Zu Tone, Druid, and Definition Speakers-Listening Impression

jcoat007 · « **Reply #20 on:** 30 Aug 2005, 12:04 pm »

Quote from: 213Cobra

JCoat,

You seem to like meaty solid state amps with finesse. If you want to emulate the F2 but with more drive, perhaps consider the Channel Islands D100/D200 and the Monarchy SM70 Pro monoblocks. Certainly, Aleph is a good place to start too. I like Adam and his speakers yet I am mystified why he likes that Rogue Zeus. It wasn't just a Druid/Rogue problem -- the inertness of the amp spoke through all the Zu speakers. OK, maybe mystified is too strong a term. Adam likes punch and the Rogue is punchy, an ...

I have been thinking about the D100/D200. Have you heard them?

I just missed an opportunity to buy some Dodd Audio 120 Monoblocks. I think they would have been nice to try out.

There is a used Rogue Zeus on Agon right now, but with all the comments here I'm not going down that road.

tomahack · « **Reply #21 on:** 1 Sep 2005, 03:29 am »

This is a FR measurement of a Druid from 2 meter. Microphone measuring position: center of tweeter. Outch...

Russell Dawkins · « **Reply #22 on:** 1 Sep 2005, 03:38 am »

I thought it was well understood by now that this curve is completely irrelevant because it was taken with complete disregard for the requirement for critical tuning of the bass port by proximity to the floor. The distance from the bottom of the speaker plinth to the floor is critical for the performance of the Druid in the bass range, yet this (old) response curve was made with the speaker suspended in the air in an anechoic chamber.
Russell

_scotty_ · « **Reply #23 on:** 1 Sep 2005, 04:50 am »

Of much greater concern is the drivers behavior above 500Hz.
I strongly doubt that anyone would consider this acceptable.
The cone break-up modes can be very clearly seen starting at 2kHz.

miklorsmith · « **Reply #24 on:** 1 Sep 2005, 02:12 pm »

Having owned the Druids, I can tell you they sound nothing like that graph. They sound smooth and even, and hella dynamic. If that graph honestly shows what the response curve of this speaker is, graphs are meaningless.

mvwine · « **Reply #25 on:** 1 Sep 2005, 04:03 pm »

Isn't the discussion here about the Duid Mk 2? The graph above is from 2002 - the original Druid.

Also, looking at a measurement and saying "that can't SOUND good" is a bit backwards, isn't it?

BTW, I have never heard the Druid, but am intrigued by the design and the comments of those who have.

JohnnyLightOn · « **Reply #26 on:** 1 Sep 2005, 04:10 pm »

I think these graphs are interesting and wish I understood them better. But what's also interesting is that I rarely (if ever) see a post from someone who has both analyzed the graph and then also reported that they heard the exact problem they suspected from the graph in person. Usually, it's someone looking at the graph and pronouncing the equipment flawed, without having ever heard it to verify.

miklorsmith · « **Reply #27 on:** 1 Sep 2005, 04:57 pm »

The current iteration is Mk4. I think that graph was based on the Mk2. Whichever version, it wasn't the current model, though the overall vent design is similar. I would expect the current speaker to fair badly in those test conditions too, as the recommended (required) vent-to-floor spacing was utterly ignored. They treated the speaker as a conventional BR enclosure, which it is not.

The basic premise of graph-citers is "flat is good, crookedy bad". I don't use them, I only comment on what I hear. I agree that even response is a goal, and lots of speakers have basically even response. Where others fall down and the Druids excel is in speed and dynamics. They make others sound boorrriinnngggg.

Sadly, mine have gone away. They've been sold and it will be a bit before the Definitions arrive. Sadness. I am back to the BR Fostex 206E's, which have exceptional dynamic articulation but a ragged response curve. Put the right music on and it's sublime. Choose wrong and the ears will pay.

G.ear · « **Reply #28 on:** 1 Sep 2005, 06:34 pm »

Well, gentlemen, let's eliminate the FR depicted in the graph below 500 HZ and look at the FR graph from 500 HZ on up. As irrelevant as it might be, best case scenario for this older speaker is + or - 5 db, and that is hardly "accurate" by any modern day standards. I am perplexed by the fact that the manufacturer has been critical of how the measurements were taken, declared them as imappropriate and ill conceived, and yet has not chosen to publish a corrected or proper FR plot to backup their assertions.

mvwine · « **Reply #29 on:** 1 Sep 2005, 06:53 pm »

Mk4 vs Mk2, ah well, in any case an out of date graph, and it appeared that the reviewer did not hear a problem with the (earlier model) speaker.

It's been my experience that we listen first, and use measurements to try to understand what we hear, not the other way around.

BTW, where is the graph that measures "dynamic capability"?

G.ear · « **Reply #30 on:** 1 Sep 2005, 07:53 pm »

Yeah, just where the hell is that graph? Don't get me wrong, mvwine, there have been many loudspeakers, amplifiers, etc. that don't exactly meansure textbook perfect that nonetheless sound quite nice. However, if accuracy is a stated goal, we can be quite certain that "accuracy" has been compromised in at least one parameter if the frequency response significantly deviates from a flat response. It always gets back to what tradeoffs each individual is willing to accept.

213Cobra · « **Reply #31 on:** 5 Sep 2005, 03:59 am »

Once again, the cited graph has been discredited and is irrelevant. The graph reflects a test done WITH THE DRUID SUSPENDED IN THE AIR. This is completely wrong for the design, as the Griewe loading requires proximity to the floor. Spacing is critical. Moreover, the failure to respect the Griewe loading affects the full range of the FRD's response. The Druid sounds nothing like that graph indicates.

Phil

_scotty_ · « **Reply #32 on:** 5 Sep 2005, 05:11 am »

Apparently Griewe loading is not critical to the performance of the Zu Cable Definition Mk1.5 as both halves operate into sealed enclosures and Zu
makes no claim beyond improved bass performance due to Greiwe loading
for the Druid Mk4.
Certainly what any Zu speaker actually sounds like will have to be determined from from listening to it's performance first hand and comparing
what is heard to the performance of other speakers whose response curves
measure flatter between 1kH and 10 Khz. I am not sure what the end result
of a ragged response curve as depicted in the graph might sound like but an
A/B comparision to a flatter measuring speaker should lead to some more information. Scotty

213Cobra · « **Reply #33 on:** 5 Sep 2005, 06:12 am »

Correct, the Definition and the Druid are completely different cabinet designs. While the Griewe chamber does achieve bass improvements and that's what's claimed for it, that is not the same as saying that ignoring the floor proximity to achieve Griewe effect has no effect on the driver's performance above the bass region.

If you look at Zu's own frequency response graphs, you will see that they do not claim the Druid to be as linear as the Definition, for the latter measures flatter and sounds that way too. However the Druid does not resemble the spectacular anomalies of the misconceived test cited in the graph in this thread, which is easily apparent when you audition the speaker.

Phil

G.ear · « **Reply #34 on:** 5 Sep 2005, 07:34 am »

Phil,

Quote

If you look at Zu's own frequency response graphs, you will see that they do not claim the Druid to be as linear as the Definition,

Where would a person go to find Zu's own frequency response graphs? If it is on their website, I've certainly managed to miss it.

Also, I just discovered a review of the Druid-2 performed by Positive Feedback Online http://www.positive-feedback.com/Issue11/zudruid.htm back in 2003, for anyone who is interested and hasn't already seen it. I'd be curious to know how that speaker differs from the Druid Mk IV? The Druid -2 retailed for $3995. It's not typical for later versions of a speaker to gain in performance and go down in price. Anyone know the history there?

Dean

213Cobra · « **Reply #35 on:** 5 Sep 2005, 03:39 pm »

Zu's response graph for the Druid Mk IV is here - at the end of the user guide:

http://www.zucable.com/media/pdf/Druid4Guide.pdf

The graph combines traces for amplitude (what you want to see, purple trace) +/- 15 degrees), reactance, impedance and phase.

Zu's response graph for the Definitions is here:

http://www.zucable.com/media/loudspeakers/DefMeasuresBasic.pdf

This graph gives separate traces for the sub-bass array, the FRD and the supertweeter. and you will see it is smoother than the Druid above 500 Hz. There is also an impedance trace.

The Definition performance is improved by virtue of using 2 FRDs and acoustically managing the tweeter's behavior acoustically with its placement between the FRDs, enabling a simpler network filter for rolling in the tweeter than must be used on the Druid.

I don't know the full history, but from conversations with Sean and Adam in which I asked the same question, Zu managed to raise performance and reduce price doing several things:

1/ they found some added efficiencies in their manufacturing methods;
2/ a non-gloss finish is now standard, limited to 2 colors -- this took a lot of cost out of the speaker relative to the Mk 2 -- gloss custom finishes are available at added cost;
3/ The base plate is now made from silver-gloss-finished machined MDF rather than 3/4" aluminum stock

There may be other factors but that's what I know. I don't know whether new tweeter/old tweeter was a wash in cost or not.

Phil

G.ear · « **Reply #36 on:** 5 Sep 2005, 05:38 pm »

Phil,

Thanks for the links. As viewed, the response curves for the Druid are for the Mk III version. Very pleased with the overall look of the FR and electrical properties. Amplifiers will like the Druids way better than most speakers. Unless I missed something, the response curve for the Definitions isn't really an actual response curve, but rather a graphic illustration of the bandwidth and crossover points of the three driver sets. How nice it would be if any speaker had the response characteristics displayed by that graphic illustration.

I was a little disturbed by the impulse response depicted for the Druid, but that could be because I don't really know how to interpret the graph. What confuses and disturbs me is the negative spike after the initial impulse along with the ringing that continues on for about another ms. The negative spike is of even greater amplitude than the initial impulse. At first, I wondered if the negative spike was due to the FRD and the tweeter being wired out of phase, but I doubt that is the case given the illustrated step response.

Out of curiosity, I went to the website of the French driver manufacturer PHY-HP and found a comparable impulse graph derived from their FR driver model H 30 LB 15 SAG. Here is the link to their impulse graph: http://www.phy-hp.com/English/Images/Produits/h30_impulse_700.jpg. There are many who think this is the finest FR driver made (right or wrong) and it is the same unit that is used in the Tonian Acoustics MLT-1 loudspeaker. What we see here is pretty much the same thing with the negative spike, so perhaps all drivers or all FR drivers exhibit that characteristic. I did note that the negative spike was of lesser amplitude than exhibited by the Druid's, but of probably far greater significance was the reduction in both amplitude and time of the ringing after the impulse. This is probably one of the most expensive drivers in the world, so one would expect it be superior in some way. Even so, pretty nice relative performance from the Druid's FRD.

The review of the Druid-2 in Positive Feedback Online stated that the enclosure was made from a graphite composite laminate wood core, and was described as a "torsion-box enclosure." The article stated that "Zu claims that "the laminate wood core combines with the graphite fiber shells to dramatically lower box resonances."" Apparently that method of cabinet construction is not currently being used. No doubt that type of construction would have been far more costly to produce, so that alone could explain a goodly portion of the price reduction as well.

Dean

ooheadsoo · « **Reply #37 on:** 5 Sep 2005, 06:46 pm »

There is always a negative spike.

The freq plot of the druids is incredibly smoothed.

Yes, the response graph on the definitions is a simulation.

ton1313 · « **Reply #38 on:** 5 Sep 2005, 07:45 pm »

FYI,

The Druid 2 version still offered Zu's B3 geometry plug, an 8 pole neutrik connector. The Druid was then completely wired with the exact speaker cable that was being sold by Zu for use in your home (WAX). The theory was that you were keeping the same structure of cabling right up to the voice coils, and not relying on sub par internal cabling, as is sometimes the case.

I did original comparisons of the Druid with both the standard spades and the "B3" plug. The plug was smoother and was a more enjoyable presentation, than the standard spade connection. However, this connection was not widely accepted, and added extensive labor to the speaker.

If you look at my Avitar, it is a photo of the back of the Druid with the B3 plug, right below the binding post.

Hope this clarifies things

213Cobra · « **Reply #39 on:** 6 Sep 2005, 01:13 am »

Dean,

Yeah, the Definition graph is presumably idealized or hypothesized in some way but it's not clear how (much). However, what is unmistakable is that the Definition sounds distinctly flatter, more neutral and accurate than the Druid, though this is a matter of degrees between two speakers sharing a common designer's perception of what constitutes fidelity in sound reproduction.

From what I understand from Zu, the Druid response graph remains representative of the current speaker. It sounds it, anyway. As noted, there's always a negative dip after the initial impulse spike and I certainly hear nothing in the speaker's performance that suggests a problem, especially compared to the tepid impulse characteristics of most speakers. In any case, I pay little attention to loudspeaker test graphs as I've found that obsessing over them seldom yields the better speaker selection when comparing a few otherwise good choices. As the PHY-HP graph illustrates, nothing perfectly responds to disturbance. The Zu FRD sounds exceptional in this respect in real world conditions.

I don't know whether Positive Feedback accurately described the cabinet construction in v2 of the Druid, or not. The box is quite strong without having to be as strong as it is. The FRD exhibts very little excursion and is very light. It isn't really whacking the cabinet with wave/air shocks very much, especially in the Druid. As I understand it the current speaker cabinet is precisely-machined MDF. Adam told me he can machine MDF to tighter tolerances than metal, which seems a startling claim on the face of it. The cabinet is then encased in a synthethic layer that adds strength and controls resonance, and the finish is applied on top of that. The same basic techniques are used on the Definition but the drivers are working into sealed chambers.

Also, apparently the Griewe model is much more dependent on precise distance between the floor and the back surface of the FRD than it is on cabinet volume, hence making the bass character highly tunable with small adjustments to the height of the Druid base-plate off the floor.

My Mk4 Druids are unusual, I suppose, having been gloss-finished Mk2s factory upgraded to Mk4. As a result, I have both the B3 connector/wiring scheme and the Cardas binding posts. The speakers were wired internally with Ibis cable and I have Ibis cable from amps to Druids. I haven't been able to listen to Ibis cables through the Cardas binding posts or non-Zu cables through the B3 connector so I can't corroborate Zu's specific claims for the B3, but certainly Ibis + B3 made the largest unconditional quality improvement attributable to speaker cables I've experienced.

You can talk yourself into or out of anything in audiophilia. Now that I've heard Tones and the Method sub, along with the Defs and Druids I own, I can say clearly that Zu speakers as a line are a real advance; the real deal. These speakers knock you back even more for what they don't have than for what they do. Their lack of fatigue and other distress-inducing anomalies all too common to even the most rarefied hifi gear take more time to recognize than do their transparency, naturalism and dynamic consistency top to bottom. It's great if you can hear them in a Zu roadshow or other event, but there's very little real risk in trying them, especially based on the information you can tap in the Zu community.

I am 6 months into owning both my speakers now. Speakers being grossly imperfect relative to their mission, in the past, even if I ended up keeping speakers for several years, within 6 months of owning a pair I was analyzing my dissatisfactions and plotting a path to the next move. I don't even think about that for an instant now.

Phil