Complex signal analysis
 

An interesting new approach to signal analysis is (sketchily) described
on the following pages, it appears to be an attempt to apply FFT
techniques to analysis of music signals.

http://www.quantumqrt.com/submenu.as...3&ContentID=24

http://www.vertexaq.com/content/view/36/1/

Too complex for my hamster brain to grasp.
Any comments?
--
Ken O'Meara.
http://unsteadyken.110mb.com/

Complex signal analysis
 

On Sun, 9 Aug 2009 23:35:03 +0100, UnsteadyKen
wrote:


An interesting new approach to signal analysis is (sketchily) described
on the following pages, it appears to be an attempt to apply FFT
techniques to analysis of music signals.

http://www.quantumqrt.com/submenu.as...3&ContentID=24

http://www.vertexaq.com/content/view/36/1/

Too complex for my hamster brain to grasp.
Any comments?

Yes, but I'm far too polite to print them here. Spend money on this
and you get exactly what you deserve.

d

Complex signal analysis
 

"UnsteadyKen" wrote in message
m
An interesting new approach to signal analysis is
(sketchily) described on the following pages, it appears
to be an attempt to apply FFT techniques to analysis of
music signals.

http://www.quantumqrt.com/submenu.as...3&ContentID=24

Seems to be based on signal subtraction which unfortunately conflates a
number of differt kinds of distortion and in general makes equipment signal
accuracy seem far poorer than it actually is.

For an example, I can take an audio signal and apply some phase shift, and
drastically change its maximum amplitude and also create a large difference
between the input and output. Without knowing a priori how the signal was
changes, what does this apparenly large difference tell me?

Far more to the point would be to calaculate the transfer function of the
device by use of the FFT.

http://www.vertexaq.com/content/view/36/1/

More of the usual signal subtraction BS.

Any comments?

Strictly bush-league stuff.

Complex signal analysis
 

Don Pearce said...


Yes, but I'm far too polite to print them here. Spend money on this
and you get exactly what you deserve.

I was curious as to whether it was a valid new testing technique which
had wider applications or whether it was just designed to show the
products in a good light. It seemed a trifle mysterious as the
developers:"Acuity, the audio division of Avansys Systems" neither of
which companies show up with a quick 'Google'

--
Ken O'Meara.
http://unsteadyken.110mb.com/

Complex signal analysis
 

Arny Krueger said...

Strictly bush-league stuff.

Oh well, not a giant leap for science then.

--
Ken O'Meara.
http://unsteadyken.110mb.com/

Complex signal analysis
 

On Mon, 10 Aug 2009 02:44:32 +0100, UnsteadyKen
wrote:

Don Pearce said...


Yes, but I'm far too polite to print them here. Spend money on this
and you get exactly what you deserve.

I was curious as to whether it was a valid new testing technique which
had wider applications or whether it was just designed to show the
products in a good light. It seemed a trifle mysterious as the
developers:"Acuity, the audio division of Avansys Systems" neither of
which companies show up with a quick 'Google'

No, as a an analysis method it really doesn't work. The sheer size of
the errors it purports to reveal is evidence enough of that.

d

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.

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) 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.

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!

Complex signal analysis
 

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

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Complex signal analysis
 

"UnsteadyKen" wrote in message
m
An interesting new approach to signal analysis is
(sketchily) described on the following pages, it appears
to be an attempt to apply FFT techniques to analysis of
music signals.

http://www.quantumqrt.com/submenu.as...3&ContentID=24

http://www.vertexaq.com/content/view/36/1/

Too complex for my hamster brain to grasp.
Any comments?

Lotsa smoke, no visible fire.