Velodyne ULD-18 & ULD-15 subwoofers Page 4

Over the next few weeks, I trotted out all the "deep bass" warhorses I had collected over the years. I did all the usual subwoofer tricks—rattled objects in the room, flapped pants legs, heard the air shudder with 20Hz organ-pedal notes. And yes, I listened to diesel-engine track noise and cannon blasts. But I soon used this new system to listen to music, returning to my favorite pipe-organ music, long ago relegated to the upper shelves. It was a pleasure to finally enjoy these records. I started with the white vinyl, direct-to-disc Virgil Fox recordings of the Fratelli-Rufatti organ in the Garden Grove Community Church. Next came Also Sprach Zarathustra (Time Warp, Telarc CD-80186). The opening 32Hz note had a rock-solid, locked-in quality without sounding artificial or too airy. The drum crash on Dafos (Reference Recordings, side 2, cut 3), recorded by Keith Johnson, captured the impact of a massive drum falling over on stage. The sound shook my floor but did not break up or cause the amp to clip.

But there was more, and this goes beyond simple subwoofer bone-rattling stunts. What did the ULD-18 do for my system as a whole?

First, the ULD-18 integrated beautifully with the Quad ESL-63s I was using as main speakers. Jim Lee, Vice President of Velodyne, warned that the ULD-18 would "overpower" the Quads with its greater dynamic range and potentially more aggressive character. The electrostats just wouldn't play loud enough to match the ULD-18, he feared. I had worried that the ULD-18's 18" woofer, even with the servo mechanism, would be slower and have a very different sonic fingerprint from the ultrafast, transparent, and recessed ESL-63s. The resulting Velodyne/Quad personality clash would mar both.

Not so. Rather, the integration was seamless and changed the overall character of the system in a synergistic, beneficial direction. The Quads opened up as the soundstage widened and deepened, and imaging took on a solidity that I had never heard before. The Velodyne also improved, for it seemed to speed up, as if the Quads sharpened the leading edge of deep-bass transients. The bass notes were integrated in time and space, and the speed of the electrostats really joined synergistically with the power contained within the bass envelope, helping to define it. The timbre of deep-bass string tone was true. All the while, there was no sense that the music was coming from different loudspeakers in different locations.

The information-enhancing effect was just as evident on sources that contained no 16Hz pulses, just the normal frequency spectrum of music. The bass line of the plucked bass in "Guantanamera," on The Weavers—Reunion at Carnegie Hall in 1963 (Vanguard VSD-2150) suddenly was there, when it had been totally absent on the Quads. But even more interesting was the fact that, for the first time, I realized that the bass was probably either a washtub bass or a foot tapping, not a formal double bass. The bass line on the jazz piece "Going Home," from the LA Four CD album of the same name (AI Music Company, Tokyo; East Wind 32JD-10043), was palpably real, because all the overtones were there.

Second, the dynamic range of the Quads was greatly extended. Although this is far from a scientific description, my Levinson ML-7A's volume control could be pushed from 11 AM to 1PM, which formerly would have guaranteed Quad shutdown. The Quad ESL-63s, though very low in distortion and very fast, tend to be dry and analytic on orchestral music. Mounted on Arcici stands, they gave beautifully accurate but distant portraits of orchestral pieces. With the ULD-18, the Quads finally had balls, becoming punchy and aggressive, but still transparent and very fast. Zubin Mehta's Le Sacre Du Printemps (Los Angeles Philharmonic, London CS-6664) suddenly had solid, punchy dynamic midrange and fast, trenchant bass that gave a full "goosebump" effect. The dramatic power and hair-raising suddenness of the Synclavier II digital synthesizer in the "Ascent" opening of Telarc's Time Warp was all there, with a new fury and stunning presence.

Third, the Quad/Velodyne marriage made pipe-organ music enjoyable. As noted earlier, I had given up listening to the "king of instruments" in my system. In churches or concerts, I loved the contrast between the purity and song of the upper flutes contrasted with the shuddering solidity of the pedals. In my room, the upper notes were harsh and bright, particularly with dynamic speakers; the recent renovations brought in new furniture, and the tonal balance softened. Other subwoofers had not moved much air and certainly hadn't coupled with the room, locking it in and moving me as with the real instrument. Not so with the Velodyne—I was there!

A good example of the quantum leap in organ-music quality came during a comparison of two organ recordings. The first is an Ormandy vinyl recording of the Saint-Saëns Symphony 3, "The Organ Symphony," with E. Power Biggs (Columbia ML 6469). This had been my standard record for auditioning subwoofers, because the bass was so easy to hear. On the Velodyne, the 25–40Hz region sounded boosted, over-equalized, and as if it had been recorded separately, in a different studio and at a different time. Biggs's music overpowered the orchestra and was bloated, artificial, and sounded like an out-of-tune synthesizer. The opposite was true of the recent Dorian CD of Jean Guillou playing a transcription of Mussorgsky's Pictures at an Exhibition (Dorian DOR-90117). The 32' pedal notes of the Great Kleuker-Seinmeyer Organ of the Tonhalle in Zurich were reproduced with power and speed. They shook the room, but did not pollute the wonderful sounds of the instrument's flute and trumpet stops.

Subwoofer comparisons
These listening results were suspect—I just couldn't believe that the ULD-18 had such power, and, at the same time, did not interfere with the midrange. To check, I auditioned two other subwoofer systems in the same area of the room next to the Quads. First came the $4700 Celestion System 6000 (dipole woofers with SL600Si satellites, electronic crossover and equalizer), a system that reached the "B" rank in our April "Recommended Components"; the highest assigned to a subwoofer so far (no subwoofer had made the "A" rank—yet!). JA shipped me the same 6000 DO had used in his marathon subwoofer review, complete with metal spikes!

The 6000 is a very solid, heavy, dipole system, and I mated its crossover to a VSP Labs MOS 150Wpc stereo amp via Levinson speaker cable, and sent the high-pass output to either the Quads or the 600SIs. Both Quads and 600Sis were colored by the Celestion crossover unit; this became clear when I coupled the 600Sis with the Velodyne system, the resulting sound being more open and not colored.

How was the bass? Compared with the single ULD-18, the twin 6000s gave "Quality Bass," to quote DO, which meant well-defined but faint bass notes. No shaking and quaking or floor-flexing here! I even switched off the main amp to make certain the 6000s were playing! Switching from the Velodyne, the overall system gain on the preamp had to be reduced markedly or the VSP amp clipped and the Celestion 6000s distorted (clunked!) on Songs of War and Peace.

The ULD-15
I then tried both Quads and Celestions with another Velodyne product, the ULD-15. The 15" subwoofer produced much more powerful bass than the System 6000, and was equally as fast and powerful on many selections as the '18. The '15 integrated particularly well with the SL600Si, in many ways better than the 6000 system did! But its sonic fingerprint was quite different from the '18's. Hall had explained that the '18's larger enclosure allowed for higher spls at lower distortion because of fewer nonlinearities in compressing the air within its enclosure. In fact, I could hear the '18 less than the '15—in many ways it matched the Quad's own reticent style. While the '18 took on a Quad-like transparency and speed, the ULD-15 was punchy, dynamic, and forward. In effect, the '15 insisted on showing its own personality. The soundstage shrunk slightly, and the depth diminished. I missed the ease and the openness I had heard with the 18". Even though the ULD-18 has a bigger cone, it actually seemed a better match for my planar speaker than the smaller ULD-15.

The ULD-18 works wonderfully with the Quads, as if the two had been designed by the same hand. If you own ESL-63s, I would wager that you have never heard their full potential until you have heard them with the Velodyne ULD-18. Is this a specific synergism not to be found with any other speaker? I doubt it, for the Celestion SL600Sis showed the same boost in transparency, openness, and effortlessness when integrated with either Velodyne. One should expect an improvement from most speakers if the troublesome bass region is finessed; all the more true for the Celestion and Quad loudspeakers, known for their bass limitations. The Velodyne is doing what a subwoofer should do: clean up, not muddy, the midrange.

Well, I guess Anthony H. Cordesman was correct. If a loudspeaker really produces deep bass, you'll hear it easily, and not any amount of tweaking will turn a subwoofer with good definition but insufficient quantity into a well-controlled powerhouse. All my former fussing with different amps, different electronic crossovers, and different room positions didn't help as much as just plugging the Velodyne into the system. Yes, room placement was critical, but after an afternoon of moving the 105-pound giant around, it ended up in the same place it started—between and behind the Quads. The ULD-18 achieves "a large-signal extension to 20Hz," the very criterion being reserved by JA for a Class A rating in "Recommended Components," performance that had previously only been found in the price-no-object IRS Betas, WAMMs, IRS V, and Synthesis systems.

I began this review hoping that I would be able to recommend which system, which room, and for which music the audiophile might choose the ULD-18 over the much more economical ULD-15. Would the ULD-18's $800-higher price and 48 extra pounds be justified for larger rooms, which can be a decorator's biggest challenge? The answer is simple: The ULD-18 is justified if you must have the best sonics throughout the entire range of your main speakers, particularly if they are planars or electrostatics. The ULD-18's HGS system and motional feedback keep distortion low. This translates into a lack of coloration and superior speed that has no equal in the current add-on subwoofer market, to my mind. For once, an add-on subwoofer actually delivers true subwoofer bass with high quality and high quantity at the same time—the ULD-18 lets your system sing!

Velodyne Acoustics, Inc.
345 Digital Drive
Morgan Hill, CA 95037
(408) 465-2800

Staxguy's picture

What a great, great article!

Well, and informatively written.

Thank you, editor, for re-publishing!