Zu Soul Superfly

Regarding the Soul Response Graph:

I had an email exchange with Sean Casey regarding the smoothness of his published Soul Superfly response graph and its credibility in the context of prior measured response of other Zu speakers, most notably JA's empirical evaluation of Essence in the Stereophile review, because the question was raised here and I didn't have a definitive answer.

Sean promised to post notes on the measurement scheme in a FAQ on Soul. Here's part of his narrative to me in an email exchange:

"Yeah, several have questioned how we have achieved such a more or less smooth amplitude response with Soul when Essence had large “problems” in the presence region as measured by JA in Stereohile. Essence is not Soul, nor Druid. But before I get too far into things, let me say that Zu uses tests and measurement technology to assist in the designing of a good sounding, to-the-max-shove, tone-rich loudspeaker.

'We use tests and measures as tools to speed the process and fine-tune what we hear or what we want to accomplish. Building a good-sounding loudspeaker is best done with the ear as arbiter of tone, using tests and measures to assist in drilling down on a problem, realizing new insight, and absolutely in matching and quality assurance systems. Amplitude response without such things as phase and group delay measures are just a fraction of the equation. Essence runs the ribbon tweeter down lower in the bandwidth than Soul. Because of this the 10" full-range driver has significant overlap with the ribbon tweeter, and because of this there will be constructive and destructive interference between them. These interferences and their graphed patterns are highly “point measured” dependent. With Soul we focus the electrical high-pass filter very high, essentially 20kHz (note impedance graph, blue trace), and also reposition phase to better match the unfiltered FRD. There is still overlap between the two drivers, but much less. And the overlap that is there is phase matched and time-aligned. The results are a much less ragged looking presence region in the amplitude graph, than JA measured with Essence. Is all this audible? Maybe, and it depends on other factors, but for sure it makes for a good looking amplitude response!"

That's the preamble to the tech notes you'll eventually see on Sean's web site but I thought some of you might like to see his initial comments now. I will say that Sean's explanation regarding reduced overlap between FRD and supertweeter, plus the attention to phase-matching the overlap that's present, corresponds to what I hear as a distinct cleaning up of the midrange through top-end anomalies remaining in the Druid 4-08. When combined with the sharply-improved bottom end and the overall increase in dynamic aliveness, Soul Superfly comes out in all ways a better speaker than its older brother.

Phil

Avonessence: I have druids in standard matt black, which may be similar to cosmic graphite, and i think they look very nice.

Phil: Did not mean to open can of worms with my question. And let me stress again, I do not care too much about the graphs, and I very much like Zu for tone and dynamics.

Better integration with supertweeter would definitely help with freq response in HF.

But I do not think it tells us about 60Hz-200Hz! This though is being ridiculous as in room measurement at seated position is what is important here and that will vary room to room.

And I appreciate you looking into this, and Sean for clarifying! Sean is one of the good guys for sure.

Zanon: When I first heard the Zu Druids they were in the same Matt Black, and they do look nice, but when you hear that sound come out of them, the fit and finish become secondary to me.
My first pair of Druids were in gloss black as are my current Essence speakers (there was no difference in price to us on this side of the pond at the time, where there is now), if it were the matt black or the cosmic carbon I would be happy as it is a reasonably neutral colour, and the performance of the Zu speakers make them disappear visually to me.
I think any paint finish/colour (within reason) on the Zu speakers looks very good.

In addition, Zu offering to do other customized finishes is something that we do not find with manufacturers in the UK. The manufacturers in the UK are a bit reserved when it comes to finishes.

Some of us have to factor in the WAF regardless of our own views on the subject. Left to my own devices it'd be Ferrari Red but there are other considerations. I've owned one pair of speakers for 20 years and my intent is that this next pair will be in situ for a similar period. Will I be in the same house with the same decor by then? Who knows? What I do know is that my hobby is indulged subject to WAF and that I myself want something acceptable to look at when they're not playing music. As soon as Zu get more pictures up and, better still, I get to dem a pair then I'll make a decision but not before.

Mike

PS: Phil, what sort of music have you listened to on the Soul and what insights did it give you?