Hmmm..... they may have set this up since RMAF2009. This isn't the company I remember. Vertex and Nordost contracting them to make the measurements must have been lucrative!
Objective measurements for power cables???
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Hmmm..... they may have set this up since RMAF2009. This isn't the company I remember. Vertex and Nordost contracting them to make the measurements must have been lucrative!
Possibly because the original data was a CD at 44.1kHz and they wanted to compare the output without any interpolation of either the input data or the output data?
I don't think that it was as a favor to Nordost. Their partner in this measuring venture, Vertex, is owned by Steve Elford. Steve produced hifi stuff (cables, power conditioners and racks) as a sideline, and his main business of military contracting finances his "hobby". They were (and still are) a competitor to Nordost. Steve brought some of this finding to Roy Gregory who was the Editor of the UK-based magazine HIFI+ at that time. Roy thought that it was extremely interesting, and when he left HIFI+ and joined Nordost, he convinced Joe Reynolds to finance more investigation.
I know that this smacks of cable company b.s. but when I met the three of them last year, they genuinely thought that they had found a new form of measurement that would advance the science of audio reproduction. They are financing the investigation into cables and power conditioning, but there is no reason why an amplifier company can't pay Acuity Products to measure amplifiers the same way.
The results make it sound simple, but if you've tried recording the output of a CD player and comparing it to the CD itself using Audio Diffmaker you will find that it is a non-trivial task. The biggest problem is synchronizing the sampling to the input - otherwise you are sampling at a different place in the waveform and the comparison is totally invalid.
I know that this smacks of cable company b.s. but when I met the three of them last year, they genuinely thought that they had found a new form of measurement that would advance the science of audio reproduction. They are financing the investigation into cables and power conditioning, but there is no reason why an amplifier company can't pay Acuity Products to measure amplifiers the same way.
The results make it sound simple, but if you've tried recording the output of a CD player and comparing it to the CD itself using Audio Diffmaker you will find that it is a non-trivial task. The biggest problem is synchronizing the sampling to the input - otherwise you are sampling at a different place in the waveform and the comparison is totally invalid.
This is why the sampling rate has to be 44.1 for both input and output.
Here's the waveform of a piece of music I have at 24/192 -
View attachment 1222
I downsampled it to 44.1kHz (as it would have to be in order to make a redbook CD). Then, up-sampled it again to 24/192 so that I can use Diffmaker to extract the difference and here is the result:
View attachment 1224
Zooming in to 20% like what the study did to present the differences.
View attachment 1223
The act of upsampling/downsampling would invalidate the result.
By the way, the SRC used was SoX linear phase.
Here's the waveform of a piece of music I have at 24/192 -
View attachment 1222
I downsampled it to 44.1kHz (as it would have to be in order to make a redbook CD). Then, up-sampled it again to 24/192 so that I can use Diffmaker to extract the difference and here is the result:
View attachment 1224
Zooming in to 20% like what the study did to present the differences.
View attachment 1223
The act of upsampling/downsampling would invalidate the result.
By the way, the SRC used was SoX linear phase.
Did I say I love the Internet? I thought I did
http://www.nordost.com/downloads/New Approaches To Audio Measurement.pdf"The test rig consisted of the CD player, sat on the top shelf of the
Quadraspire rack and power using a standard IEC AC cord. A bit perfect
copy of a particularly energetic musical passage (on the basis that it’s
exactly this sort of signal that causes hi-? systems most problems) was
made on a PC and then the disc was replayed on the CD player, the
same passage fed from the analogue outputs of the player, back into
the PC, via a high quality sound card, where it could be compared to
the original data."
As I noted, they would be better off dispensing with the nonsense of sonar, military science, math, etc. This is a simple process of redigitizing the data using the sound card. My original objection remains that there is no control with regards to the capture device. We don't know if the capture PC's analog noise spectrum changed due to unknown factors.
BTW, i don't see them changing contractors. I think the same guy was used at the start. Here is his bio: http://uk.linkedin.com/pub/gareth-humphreys-jones/4/186/150
Dang, Amir. Your investigative skills are noteworthy. Hey, I am in need of a new P.I. My P.I. retired after several years in private practice, preceded by working for many, many years for the Alameda County D.A.'s office. Next time I need an investigation, I'm calling you!
. I like to say that any question man has, has an answer somewhere on the Internet. It is just the matter of knowing how to find it.I think the biggest issue at hand is whether we believe the test at all. They made many claims that are not true. They said some military company was behind this. It appears to be a one-man show doing consulting. They implied sophisticated measurement techniques were used. Now we know it was an unknown sound card on a PC. No detail is provided as far as sample matching, the hardware used for capture, etc.
So where I stand right now is that I like to see the test repeated. Until then, I no longer assume what they have done is Kosher. I think they did such a great job of making it sound like this was a huge undertaking that no one else thought to ask for the results to be duplicated. Recall how they said they could not make the same measurements. Really? They lack a PC with a sound card?
I like to try to duplicate their results but hate to have to buy their cables to get there
.
Seems to me that the test, and the people conducting it have been invalidated. I'm not sure I'm at all interested in seeing it repeated.
Tim
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