Definitive Technology speakers

Artisan Fan · Oct 7, 2009

Originally Posted by milosh

That link says nothing about converters performing badly due to vibrations.

Roy Gregory of Nordost and Steve Elford of Vertex AQ gave a PPT presentation at the Rocky Mountain Audio Fest I was at this weekend. They have engaged British defense contractor Acuity Products to create a new measurement methodology. Essentially they have measured time-based errors of CD players before and after three tweaks: better AC cables, better platform for vibration control, and Quantum conditioning which improves magnetic fields or something like that. The graphs they presented will soon be in a white paper and possibly an AES paper. The link above shows the improvement after the vibration control and two other tweaks. The text notes the improvement.

In this second graph we have reproduced the difference, or error graph, between the original track and the output of our CD player when it is just sat on the test bench and connected with ordinary leads. Again the scale is not easy to see but the amplitude of this error is actually about 8 percent of the amplitude of the music signal (the scale of the error graphs has been expanded so that you can see the graph easily).

Dmax, also read the link. It clearly shows the improvement of cables alone. In fact, they demonstrated the benefit of fine cables separately which is also how they conducted the tests.

Douglas · Oct 7, 2009

Based on this thread, I just bought a pair of Magnepan 1.6s. I am running them off my Onkyo receiver and Sony Discman and they are the greatest speakers of all time. FYI, I have the Discman sitting on carbon-fiber scraps I found at a junk yard next to a race track, and myone-nine copper lamp cord never touches the ground - I filled cardboard boxes with packing peanuts and coiled the wire inside.

A Y · Oct 8, 2009

Originally Posted by Artisan Fan

Dmax, also read the link. It clearly shows the improvement of cables alone. In fact, they demonstrated the benefit of fine cables separately which is also how they conducted the tests.

That test is problematic, and inconclusive. The graphs are way too small to read the units off them, especially the time axis. That's important so the reader can determine the frequency range of the error signal --- it is trivial to produce different error signals in the RF with different cables, and even just different orientation of the device. RF is often a 2nd- or 3rd-order effect when it comes to audible consequences.

Speaking of the error signal, the most egregious flaw of the test is that there is no explanation of how they derived the error signal --- the subtraction of the output of the player from the original signal. As anyone who has ever tried to do this will tell you, there are a million ways to screw it up and produce false positives. Until they provide a detailed explanation of their procedure, this test doesn't say anything useful.

--Andre

Artisan Fan · Oct 8, 2009

Originally Posted by A Y

That test is problematic, and inconclusive. The graphs are way too small to read the units off them, especially the time axis. That's important so the reader can determine the frequency range of the error signal --- it is trivial to produce different error signals in the RF with different cables, and even just different orientation of the device. RF is often a 2nd- or 3rd-order effect when it comes to audible consequences. Speaking of the error signal, the most egregious flaw of the test is that there is no explanation of how they derived the error signal --- the subtraction of the output of the player from the original signal. As anyone who has ever tried to do this will tell you, there are a million ways to screw it up and produce false positives. Until they provide a detailed explanation of their procedure, this test doesn't say anything useful. --Andre
Andre, You have not seen all the methodology and resulting evidence presented at RMAF. Trust me, this test will meet the highest standards of scientific inquiry. They used one of the foremost sonar and sound specialists in the U.K. As for the error signal, it was based on developing a protocol where everything else, minus the treatments, was kept the same. In the RMAF discussion, they proved this several different ways to capture different errors. It will be more obvious once the white paper is put out. I have reached out to Steve Elford and Roy Gregory to see if I can get some PPT slides to share. The graphs are quite large and visual when you see the full presentation. One of the bigger results was the measurement of timing errors that are audible that is entirely different from the typical jitter timing errors. It's a groundbreaking study since it created a new, valid way to measure audio gear distortions and the impact of cable and vibration treatments. They have done this in a way to produce a peer-reviewed paper. I think they are considering AES given the high level of interest. You simply don't know enough information to make your conclusion about the test being inconclusive.

A Y · Oct 8, 2009

Originally Posted by Artisan Fan

You simply don't know enough information to make your conclusion about the test being inconclusive.

Fair enough. Let me rephrase: the test as described in the link does not have enough information for it to be meaningful.

Since you know the people involved, the most interesting thing to find out from them is how they synchronize the analog output of the CD player with the original signal when they do the subtraction. Also, how do they convert the original signal (which are presumably bits on a CD) to analog so that they can do the subtraction?

--Andre

Artisan Fan · Oct 8, 2009

Originally Posted by A Y

Fair enough. Let me rephrase: the test as described in the link does not have enough information for it to be meaningful. Since you know the people involved, the most interesting thing to find out from them is how they synchronize the analog output of the CD player with the original signal when they do the subtraction. Also, how do they convert the original signal (which are presumably bits on a CD) to analog so that they can do the subtraction? --Andre
I don't know Steve and Roy real well but I will try to get you some answers. Some of my audio buddies are fairly close to them. I think you will find the test quite robust.

Artisan Fan · Oct 8, 2009

From Stereophile coverage of RMAF:

Cable manufacturers Nordost and Vertex AQ had good reason to present their joint seminar, "New Approach to Audio Measurement: Why Cables Really Matter," no less than five times during the show. As Art Dudley will report at length in his December "Listening" column, their groundbreaking new approach to measurement, developed by Nordost and Vertex AQ in collaboration with military electronic-engineering consultant Gareth Humphrey Jones, has produced an entirely new method for measuring the audible effects of components on sound. We're talking not only cables, support platforms, and the like, all of which can now be unequivocally shown to affect a system's sound quality, but also CD players, amplifiers, and speakers.

Co-presenters Roy Gregory of Nordost (former editor of HiFi+) and Steve Elford of Vertex AQ (pictured) projected a series of graphs that for the first time definitively demonstrated the effects of audiophile power cables, supports, and the Quantum device on sound. They also measured differences between CD players. Simply changing from a stock power cord to a well-made audiophile cord resulted in a 36% reduction in timing errors between the original WAV file and the same file burned on to a CD and played back by a typical high-quality player. Vertex AQ's support platform further reduced noise by 15%. The Quantum unit reduced noise by another 11%. Furthermore, there was no apparent hierarchy; if the support platform had been introduced first, rather than the power cord, its effect on errors would have been far greater.

Errors and effects that were formerly attributed to jitter have for the first time been identified as program-related using real music as the test signal. These errors cannot be identified by the standard continuous tone tests that everyone and their mother have been using all these years. To quote Roy Gregory, "We knew this stuff worked, but we didn't know why. Now we can gain insight into how to construct cables, CD players, and amps to produce better sound."

According to Gregory, the so-called law of diminishing returns, which says the more costly, high quality parts you put into a cable or device, the less of an improvement you will hear, need no longer apply. Using this new form of measurement to perfect products, it should now be possible to mate properly designed cables, components, and supports to deliver sound that reflects every bit of the time and investment devoted to their design and manufacture. This will not happen overnight—developing these measurements took a good six months, and this is very much a work in progress—but the results so far are extremely heartening. Bravos and gratitude to all.

Dmax · Oct 8, 2009

Originally Posted by Artisan Fan

Dmax, also read the link. It clearly shows the improvement of cables alone. In fact, they demonstrated the benefit of fine cables separately which is also how they conducted the tests.
The link in your post tells me nothing at all. It's just a tiny random graph where I'm not even sure what the 'X" axis is suppose to represent. I was going to make a list of things they did not bother mentioning in that "test" but I decided it easier to just list what they mentioned, which is the use of some of the devices they sell reduces some sort of errors in something. There is no mention on how the elimination of these errors, whatever they are, actually affects what a person hears. I find a great irony in the fact that these manufacturers claim to have "developed a new method to measure the previously unmeasurable". Maybe the reason that this perceived difference was unmeasurable is that it doesn't exist and no reputable double blind study has ever concluded that the participants can hear any difference whether $6,000 cables, $400 rubber feet or "Quantum Devices" whatever the f* that is, are used or not.

Artisan Fan · Oct 8, 2009

Originally Posted by Dmax

The link in your post tells me nothing at all. It's just a tiny random graph where I'm not even sure what the 'X" axis is suppose to represent. I was going to make a list of things they did not bother mentioning in that "test" but I decided it easier to just list what they mentioned, which is the use of some of the devices they sell reduces some sort of errors in something. There is no mention on how the elimination of these errors, whatever they are, actually affects what a person hears.

I find a great irony in the fact that these manufacturers claim to have "developed a new method to measure the previously unmeasurable". Maybe the reason that this perceived difference was unmeasurable is that it doesn't exist and no reputable double blind study has ever concluded that the participants can hear any difference whether $6,000 cables, $400 rubber feet or "Quantum Devices" whatever the f* that is, are used or not.

You are being too dismissive. They conducted the tests with one of the most respected sound engineers in the U.K. You and Andre just assume this guy would not be smart enough to build a proper protocol but there's no evidence in the links or articles to show that.

I sent an email to a good friend of these two and I should have more detail to share soon.

GQgeek · Oct 8, 2009

Originally Posted by Artisan Fan

You are being too dismissive. They conducted the tests with one of the most respected sound engineers in the U.K. You and Andre just assume this guy would not be smart enough to build a proper protocol but there's no evidence in the links or articles to show that.

I sent an email to a good friend of these two and I should have more detail to share soon.

Did you tell them you were having trouble proving their claims to you e-arch-nemesis?

A Y · Oct 9, 2009

Actually, it looks like Dmax's and my BS-meters are working pretty well. If you go to the Stereophile blog page quoted, and read the comments, you will come upon this comment left by Demian Martin (emphasis mine):

http://blog.stereophile.com/rmaf2009...o_measurement/

I sat through the presentation. I was struck by the lack of understanding by the presenters of the information presented and the reluctance to offer up any details. I thought the analysis of the data was very lacking and the conclusions presented (cables, noise filters, mechanical isolation make a big difference) were not supported by the by the data presented. This is a big mistake. If there is something in this the initial bad methodology will color the acceptance of it later. The interesting data was in the changes caused by the addition of an accessory, the rest was not particularly meaningful. I'm surprised that the spectrum (FFT of the time data) was not presented. Without the actual data to process its difficult to draw conclusions, especially the "missing link" conclusions presented. The lack of transparency and the vague response to questions about an AES paper or how the measurements were made has this more of a cold fusion story than a breakthrough room temperature superconductor

Demian Martin co-founded Spectral, one of the most respected brands amongst hard-core audiophiles, and engineered many components well-regarded by that same group.

And here is AF's opinion on Spectral:

Originally Posted by Artisan Fan

The Spectral gear is sublime.

--Andre

Artisan Fan · Oct 9, 2009

Originally Posted by A Y

Actually, it looks like Dmax's and my BS-meters are working pretty well. If you go to the Stereophile blog page quoted, and read the comments, you will come upon this comment left by Demian Martin (emphasis mine): http://blog.stereophile.com/rmaf2009...o_measurement/ Demian Martin co-founded Spectral, one of the most respected brands amongst hard-core audiophiles, and engineered many components well-regarded by that same group. And here is AF's opinion on Spectral: --Andre
Spectral gear is sublime but Keith Johnson's mainly responsible for that as the main designer. Demian's comments are bizarre for a number of reasons: 1. In the presentation, they explained 2-3X that this was a work in progress and that the research is still ongoing. 2. Joe Reynolds told me that they are planning a white paper and hope to get it in AES. 3. In the presentation there was a spectral graph. Not sure what Demian is referring to. 4. Steve Elford carried the bulk of the technical discussion with Roy Gregory translating into plain english for some journalists in the audience. Steve is clearly a talented, smart guy and knows the subject. 5. My opinion of spectral gear is not related to the discussion. And Andre criticizes my ability to put together a logical argument.

A Y · Oct 9, 2009

Originally Posted by Artisan Fan

Demian's comments are bizarre for a number of reasons:

I don't think so. Nothing you say contradicts his opinion that the data didn't show what they claimed it showed, and that the principals didn't understand what they were talking about. Let's look at each of your points:

1. In the presentation, they explained 2-3X that this was a work in progress and that the research is still ongoing.

That's fine, but it's no reason to misinterpret or not understand what your data's telling you, nor obscure it. If someone in the audience who's seen your data for less than an hour can start poking holes in your hypothesis, that's not a result of unfinished work, but rather bad thinking and analysis.

2. Joe Reynolds told me that they are planning a white paper and hope to get it in AES.

Fine, but that's full of weasel words: "planning" and "hope". It doesn't contradict what was said by Demian ("vague response about an AES paper"). In fact, in another comment, Kal Rubinson, who knows a thing or two about the scientific review process, debunks their claims of peer review through submission to MIT. That's an appeal to authority and a classic BS warning sign.

3. In the presentation there was a spectral graph. Not sure what Demian is referring to.

That's good. What was it a spectrum of, and what did it tell you about their measurement?

4. Steve Elford carried the bulk of the technical discussion with Roy Gregory translating into plain english for some journalists in the audience. Steve is clearly a talented, smart guy and knows the subject.

Demian, who's not an untechnical person, doesn't seem to think so. So it's your word against his. We'll call this one a push.

5. My opinion of spectral gear is not related to the discussion. And Andre criticizes my ability to put together a logical argument.

Try again. Spectral is not well-known outside of audio circles, and I used you as an example of how fundamentalist audiophiles respect that company, so the peanut gallery would know the significance of that comment.

--Andre

Artisan Fan · Oct 9, 2009

I don't understand the point on Spectral. You are saying that audiophiles respect the company so it is suspect? So you are discrediting your own source above?

A Y · Oct 9, 2009

Originally Posted by Artisan Fan

I don't understand the point on Spectral. You are saying that audiophiles respect the company so it is suspect? So you are discrediting your own source above?

Demian Martin is well-known and respected by a wide cross-section of the audio community. What he says does not come from a position that is partisan to any one group of the community. The styrofoam-and-cables crowd respect him as much as the objectivist crowd does, and so his comment is significant because he doesn't have an axe to grind.

If Tom Nousaine or Peter Aczel had said the same thing, their comments would have been suspect (even by me) because they've demonstrated irrational hostility and close-mindedness towards the subjectivists. Martin straddles both sides, and has considerably more credibility because of that.

--Andre

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