. While I recommend Bob Hodas with two big thumbs up for those who are looking to get the most out of their AV system, the Revel B15 with its LFO software is a huge step towards you being able to actually set up a serious subwoofer by yourself, with happening results in your system and, more importantly, in your room.

The Revel LFO software can be downloaded for PCs (or Macs using PC emulation software) from Madrigal.com and works in conjunction with a CD of 1/12 octave test tones provided by Revel in your B15’s packaging. You will also need a SPL (Sound Pressure Meter) from either Radio Shack (about $40) or a more accurate device, which will cost more.

As you start the LFO software, you can choose either the Novice or Advanced mode. Both modes lead to the same results. The Novice is more geared toward assisting you, the end user, in setting up your own woofers, as the Novice setting has more detailed directions and logical progression of steps.

The first question asked is, "Do you listen to mostly music or home theater?" This requires an easy enough answer that you enter right into the LFO software on your PC. You also have a dialogue box in the LFO software that allows you to make notes about any details of particular room settings, like the physical placement of the sub(s), etc.

You are next asked, "How many seating positions will be used?" You can toggle up to as many as eight positions. With each setting, the LFO software adds an extra chair to the screenshot, which you can drag and drop in the approximate location of the seating position.

Your AV preamp is the next factor you need to consider. Most people don’t even know that their AV preamps are sophisticated crossover systems. The Revel B15 needs to know what kind and where your crossover is going to be set. The THX standard is 80 Hz and Revel suggests you start there. You can use a different crossover if you like, but you may start at 80 for the sake of THX reference. On a Proceed AVP, like the one I use in my reference system, you can use the menu to choose the THX Standard as your crossover mode.

After you are done with your AV preamp, you will want to prepare your room for testing, which includes quieting your environment. This means that you must turn off any music and your HVAC and especially setting your system up to bypass the surround modes and stereo set-up. With these steps complete, you are ready for the Revel set-up Test Tone CD.

In playing the Revel Test Tone CD, the first test is to set the level of your main speakers to 80 dB, which requires you to use the volume control of your preamp and your SLP meter so that you are set at 80. After that, you turn the subs back on and the speakers off to measure the volume output of the woofers, making sure that they match at 80 dB as well. This will require adjustments to the volume knob of the B15. The SPL meter can be placed near your seating position.

Once the sub and the main speaker levels are set, you are ready to set the phase. This is the part where we, as mere mortals, start wildly guessing what phase setting is best. Realistically, there is no way to really tell without actually measurements like the ones you are going to get from the LFO software, even though nearly all powered subs now on the market come with phase control. With the phase adjustment on the back of your B15, you adjust the phase from 0 to 180 degrees until you find the highest level of output on your SPL.

Using the LFO software, you then scroll through the phase set-up directions and get to the Sound Level Measurements, which will come from the test CD and readings from your SPL. When you have the right screen on your LFO software and/or a legal pad and pen ready to go, you can press Play on the CD and start measuring output from your speakers and sub in your SPL meter every 1/12 octave. You can then enter in the levels that you have gotten from your SLM, based on the frequencies recorded on the CD and coming from your speakers and sub(s). Once you are done with this task, which takes only a few minutes, the LFO software outputs a graph that shows all sorts of curves that no one expects you to really understand. Even so, clicking the next button moves you amazingly into an exact layout of the back of your Revel B15, with graphic illustrations of exactly how to best EQ your sub in that location. Revel even goes so far as to hand-draw red circles so that you can see precisely where to dial in your sub’s settings.

Your first set-up may or may not be in the best location. The Revel LFO software gives you a very easy and very intuitive "save as" functionality that allows you to try this process over and over again. Remember, placement EQ is the best way to begin setting up your sub. The pros recommend that you try a number of locations in your room, so that you know you are in the best location for your environment.

The Music and the Movies
Bass is called bass for a good reason – it is the basis the other audible frequencies are built upon. The Revel B15, through its far better than average set-up procedure, provides whatever speakers you choose with a solid foundation that, believe it or not, significantly improves performance far above the frequency range of the B15. This was most evident on Stevie Wonder’s "Sir Duke" from the Original Musiquarium (Motown). While the bass guitar had a solid, round and analog feel, I was more impressed by the way a properly set up pair of B15’s helped free up the midrange, enabling the horns to absolutely jump out of my Wilson WATT Puppies. It sounded like a level of audio clutter had been lifted from my system, while placement of instruments were more obviously located in the three-dimensional soundstage.

In hopes that a pair of 1400-watt, 15-inch subwoofers would help my eternal search for pimpdom, I dropped in Philly-sound hero Teddy Pendergrass’ TP album and played the track "Love TKO" (Right Stuff Records) for some groovy soul and deep bass. Within the first four notes, I heard bass with such control and even more noticeable volume that it seemed like an entire new lower octave was now audible in my system. In fact, that isn’t really true – my reference pair of Sunfire Signature woofers are capable of nearly the same low frequencies as the B15, but the Sunfire True Subwoofer Signatures cannot play the lowest frequencies with such output. Being nearly half the physical volume of the Revel B15 subwoofers, the Sunfires had to reach their performance limit at some point, and at $1,895, they are still a steal. The Revel B15 is the next logical step up from the Sunfire, which has been the king of the hill for years, beating out subs costing many times more.

Tony Levin’s Chapman stick on Peter Gabriel’s single "Love Town" from the motion picture soundtrack from Philadelphia (Epic – import) was a very compelling test of the Revel B15s, because the Chapman stick is an instrument that is like a bass guitar, but with much different and seemingly lower frequencies associated with its distinctive sound. The resonance of the open strings is so low that you feel as much as hear the impact of the lowest notes at full volume on the B15’s.

On the same principle as the Chapman stick, the Roland 808 drum synthesizer is legendary in modern R&B and electronic music for its colon-loosening bass drum sound. My absolute bass reference is Barry White’s "There It Is" from The Icon Is Love record (A&M). I have used this track to judge bass on nearly every system I have evaluated. What I noticed with the Revel’s set-up in my system was how well the subs integrated with the dual eight-inch drivers in the Puppies of my Wilson WATT Puppies. The low notes were tight, deep, fast and loud, which made for an exciting musical experience. I was concerned that a driver this large would have trouble recoiling in time when playing back such demanding low-frequency information. The Revel B15’s 1400-watt peak amplifier and highly efficient driver were tested to their limits here and succeeded with flying colors. The best attribute of the WATT Puppies is their speed in the mid-bass and midrange, which also poses a significant challenge to any subwoofer you try to match with the costly speakers. After hearing Mr. White’s legendary demo material, I have no question that the B15’s are up to the challenge of working with highly efficient speakers costing $20,000 per pair or more.

The best the B15’s sounded was on 5.1 music material. While in stereo the B15 helped open up the midrange, a spectacular added value when investing in a subwoofer, with 5.1 music (or movies, for that matter) recorded with a specific bass track, the B15 comes into its own. The modern day Philly-sound pop supergroup Boyz II Men (DTS Entertainment – 5.1 CD) highlighted how accurate the B15’s could be on the higher frequency range of the sub. With four-part vocal harmonies and swirling 5.1 effects, the impact of the Revel subs was most evident.

Sting’s "Desert Rose" (DTS Entertainment 24 bit 5.1 CD) starts out with effects mixed to be behind you. With one of my subs physically placed way behind my listening position, the effect was even cooler. The crispness of this 24-bit 5.1 version of this hit tune was even more present with the Revels in the loop. To be even more solid than two professionally set up, kick-ass Sunfires is a major feat.

My first introduction to the Revel B15 subs was at the 2001 CES show at a private demo in the Paris Hotel Presidential Suite. The B15 and the Madrigal Imaging nine-inch CRT projector were the featured performers and did the B15 ever rock with them. With two B15’s installed and professionally set up by Kevin Voecks of Revel and Bob Hodas, I gave U-571 (Universal DVD), the featured demo DVD of the CES presentation, a run on my reference system. Holy shit. During the depth charge scene, the bass was so beyond powerful that I had to go turn the woofers down because I had my lighting fixtures rattling in the ceiling, along with CDs flying off my eight-foot-tall and 10-foot-wide bookcase that is bolted to the wall opposite the Revel Subs. At first, I thought that the woofers had reached their limits, but I was wrong. I had reached the limits of the build quality of my condo. If the goal of a home theater is to elicit strong emotions, the Revel B15’s on U-571 hit hard on the emotion of fear. They are that powerful.

The Downside
Obviously, the Revels at 20 inches squared are nearly twice the size of my reference Sunfire True Subwoofer Signatures. Logistically, this may or may not pose a problem for you, but with the extra cabinet volume, you do get more audible and tactile output.

The physical location of the Revel subwoofers is key to sonic success, but the software, as great as it is, doesn’t tell you exactly where to place the subs in your room on your first try. Trial and error are still a big part of the process of getting the most out of your B15’s. Some of the locations that Bob and Kevin tried out for me were nothing short of impossible from an interior design standpoint. Keep in mind that there is a fine line between the optimum subwoofer location and ending up in divorce court. At least with the Revel LFO software, you have the ability to receive analytical feedback on how good each location really is. I would estimate that you will need to spend at least an hour, if not two or three, in trial and error testing to make sure a single Revel B15 is in its best location. Also note that, much like building a bunch of Ikea bookcases, the more you do the set up process, the faster you get. You may for grins try a whacky spot for your B15 and find that it has better performance than you ever expected.

You do need a meter to measure sound levels in your room. Even though these aren’t too expensive at Radio Shack and the LFO software is so sophisticated that it can calibrate for most of the meters on the market, it would have been even cooler if the B15 came with a meter in the set-up package. It would make the B15 an even more complete package – not that it isn’t already the most complete high-end subwoofer ever sold.

Conclusion
The Revel B15 is a breakthrough product that costs easily $7,000 less than what it used to in order to obtain this level of performance. At 20 inches cubed, the B15 is not too large to fit in with most music and film playback systems, yet it represents the first major subwoofer breakthrough since Bob Carver’s True Subwoofer more than five years ago.

Bass is increasingly important to your music and film playback system. With 5.1 music and 5.1-plus channel DVD-Video soundtracks now a real world part of every good system, the need for high-performance subwoofers has never been more urgent. With that said, the Revel B15 overcomes the "audiophile" (I hate to even use that word) historical objections when it comes to using a subwoofer in a serious music system. Up until now, critics have been right in saying that it is nearly impossible to get the phase, placement and equalization of most woofers correctly tuned in when matching a subwoofer with a high-performance pair of loudspeakers. The Revel B15, with LFO software, test tone CD and Radio Shack meter, finally gives the music and film enthusiast the tools he or she needs to correctly integrate a sub into a sound system. At $3,000, the Revel B15 is far from the most expensive subwoofer on the market, but it may very well be the best available for under $10,000.
Manufacturer Revel
Model B15 Subwoofer
Reviewer
Genre Powered





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