Purité Audio
Trade: Purite Audio
How would he conduct a phase coherence demonstration?
Keith.
Keith.
Microphony III
- Thread starter BE718
- Start date
Steven Toy
Accuphase newbie
Perhaps you should go and find out, Keith. You might learn something!
Purité Audio
Trade: Purite Audio
I really would like to know, how were these demonstrations conducted?
Keith.
Keith.
Steven Toy
Accuphase newbie
As I said, you should perhaps visit them and find out. It is not for me or anyone else to step into Larry or Ed's shoes on pfm.
Paul Mc
pfm Member
This thread like so many has turned into an attack on a hifi dealer who has been called all the names under the sun. Why Tony allows this to happen is beyond me, and while he is all too happy cut out posts from me about the double standards at play on this thread he seems more than happy to stick the boot it too.
It is seens acceptsble to suggest we are all - inclduing most senior hifi reviewers - imaging differences, aceeptable to use one experiment, without peer review, or replication, to dismiss what I believe is a wokring hypothesis to explain why these devices improve the sound of hifi equipment. it is however acceptable for a small number of loud mouthed bullies to crash into every thread accusing well established dealers of tricking people out of their money. Time to stop it.
It is seens acceptsble to suggest we are all - inclduing most senior hifi reviewers - imaging differences, aceeptable to use one experiment, without peer review, or replication, to dismiss what I believe is a wokring hypothesis to explain why these devices improve the sound of hifi equipment. it is however acceptable for a small number of loud mouthed bullies to crash into every thread accusing well established dealers of tricking people out of their money. Time to stop it.
Steven Toy
Accuphase newbie
One of the worst offenders seems to be another dealer which I find odd as this can hardly be good for his business.
It was a number of years ago. ISTR they were selling off Naim ex dem stuff because they had recently stopped selling it if that helps with dates. A friend of mine had a standard 80s student system of Rotel amp, AR speakers some record player and Technics CD that was falling to bits. We lived in Macclesfield at the time so toddled off to Cheadle to see what was what in hi fi these (those) days. We started with a Sugden CD player, amp and (I think) Neat or Rega speakers. We went through a series of upgrades and ended up listening to a Focal/Accuphase system wired up with MIT cables. Phase coherence wasn't demonstrated as such but it was the story, the magic ingredient if you will, which made the difference the higher you went up the ladder.
What else are you looking for from BE718?
He has measured how much vibration is in the case (not the circuit boards or components due to the mass of his accelerometers) of his DACs and amp, excited in a few different ways, and measured the results using equipment that he uses at work. He has meaured vibration levels in the stand and shown how low they are and how stand to equipment interaction is most likely to be working. The measurement equipment could be faulty but presumably that would be found out when using it at work and the kit is calibrated.
Yes it is the only body of published work that I have seen and I would like to see more data like this published. Along with other ideas as to how these stands might work being assessed (do they actually work and what mechanisms are there for how could they work).
Maybe tellingly the stand manufacturers do not publish such data, perhaps because they have not measured anything like this or perhaps their results agree so it would not help them sell their stands.
Steven Toy
Accuphase newbie
To be fair BE718 has not denied the efficacy of the product. He has simply thrown up some doubt as to the causing mechanism.
To be fair on this (if you havent already realised) although I havent outright denied the efficacy of the products to make any discernible change to the sound, I am highly sceptical.
Vibration is the only mechanism I can personally think of, and we have demonstrated that there is little vibration to start with and the support surface doesnt stop the equipment vibrating of its own accord anyway.
If anybody has any suggestions as to other mechanisms, please shout.
Perhaps someone could approach some stand manufacturers and see if they are willing to share some of the vibration test data they have for their products?
I am fairly confident the answer will be a resounding no.
Hi Bill,
I am happy to do some more testing/video as I get time. Happy for suggestions for things to try.
Yes you are correct the Exp averaging does take some considerable time to finally settle. I set 100 averages (plus the long time a high res FFT takes per measurement), nothing further seemed to change by increasing further.
I know the video was quite limited in what it shows, but I have played with many different permutations and I really cant provoke any reaction at these acoustic levels.
BTW I used to work at Rolls Royce aero engines, mainly military, in test measurement.
Paul,
It is perfectly acceptable to suggest that there are many mechanisms which affect individuals perceptions. You shouldnt automatically take that as someone is "imagining". Nonetheless, like it or not, even that is a possibility.
Individuals are also entitled to voice their opinions.
Its not time to stop it at all. If your view is that these items do what they say and isolate vibration and stop equipment from vibrating (the proposed causal mechanism) then please feel free to provide some evidence that they do. However what we have measured so far, with calibrated professional equipment indicates that they dont.
It seems to me that there are some individuals who just dont want to hear these answers.
Werner
pfm Member
Surely you are aware of the Nordost / Vertex AQ / Acuity measurement initiative of five years ago which in an unprecedented flash of genius proved for once and for all that cables and anti-vibe products actually do work? Validated by the MOD, the word spread eagerly by one Roy Gregory ...
http://www.nordost.com/downloads/NewApproachesToAudioMeasurement.pdf
https://www.youtube.com/watch?v=MSAd2ntP4FM
http://www.hydrogenaud.io/forums/index.php?showtopic=75130
This story was an absolute gem, something to treasure. Even better than the Kunchur Kase.
But if you look at the perpetrators' own website on this subject you get
http://www.vertexaq.com/content/view/36/1/
Paul Mc
pfm Member
As I stated earlier, I do know, and as do many on this site, what you plonk your hifi on makes a difference. Why that is I don't know. I do know that one experiment does is not proof. But this is not the issue for me. I strongly object to the targeting of one dealer, by a cabal who are using your work to make all kind of accusations. That is what should stop. Measure to your heart's content.
Musicworks Hi-fi sell the Revo 3 equipment rack than Steven believes isolates his system from vibration for £1500. Musicworks claim that this stand achieves "the highest degree of equipment isolation". Steven, can you ask Musicworks what their response is to BE718s measurements? Can you ask them to produce their own measurements, which they surely must have in order to make the claims they do?
Steven Toy
Accuphase newbie
As it happens, I'm off there later today. My Rega Apollo R is a little flaky and needs some TLC before the warranty runs out later this month. I'll ask but I shall try avoid asking rhetorical questions as this would make me sound like a ...
You have deliberately misrepresented my position, btw.
Thats all pretty funny, where do you start with the flaws in the test?