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In the Forum: Audio Discussions
In the Thread: Measuring reality: empirical mode decomposition
Post Subject: The contemporary speaker building techniquesPosted by Romy the Cat on: 3/3/2008

 decoud wrote:
It seems there is broad agreement here with what I take to be Romy's position, which is that one cannot have a sophisticated understanding of music reproduction if one does not have a sophisticated knowledge of music.

It never was my position, sorry. I never stressed any “knowledge of music”, not a lot of the reason is that I do not have this knowledge. So, what you said is your perception not my expression.

 decoud wrote:
Now all of this would be easier if one had some better measures by which the fidelity of reproduction could be gauged - not as a substitute for listening but as an adjunct. The various functions of frequency commonly quoted are not very useful because they assume that the sound is stationary, which of course it is not. The only non-stationary test one tends to see - the response to a step function - is of course a very artifical thing.

So, what we need is a method for analysing non-stationary, non-linear, time-varying signals. The best of these is probably empirical mode decomposition.  Romy, would you be persuaded to give it a try? (there is a version for MATLAB here http://perso.ens-lyon.fr/patrick.flandrin/emd.html) I do not for a minute believe it would be as good as a human ear, but it may be interesting to show that it can capture aspects of "reality" missed by crude things such as bandwidth and distortion values.

Sounds interesting or at least entertaining. I have no personal experience with EMD, and even if I had I doubt that I have expertise to enterprise the result into some kind of useful conclusions. I generally do not use any of the contemporary speakers design and evaluation techniques. All those TEF analyses and maximum length sequence system analyses are good but I do not do it. It is not that I am against any time-domain metrics but I never had needed it and my thinking about sound does not incorporate any time-domain analyses. You probably found someone more intelligent on the subject even to support this conversation…

Do not forget, decoud, that no of the methods of mathematic approximation of realty measure the actual Reality. The time-domain metrics, the decomposition method and anything else measure juts reflection of Reality in term of language of Reality description, nothing more. It is a powerful tool… for those who need it. However, the adoption of this language to describe Reality has some intrinsic problems in my view a person do not deal with Realty anymore but with semi-scientific surrogate of Reality.

Rgs, Romy the caT

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