Zu Druid questions

I don't really understand audiophiles belittling science. That's like people who eat belittling agriculture.

Now there are discrepancies between commonly used measurements and subjective preference, but that's hardly a secret. The applicable term is "psychoacoustics", and guess what - it's a science.

If a product works and sounds good, it's because somebody got the science right.

Duke

As an analytical chemist for over 25 years, I know that there are many measurements one can make of a system, be it a chemical system, a biological system or a sound system, and that we do not have measurements that explain every phenomenon precisely. Measurements are useful to describe certain aspects of a system, but rarely do they descibe a system fully. We do the best we can with our existing tools and try to invent new ones to make the measurements the existing tools can't. New tools such as informatics and chemometrics allow us to take many seemingly disparate measurements and synthesize them into a representation of what is truly important about a system - for example, one can take measurements of a person's blood, breath, urine, etc. that are fairly useless in and of themselves and through some chemometric data treatment actually diagnose that person's health, and what diseases they may be susceptible to.

As a Zu Druid owner, I know that the published measurements seem to show something that should sound pretty bad, but the Druids absolutely SING to me. Perhaps we need some new measurements, or some ways to treat the data from the old measurements so that we actually determine the true capabilities of the system.

Ait,

Thanks for the input from your perspective - that of someone with a professional scientific background.

Here's a link that talks about an effort to better correlate measurements with perception in audio by means of a psychoacoustically-weighted metric derived from several different measurements, but focusing on the shape of the transfer function rather than on spectral changes:

http://www.audiomasterclass.com/learn.cfm?a=3651

See also Audio Engineering Society preprints number 5890, 5891, and 6888.

Duke

Duke,
Please take note that people ate before they began tinkering with agriculture. I'm not sure my correction is any more pertinient than your analogy attempt but I felt like pointing out that discrepancy.
Now, as for science, I am well aware that scientific data and techniques were applied to the creation of the Zu designs. What I am mocking is the ongoing second guessing so many of you feel qualified to apply to other peoples designs. Jack is asking for fellow members to share any experience they have with two specific speakers. He is not seeking prognostication. I've reread his post and he has not asked for opinions of what the speaker SHOULD sound like based upon an educated guess. The whole laboratory/measurement debate is stupid but if you are one who values those numbers, hell, it's your money , do your thing. I'm sure a lot of people will jump to your defense at this point and Tvad will surely scold me. Nonetheless, I maintain that the lab talk should be witheld until requested. It muddies too many discussions and hijacks too many threads.

Shardone - Some of this or that might be related to rainbows and puppydogs. If the driver is breaking up anywhere in its band I can't hear it. You couldn't either.

When the frequency response becomes very spikey above a certain frequency cone break up is often the explanation. The fall off in off axis response is probably beaming. IMHO the "whizzer" cone is there for a reason.

As Duke points out...our hearing is remarkably well able to deal with notches in the frequency response (spikes are actually much more acceptable than sustained drops)

So the break up may not be audible.

The uneven power response: Although the "whizzer" fixes the on axis to a large extent....I expect that the roll off in off axis response above 2 Khz will be clearly audible. The speaker will probably sound different as you walk from directly in front to 45 degrees off axis - this is not a bad thing - just the way it will behave and will make speaker positioning/toe-in quite important - thats all.

Duke,

I agree with you. Underdamped/high Q design is a much better explanation for the severe notch at 150 HZ. The cone will respond to cabinet resonance.

Here is another example PMC GB1 of a speaker with a similar notch.

There is a superficial similarity in the tall narrow cabinet dimensions and overal response, however the GB1 is crossed over on the tweeter much lower and therefore has a more even off axis response at higher frequencies.
PMC = 6.1"W x 9.21D x 34.25" H
Zu Druid = 10 1/2"W x 6 3/8"D x 50"H

I agree that the notch at 150 Hz will likely be inaudible - many rooms may have sharp notches like this anyway from wall reflections/modes - so no big deal.

However an underdamped design will differ quite audibly from a critically damped design. As you suggest, longer oscillations in the low end may give more of a bass impression than the frequency plot alone may suggest.

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All goes to show that measurements are meaningful and do tell us something about the design and the performance.

Of course, I would NEVER recommend to select a speaker based on measurements alone. Nevertheless I would not recommend to stick ones head in the sand and totally ignore meaurements either.

Let me finish by saying Zu Druid's are undoubtedly good speakers. The high efficiency and dynamics from this design is likely to be extremely impressive even with very modest amplification power. My intent was never to bash these great speakers. Sorry if it sounded that way...but I was only trying to defend the value of measurements.