Music in the Round #21 Page 2

Since then, from the home-built Altec A-7s of grad-school days, through homemade transmission lines, and on to the B&W 802Ds I now enjoy, almost all of my speakers have been full-size floorstanders. Somewhere in there I had a lingering affair with a pair of Stax ELS-F81s; they were beguiling, but drove me in desperation toward the bottom end, and to one ill-mated subwoofer after another. Nothing worked right—not until the rise of home theater and multichannel sound did the science of subwoofing flower.

Here's why. Multichannel sound means multiple speakers, and few domestic living spaces or spouses will tolerate five Wilson Audio Alexandrias. More significant, placement for best imaging and tonal balance is rarely ever in agreement with placement for best bass extension and linearity. With only two speakers, we have a shot at finding an effective compromise, but placing five or six speakers introduces many more choices—and many more ways to screw up the conflict between imaging and bass.

Now, you might think that three B&W 802Ds supplemented by a pair of 804S surrounds would need no help at the bottom end. Not so. John Atkinson's measurements of the 802D (see Stereophile, December 2005) show its woofer response rolling off below 30Hz, while its port response is pretty flat down to 20Hz. The woofer response, however, also is responsible for the broad elevation in the 100Hz area, and I co-opted the Speaker Boundary Interference Response (SBIR) to help. I moved the left and right 802Ds laterally rather farther apart than I had used for two-channel listening. When I toed-in the speakers a bit more toward me and put some absorption panels on the sidewalls, the imaging became spacious and precise, with or without the center speaker. With the woofers now only 34" from the sidewalls, SBIR reduces the in-room output to about 100Hz, flattening the overall response. The bass is cleaner and unbloated, though at the price of weight at the very bottom.

Enter JL Audio's Fathom f113 powered subwoofer. Over the years, I've heard lots of bass from JL Audio—sometimes voluntarily, as I cruised the mobile-audio venues at a Consumer Electronics Show, and sometimes involuntarily, as annoying motorists cruised by my house—so I knew at least something of JLA's reputation when I heard their demo at the 2005 CEDIA Expo. It was the most intense bass experience I ever hope to have. Five subs were used in the small demo room, and the sound was palpable and apparently limitless. I immediately requested a Fathom f113 ($3300 in gloss black) for review. There is a larger JLA sub, the Gotham g213, but I would have been unable to move or accommodate it. In retrospect, the smaller Fathom f112 might have been all I needed.

The staff in my building is pretty easygoing, and probably gossips about the big boxes that stream in and out of our apartment, but this was the first time they actually said anything. The f113's relatively small carton was described as "really heavy," and at 130 lbs, it really is. JLA's unpacking instructions are to be taken literally: Get help, and unpack near the final location. The f113 is a sealed, beautiful near-cube with squishy, sticky feet. Moving it is like moving a Sumo wrestler.

I had to rely on JLA's guidelines to position the f113—moving it around the room, or even placing it temporarily at the listening position while I took measurements, were out. It went against the front wall, behind the B&W 802Ds and about a third of the way from the corner. (Someday, someone will combine an auto-EQ sub and a Roomba so that the sub can find its own damn sweet spot!) Between the large heatsinks on the back (needed for the 2500W peak output of the f113's class-D amplifier) are XLR inputs/output (for daisy-chaining another sub), RCA inputs, switches for master/slave and grounding, and the IEC power connector. All the user controls are on the front, under the removable grille—you don't need to move the sub to adjust its settings. Thank goodness.

Pop off the f113's very sturdy grille and you'll see a 13" drive-unit with a prominent OverRoll surround that permits huge cone excursions. This sophisticated driver, made by JLA, has many other specializations for this application that are described on the JLA website. The panel across the top of the front provides all the controls and connections for JLA's Automatic Room Optimization (ARO) software and for the signal-processing features needed for integration and tweaking.

ARO couldn't be easier to use. Just plug in the provided microphone, place it at the listening position, press the Calibrate button, and stand clear. ARO checks for adequate signal levels, then plays a series of tones as it measures the room's response. I was immediately impressed with the tightness and power of the small f113 as it progressively rattled my room's cabinets and clocks. A steadily illuminated LED tells you when ARO is done. Comparing the performance of the f113 before and after ARO, I found that the extreme bass didn't so much sound different as that the presence of the sub, as a discrete source in the room, disappeared. Either way, it was powerful and taut.

A quick check with the GoldLine TEF-25 acoustic analyzer was revealing. The f113's uncorrected pre-ARO output—referred to 80Hz, the standard bass-management crossover—was down only 5dB at 15Hz, but was +3dB from 25 to 40Hz, with a –11dB crevasse at 45Hz. Post-ARO, 15Hz was down only 2dB, 25–40Hz was flat, and there was only a crevice of 4dB at 45Hz. Variation from 15 to 80Hz went from 13dB to only 4dB!

This is quite remarkable linearity. When a conversation with JL Audio revealed that the ARO is a single-band parametric equalizer, at first I was disappointed. However, remember that a subwoofer as potent (and expensive) as this will probably be used with decent speakers, when it will cover no more than about two octaves. Heck, with the B&Ws, I should have set the bass-management crossover at 40Hz! Nonetheless, even with the 80Hz crossovers in the Bel Canto and Sony disc players, the transition was almost inaudible, the quality of the bass in no way inferior to running the B&Ws as Large speakers (well, they are!) and feeding the f113 only the LFE channel.

As for my subjective reactions, Penderecki's Credo sounded even more granitic in the bass with the Fathom f113 in the system. Even the double basses in Hunt Lieberson's Handel disc were more detailed. But these were only hints. A peachy (and punchy) new recital, Phantomes: An Organ Spectacular (SACD, Oehms OEH-606), opens with J.S. Bach's Toccata and Fugue in D Minor, played by Harald Feller. The weight and power of the instrument and the ripe acoustic are marvelous in 5.0 channels. However, when I told the SACD player that the 802Ds are Small and to redirect the low bass to the f113, the effect was physical. I felt as well as heard the pedal tones as throbbing pressure waves. But let's not stop there. I downloaded a fireworks WAV file and paid careful attention to the accompanying warnings. The f113 never cried Uncle, even when I turned it up to levels of 10–50Hz energy that approached pain. This bass freak's eyes glaze over at the thought of what its big brother, the Gotham g213, might do...

Small as it is, JL Audio's Fathom f113 makes a powerful and musical contribution to the bottom end, even in the context of an already full-range system. Its setup is sophisticated and simple, and its small size and beautiful appearance should make it welcome and valuable in any system.

Stop press!
The most impressive demo at Home Entertainment 2006 last May confirmed the value of acoustic room treatments. With identical equipment and recordings in paired rooms, Rives Audio, RealTraps, and RPG treated only one room, leaving the other as the hotel designer's had intended. The difference between the two was astounding. Because RealTraps' Tri-Corner traps seemed the perfect fit for the lower rear corners of my weekend room, I wheedled the prototype pair from RealTraps' Ethan Winer and slid them into position behind the stands that support my Paradigm Reference Studio/20 loudspeakers. Wow! These small equilateral triangles, 32" on a side and costing $249 each, had a bigger impact on the sound than I had expected. The low end, as already set up and EQ'd with care, became overpowering. I had to cut the level to my Paradigm Servo-15 sub by about 6dB to restore a musical balance. Measurements and more descriptions to come, but for those of us with spousal and decorative constraints, RealTraps' Tri-Corner Trap is a notable product.

Next Time in the Round
Yes, I did promise coverage of NHT's Controller preamplifier-processor and Power5 power amplifier, but the first pair was damaged in shipment, and I've just now successfully installed a working pair. Also in hand (any further reporting delays will clearly be my responsibility) is the new AudysseyPro System EQ. This is a dealer-installed product, but Audyssey has provided me with the complete package of hardware and software, with which I will be wrestling as well.

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