Side Show
The speaker gets even more interesting when peered at from the side. There are two baffles seen housing a pair of the 15-inch bass woofers and forming the braces into which the centralized closed cabinet portion of the speaker is nestled. These are stacked quite close together in perfect alignment with a gap of 4 inches. Imagine these drivers similar to two stacked cups separated a bit; perfect replicas nearly flush. Bill calls this configuration, “differential acoustic wave launch,” and explains that they are, “digitally synchronized with the central array to maintain an ideal directivity pattern.” They are summed and time-compensated through the external crossover, but reach a null at 90 degrees off axis. Consequently the Whisper DSW, like a panel speaker, can be placed quite near the side boundary walls of a room. This technology has been used with the Whisper in rooms ranging from 50’ x 30’ to 10’ x 10’! My room is 13’ x 23’ x 7.5’, yet accommodated the humongous Helix, so the DSW was no special trick to install. Bill, who established the speakers in my room, set them 18 inches from the side wall, 56 inches from the head wall, 8 feet apart and 12 feet from my head. He prefers a more severe toe-in than I do, crossing them about two feet in front of the head, just at the edge of the listening chair. I can appreciate the sweepingly wide soundstage this creates, but prefer less toe-in, aiming the speakers at the respective Left and Right ears. At this position I perceive the center image to be more clearly defined and the soundstage deeper.
Anyone who heard the Whisper at RMAF or California Audio Show knows they can fill a sizable space. What’s marvelous is that they can also play with panache in a small room without involving the side walls and ceiling unduly. Lately, as a consequence of working with the Kingsound King full range ESL, I have taken to placing sound panels alongside the outer edge of speakers to minimize the reflection off the side walls. I find that this clarifies the wave launch emerging from the speakers as there are less side-reflected waves reaching the ear. I did not find this necessary with the DSW but I have grown accustomed to the way they sharpen the focus of the soundstage, so they remained.
The magnet of the front 15-inch bass driver sits so close to the cone of the back driver that one cannot see it from the side; the rear driver is nearly swallowing the front’s magnet. For Bill, successful bottom-end means a lot of “piston area”, a principle with which I concur. Larger cones equate to a very pleasing ease of operation, and to the ear there is no replacing this effortlessness in sound reproduction. One reason why the world’s best speakers are quite large is because they play whatever Hertz you push through them effortlessly. The DSW shares in that ability to play an authentic 20-20+ kHz even at high levels without strain.
The composition of the bass drivers is critical to the success of the Whisper series. They have low cone mass with high stiffness, more akin to a midrange driver. Bill states, “We obtain a low resonance frequency via high compliance, not high mass. We then apply an over-damped electromagnetic system to restore tautness and control.” The uniqueness of the paired bass drivers is seen in the rear pair being given a 5ms “head start” on the front pair. Then a second bass launch is added to retire the initial launch. This allows the rear driver to add oomph without a physically heavier, slower driver. When the speakers are run without the outboard crossover one can hear the loss of some precision in the bottom-end. However, this adds a “romantic”, slightly more rounded feel to the bass, which some audiophiles may enjoy. At no time was the bass sloppy such as giving the impression of being inaccurate. If through listening the owner’s heart is set on the more “lush” bass performance from the passive crossover, I imagine that Legacy would be able to instruct, or even prepare a processor program for the owner, reversing the crossover’s bi-amp function so as to have the mid and highs be active and the bass passive. I say, “I imagine…” as Bill may have good reasons for not doing so; owners should defer to his design expertise.
High Quality Bass
The nature of the bass produced by the Whisper puts an emphasis not merely on output, but the quality of the output. One might think that with four 15-inch drivers per channel the speaker should push below 20 Hz, and that perception would be correct. However, the design parameters emphasize extremely clean bass over deep bass – not overtly but subtly. Consequently, while it does not plumb the depths as deeply as the best subwoofers, the bass that is produced is tighter, cleaner and integrated with the ribbon drivers more seamlessly. A boomy bottom-end will not do for a speaker which is keyed to precision and coherence. You would have a wickedly difficult time matching bass from a separate sub mated to a panel and be anywhere near as coherent as the DSW. The best aspect of this design choice is that the bass drivers are sufficient in that they can handle frequencies down to 20 Hz. No matter what you do, you are not going to get supple, “effortless” bass from a speaker with 7- to 8-inch drivers. Even though they are open baffle, the 15-inch DSW drivers can deliver palpable bass. In order to do so you will want to consider feeding them high current along with at least 100 watts.
A private fear before taking possession of the DSW was that it would not be deep enough in the bass. I’m not a subwoofer lunatic; I don’t need the walls flexing in order to be happy. But I do demand something meaningful happening in the 20 Hz and under region. I shudder when seeing specs labeling a tower speaker as “full range”, yet going down to 40 Hz only. I don’t believe I could live with that as my reference as there’s simply too much given up. I’ve had speakers with respectable bottom-end in my room – the Wilson Benesch Curve, Von Schweikert VR-4 SR MkII, and the Legacy Focus SE (16 Hz) to name a few – and I feared that with the DSW I would sacrifice too much deep end in place of detail. Bill said the DSW would do 20 Hz, but I worried that might not be enough. I’m happy to say that with experimentation it is enough, nearly more than enough. It also is dependent upon the amplification and crossover mode.
When using the DSW in passive crossover mode I found a hierarchy in bass performance moving from the least low bass presence to the greatest with the following amps: Cambridge Audio Azur 840W (two, in mono Bi-amp), Coda CS (two, in stereo), Pathos Classic One MkIII (two, in stereo), VAC Phi 200 (two, in stereo). I used each amp with the most effective configuration for the best sound. Especially surprising was the result with the Pathos Classic One MkIII, which was run in stereo at 70wpc. A meatier, healthier bass resulted than with either solid-state amp. This I attribute to the DSW’s high efficiency, such that the harmonics of the tube amps contributed to a sense of roundness and fleshed out low frequency notes in the music.
The bass quality was such that in terms of holistic beauty, but not overall bass output, the DSW outperformed even the Helix. Part of this may be due to the arrangement of the four mid-bass drivers. The Helix has the mid-bass driver array splayed outward from each other, but the DSW places them more straight forward. Bill commented that he may revisit the Helix’s design in this instance and rework the baffle of the Helix to mimic the Whisper series. I encourage it, as I felt the grip and tautness of the bass was better with the directly aimed drivers. In general I do not prefer horizontally off-axis positioning of any drivers in speakers; I strive for the best results straight on to the listening position. I do not want to sacrifice detail and focus, which is compromised when positioning drivers off-axis.
The utilization of the Phi 200’s 2-4 Ohm speaker cable posts added smoothness to the upper-end and vitalized the 15-inch drivers so as to mate with the 7-inch midbass uniformly. Even though the DSW specs as a more efficient speaker, if running it in passive crossover mode I strongly recommend pairing it with an amp capable of driving difficult loads. Find an amp which would handle a 2 Ohm load and the DSW will respond eagerly. Here, then, is the unfair advantage for the Phi 200, as it was voiced with the Kingsound King and made to drive difficult loads. It has the raw power and adaptability to completely control the massive sets of bass drivers in the DSW.
Return to Bass City
It had been about two years since the Helix review, so I had forgotten just how powerfully the software controls the processor of Legacy speakers. Returning to active crossover operation with the Coda CS amps, it took only moments to latch onto the graph (filter) for the bass response and adjust it. Woa! Instantly I had added two huge powered subwoofers to the system!
One of the fun aspects of the DSW is the ability to hear real time the changes made. In a moment the DSW went from, “C’mon, just some more low-end,” to “Yowsa! Now that’s what I call bass!” All I had done was lift the curve from the 20-100 Hz region by 5 dB. That might not sound like a lot, but it is. Since it takes a 6 dB change to effect doubling of output, I nearly doubled the bass emanating from the DSW! Try that with any passive speaker with any amp that’s not giving enough oomph; it’s not going to happen and you’ll be stuck wanting for more. Oddly, the processor only displays down to 20Hz, but believe me there’s a lot going on below that point. Legacy uses a tight specification of 22 Hz +/- 2 dB for the lower limit of the DSW in passive mode, but in active crossover mode it’s pumping out potent bass far below that point. I think it would easily measure in the teens with a +/- 3dB spec. Remember, these are not puny 7-8-inch bass drivers, but huge 15-inch mothers which can move the air! (We love all moms of all sizes. –Ed.)
Bill was conservative in his setting the filter for the bass response, however I was not so conservative. I don’t mind a bit of cement floor-creasing bass. Case in point, one of my test tracks for low-end response is Bass Addiction’s “For Whom the Bass Tolls”, which has some ultra-low frequencies, far below most electric bass. Once I had tweaked the bass filter the DSW cranked on this piece! No passive speaker had come close to hitting the lowest notes with authority; many didn’t even reproduce them noticeably as the frequency was simply beyond them. However, in active tri-amped mode the DSW blasted the bottom such that my room pressurized even without high SPL’s. Though the walls are not interacting as much with the DSW as with a speaker like the Focus SE, which has twin 12-inch aluminum drivers per channel, the power of the DSW was unassailable. Only someone who has it as their mission to rattle the cilia from their inner ear would be disappointed in the bottom-end response.
However, the accompanying increase in output of the bass drivers put them dynamically dominant to the mids and highs. The bass was louder and taking over the presentation. A simple downward adjustment of the gain allowed me to take off 0.5 dB from them and restore equilibrium. Again, this was an easy adjustment to do. One only has to master a couple clicks of the mouse on the processor’s software to gain inordinately powerful changes. It’s terrific fun to simply play with the controls, muting channels, upping the gain, slewing the filter to see what will happen if the frequency curve is sharpened or flattened. The owner who investigates will be wowed by the flexibility and command of the signal. When tired of it you simply recall the original program and in seconds you are back to normal.
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