Zu Soul Superfly

Definition has always measured quite flat and yet it is a deeply toneful speaker. Flat-measuring speakers that get that way through complex crossovers with steep driver contouring do tend to sound like anything *but* flat and are irritating for many people (like me) to listen to, for other reasons than measuring "flat." It's all in how the designer gets to "flat" on the graph.

The Druid in some respects ruined Zu's credibility on measurements because Zu didn't measure it early, while some reviewers did, not understanding how to measure its real-world use. The infamous Canadian review of early Druid, in which the publication complied with Canadian practice of measuring a speaker suspended in mid-air, yielded a disastrously ugly graph that had nothing whatsoever to do with how a Druid sounded in a real residential room when properly set up. But the empirical audiophile brigade couldn't (or wouldn't) grok the fact that Druid's partial Griewe loading requires placement on a floor (you know, the way you'd actually use the speaker) with some attention paid to a fussy floor-to-plinth gap, in order to sound and measure right. Since then, Zu owners haven't cared a whit how the speakers measure, and Zu critics won't bother hearing them, or grant that they can possibly sound good, let alone great.

Superfly sounds like it measures, objectively. But since it gets to a reasonably flat graph without a crossover and most of its range is produced by one coherent driver, it won't sound like most flat-measuring speakers sound.

As the graph indicates, Superfly will be revealing. It is a bit more "accurate" speaker than Druid 4-08. A grungy amp will sound grungier on Superfly than on Druid. But the high impedance makes most amps, even grungy ones, sound better than they normally do, and not driving a crossover before the voice coil puts them on better behavior too. So Superfly is both revealing and forgiving, all things considered. But conversely, an excellent amp will be even more appreciated on Superfly than on Druid 4-08.

The changes over Druid aren't that small, given how much the FRD has been massaged. The full Griewe model seriously improves and extends bass, but it also affects the driver's performance well into the midrange. The cone and motor changes to the FRD make it considerably more vivid. The high-pass filter to which the supertweeter is wired is both more linear and cleaner owing to the selected components. And the cylindrical phase plug markedly linearizes and improve dispersion of the FRD's high-frequency output from the whizzer. What a lot of other designers would try to upgrade through multiple drivers and a more complicated crossover, Zu has attacked by refining the main driver's capabilities directly.

A frequency response graph is only a facet of a louodpeaker's performance indicative of an ability to transduce convincing music. It tells you nothing whatsoever about tone density, timbral acuity, dynamic aliveness, transient speed, spatial projection, phase coherence, or other non-frequency fidelity factors. And since the speaker's interaction with actual room and amplification factors aren't at all captured by frequency response measurements, you can safely limit how seriously you take such representations of performance.

Do I believe "those numbers?" Numbers imply a precision to speaker performance that's not remotely sustainable in actual deployment into a customer's system. It's not that I don't believe them. I believe Zu attained that curve. I just don't think it's relevant. Superfly sounds neutral and extended in the ways Zu's graph suggests. That's easily the least influential reason to buy the speaker over the myriad other speakers that also measure "flat." in the same price range.

Phil

cobra:

sorry to join in the folks peppering you with questions, but here is mine:

i ordered a pair of mk-iv '08 druids a few years back. i loved just about everything about them. the sound, presentation, etc. i was pretty new to the high efficiency side of the hobby, but even got drawn into that. i could not, however, really get the druids set up in a way that worked in my room. i worked with a number of the folks there to try and get an ideal set up where i wanted them to live but fell flat. selling my druids was one of the few 'regrets' i had. even though i ended up with speakers that worked better in my room, i never like the sound as much.

you alluded to the souls being easier to set up. is it mostly driven by the design? i have since completely redone my room, changed the floors and walls and added treatment. just about everything sounds good in here now. are the souls that much less sensitive to placement? if so, i think i'm sold.

and, thanks for all of the impressions/thoughts/insights.

tim

phil:

yes, i know that infamous graph, but i am not a graph-only guy (or i would not have druid).

i was thinking of essence stereophle graph which was pretty ragged too. soul looked so flat i cannot believe it.

TIM, try get better sound by jim smith. great book

Tim,

Can you explain the conflict between Druids and your room? What did you hear that led you to believe you couldn't "really get the Druids set up in a way that worked" in your room? Yet you ended up with speakers that worked better but you never liked the sound as much?

What didn't work about the Druids?

There are three things about the Soul that should make placement easier and more plug'n'play:

1/ Unlike the Druid's fussy floor-to-plinth gap adjustment, Soul is fixed gap on spikes and unless you have some exceedingly tall and stiff pile carpet, I can't see running into any gap problems. The tapered finger vents on the bottom of the cabinet do not need precise location above the floor for the Griewe model to work correctly.

2/ For some people, Druid's acoustic center was too far off the floor and the FRD radiated too much energy unimpeded by furniture and buman bodies directly to opposite surfaces. Druid also had a bit of directionality that gave it a narrower sweet spot than Soul. Soul's greater horizontal dispersion makes it easier to get good sound throughout the possible listening positions in a room. Soul puts the FRD less than 3' off the floor and its output is angled slightly upward. The acoutstic vertical center of the soundstaging is more natural for many people when seated, and its output is more in the dissipating and diffusing line of sight to the normal contents of a room., which is good.

3/ Soul has fewer aural anomalies than Druid, and bass is more extended without rumbling deep into the zone most rooms handle poorly. It's simply a more neutral speaker. The buying public at large seems highly sensitive to perceptions of bass output. Soul gives everyone less to argue about in that respect. It goes deep enough but not so deep as to cause real trouble. And its bass character is toneful, highly-defined and textured.

Phil

Zanon,

I (or you) would have to ask Sean Casey about specifics on his frequency response/impedance graph. I haven't even discussed it. Perhaps the data informing the graph was normalized. Of course, to me, Soul *does* sound smoother than Essence, the "least Zu" speaker so far. But I've said straightforwardly I've considered Essence inferior to Druid 4-08 since Essence launched. I certainly never for a second considered giving up my Druid 4-08s for Essence, but I will replace them with Soul Superfly. But I understand why Essence appeals to a broader population.

There's a difference between ragged and wrong. I don't recall the Stereophile data graph on Essence (though I do remember something like JA conceding that it sounded to him as Art Dudley described, regardless of how it measured) but ragged response that shows short bandwidth abberations against a backdrop of general octave-to-octave balance can sound just fine and convincing, as opposed to a speaker with smoother curve but clearly visible octave-to-octave dysfunction, which can sound completely wrong.

At the end of the day, Zu's graph isn't actionable to me one way or another, but I've had the opportunity to both follow the speaker's development and hear at length in final form. It *sounds* about as smooth as Zu represents, but in a real customer setting it would never measure that way.

Phil