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Some Scientific Data on Isolation, Power, and Cables

post #1 of 97
2/8/10 at 1:43pm
Thread Starter 
Nordost engaged a team of UK defense contractors with deep radar/communication experience named Acuity Products along with power supply and isolation maker Vertex AQ to create a scientific basis for audio gear isolation, power improvements and better cable. What separates this study is the use of high quality test gear and an interesting look at sound quality by looking at changes in distortion during replay under various conditions which are essentially these audio tweaks being applied.

Acuity has recently published some results that I thought many here would find interesting:

http://www.acuityproducts.co.uk/Case...-%20Vertex.pdf

Quote:
In the interest of clarity, Figures 4 – 6 have been expanded to display +/- 20% amplitudes and, to put these Figures in context, if the replay from the CD player was a perfect replication of the test track, and introduced no distortion, then the difference graph would be a straight
line at zero amplitude. Thus, the deviation away from such a horizontal line represents the distortion introduced by the replay mechanism.
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post #2 of 97
2/8/10 at 1:44pm
Thread Starter 
Also, this test looks at the impact of a Quantum QX4 power box:

http://www.acuityproducts.co.uk/Case...%20Quantum.pdf
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post #3 of 97
2/8/10 at 1:54pm
Thread Starter 
Further reading...click on the next button below to see the graphs:

Quantum Resonant Technology
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post #4 of 97
2/8/10 at 2:02pm
They changed three variables for the third graph, I am appalled, that is an amateurish error of the grossest kind, my supervisor would have had me flayed alive if I presented data as badly controlled as that !

Oh and the samples do not look perfectly time aligned, which makes the results very iffy, and there is no scale , no units and no description of what kind of distortion they are measuring, what are they calling distortion and how exactly did they measure it ?. It looks like a simple FR difference, if so I am a bit skeptical about their figures 10% distortion is an absurd level for any digital component and about 4 orders of magnitude worse than what you would expect.

What did they measure, what did they use (software) to do so, did they take digital or analog outputs, and so on...how big was the sample. How many times did they repeat the sampling for each configuration, not once surely.

I would really like to see the raw data.
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post #5 of 97
2/8/10 at 2:07pm
Thread Starter 
Quote:
Originally Posted by nick_charles View Post
They changed three variables for the third graph, I am appalled, that is an amateurish error of the grossest kind, my supervisor would have had me flayed alive if I presented data as badly controlled as that !

Oh and the samples are not correctly time aligned, which makes the results very iffy, and there is no scale , no units and no description of what kind of distortion they are measuring, what are they calling distortion ?

What did they measure, what did they use (software) to do so, did they take digital or analog outputs, and so on...how big was the sample. Howe many times did they repeat the sampling for each configuration, not once surely.

If acuity would like to send me their raw data I will happily analyze it properly for them.
The samples are time aligned. They discussed this in detail at RMAF. These guys are applied math whizzes with deep signal to noise experience who build radar gear for the RAF.
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post #6 of 97
2/8/10 at 2:10pm
Quote:
Originally Posted by nick_charles View Post
If acuity would like to send me their raw data I will happily analyze it properly for them.
That would make my day
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post #7 of 97
2/8/10 at 2:11pm
Thread Starter 
Quote:
Originally Posted by El_Doug View Post
That would make my day
Why would Nick have any special expertise in analyzing sound data over SNR experts?

Where is the evidence that Garreth-Jones improperly analyzed the data?
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post #8 of 97
2/8/10 at 2:13pm
Quote:
Originally Posted by TwoTrack View Post
Why would Nick have any special expertise in analyzing sound data over SNR experts?

Where is the evidence that Garreth-Jones improperly analyzed the data?
Because he would at least put units on the damned graphs?


Also... why is it that the solution to half of the crises in Star Trek: Voyager was "Quantum"?
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post #9 of 97
2/8/10 at 2:26pm
Why are you so certain that these "experts" are credible at all? Reading this report is leading me to believe that this "Acuity Products Limited" company is nothing short of a ploy to draw some sort of credibility to these cable companies. Why would they mention the cost of the CD player and then say it "measures excellent using conventional methods"? What conventional methods? No citations? Garbage.

Fraud if you ask me.


Edit: Wow, this article is a joke. If you honestly buy into this, then you are clearly naive.
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post #10 of 97
2/8/10 at 2:28pm
Well, I for one am curious to see what they come up with.

I don't really understand why you'd need to define the type of distortion in this case. That's not really the point.

Oh well, I might be wrong.

Edit: Isn't calling it 'fraud' a bit premature?
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post #11 of 97
2/8/10 at 2:36pm
Read their "extensive" 4 page document. There is nothing of merit in it whatsoever.

Now here is the kicker:

Acuity has done two tests. One on this Vertex cable and the other on some Quantum thing...

Check Figure 5 on the Vertex document and Figure 4 on the Quantum document.

You'll notice they are the SAME PLOT with a different amplitude scaling.

In fact, most of their plots are the same with different amplitude scaling.
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post #12 of 97
2/8/10 at 3:18pm
Quote:
Originally Posted by colonelkernel8 View Post
You'll notice they are the SAME PLOT with a different amplitude scaling.

In fact, most of their plots are the same with different amplitude scaling.
wow... they didnt even try to bullsh1t :/
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post #13 of 97
2/8/10 at 3:53pm
Shoddy work in my opinion. I thoroughly agree with Nicks summary. Presenting data in such a poor fashion reeks of incompetence.
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post #14 of 97
2/8/10 at 4:47pm
Quote:
Originally Posted by Slash47 View Post
Edit: Isn't calling it 'fraud' a bit premature?
Agreed, I don't see fraud I see experts in one field being careless and denying us enough information to draw our own conclusions.

The graphs are very difficult to read, the time slice used is 0.043 seconds, it appears to be a single shot analysis on each config so no allowance for normal random variation at all, cripes when I did my really crude cable tests I took 10 samples for each and averaged them, and I did not get paid for that.

In any case if this were an academic paper the methods section would come in for some criticism. Scaling up Figs 4,5, and 6 is sort of acceptable but only if they took segments where the differences were greatest and showed say Fig 1 and Fig 3 segs side by side with the expanded difference segment for these 15 - 18% difference slots. When you just eyeball the graphs these big differences seem implausible, that's why you really need the raw data.
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post #15 of 97
2/8/10 at 5:13pm
Thread Starter 
Quote:
Originally Posted by colonelkernel8 View Post
Read their "extensive" 4 page document. There is nothing of merit in it whatsoever.

Now here is the kicker:

Acuity has done two tests. One on this Vertex cable and the other on some Quantum thing...

Check Figure 5 on the Vertex document and Figure 4 on the Quantum document.

You'll notice they are the SAME PLOT with a different amplitude scaling.

In fact, most of their plots are the same with different amplitude scaling.
I think folks here need to be more open-minded; scaling is changed to make it easier to see. There is no fraud here. One of the graphs for instance charts the difference from the effect. It's not subtle.
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