In article , Richard Young
wrote:

Hello all,

Just joined here, having found the site while searching for information
relating to a presentation today at the National Audio Show about the
Vertex AQ/Nordost/Quantum 'Measurement Initiative'. So I thought I'd
post what I found to this thread....

The results shown look like nothing more than those one would expect due
to time-slip between the device-under-test output and the sampling
instant of the test instrument. I mean there's very little difference
between them when the signal is nearly flat, and a lot when it changes
rapidly. The phasing between signal and sampler is absolutely critical,
but has zero effect in the real world of course, which is the biggest
reason why this kind of test is usually avoided.

I would help if you explained what exactly was being 'measured', how this
was being done, and what items were being subjected to the measurement and
giving the results you describe. Sounds just like a version of the ancient
Hafler difference approach which does usually give the predictable results
- i.e. that most audio gear works fine - once you have cancelled obvious
factors like frequency response tailoring.

The 'Defence contractor' Advansys is a tiny outfit (turnover around
£100,000 according to latest Companies House accounts) and a look at its
website ('Advansys Solutions - The New Contact in Sonar'
(http://www.advansyssolutions.co.uk/)) suggests it doesn't actually work
much on the signal-processing side of sonar anyway. Its 'audio
subsidiary', Acuity Products Ltd, was set up in December last year and
hasn't filed any accounts yet.

I have a vague feeling I've heard of this before. But can't say more unless
you or someone else actually explains *what* results on *which* equipment
you are talking about.

Only got into this because on the way home up the M6, I bet my mate a
tenner that the claims would turn out to show nothing new - so far I
look like winning, I guess!

Easy bet to win. :-)

Slainte,

Jim

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