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Old 7th February 2011, 05:26 PM   #9621
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Quote:
Originally Posted by 1audio View Post
Sounds a lot like you want to build one of these: Danbridge
I have two of the earlier version and have looked at a lot of components with them. Carbon comp and carbon film do show higher nonlinearity than metal film, foil and wirewound. No magic there. There is even some stuff in the literature describing why.

Its very difficult to build one of these and make sure its actually working right. The cap analyzer (details forgotton already) is similar but doesn't have the low Z drive combined with the high Z load at the harmonics. However he does show how to make something close.

The noise index gives pretty similar information in practice. Bad distortion tends to correlate with high noise (except where there is magnetic materials).
The references I have read using the CLT mentioned third harmonic not a dead zone (all odds well beyond third). This is well known and not a surprise.
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Old 7th February 2011, 06:33 PM   #9622
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On its own? I.e., not while playing an LP?

se
No, with the record playing.
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Old 7th February 2011, 06:38 PM   #9623
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ED, here's an article on building your own CLT with comparisons to the real thing.

http://downloads.hindawi.com/journal...978/473873.pdf
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Old 7th February 2011, 06:43 PM   #9624
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One of our Professors at the University ....
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Old 7th February 2011, 07:02 PM   #9625
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Quote:
Originally Posted by scott wurcer View Post
ED, here's an article on building your own CLT with comparisons to the real thing.

http://downloads.hindawi.com/journal...978/473873.pdf
Interesting, very close to my 10 resistor method, the limit in the paper is the one reference resistor. Their method is also dependent on the quality of the drive oscillator.

What is more interesting is that they only look at the third harmonic but recognize more are there.

What is interesting is this quote from Danbridge

"Some components contain materials which inherently have a high distortion:
Magnetic materials, composition resistors, high-dielectric capacitors etc. In
these components, the excessive distortion from a small defect is hidden in
the high inherent distortion and cannot readily be detected.
At the other end of the scale, we have metal-film resistors where the inherent
distortion is very low, typically -130 dB or lower, and the wire-wound types
which normally exhibit even lower distortion. With these components, defects
give rise to a distortion which normally exceeds that of the rest of the batch."

But I just got in a package with no return address and assembly instructions for a "interocitor." I think I'll take a break and try to put it together.
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Old 7th February 2011, 07:39 PM   #9626
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Originally Posted by simon7000 View Post
John,

Linear or non-linear here we can disagree. Most of my experience is with acoustic resonances which in start up mode is non linear.
There is no disagreement on such a simple thing.. Linear is linear, non linear is non linear. Acoustic resonance is not by nature non linear. It is only when the moving or absorbing entities move sufficiently to enter a non linear region that non linearities apply. One example would be a tuning fork where the tines are sticking through tight toleranced holes such that excessive movement causes impact. Or a compliant material which becomes rapidly non linear as a result of compressive stress or acts non-newtonion.

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Seems we are getting into chaos theory.
No we are not getting into chaos theory. Besides, what do production meetings have to do with audio???

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But I think we all agree movement in a vacuum tube either externally applied or from internal forces can be an issue. As tube design progressed they certainly made the internal parts stiffer.
Never said otherwise..total agreement.

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Originally Posted by simon7000 View Post
I mentioned my example of a church where adding 16 sabins of absorption changed it from bad to good for speech. I understand most folks reading that would not understand why that is so amazing. As the church was 500,000 cubic feet or so and already would have had 3000 sabins of absorption it is almost mind boggling that adding 16 more at the right place would solve a resonance (Not a slap back.) If the start of resonance were linear that would not have happened.
It most certainly would... Look at your words I hilighted...that is the key. Putting 10,000 sabins in null locations does nothing.. It's the nodes where absorbtion is most efffective.

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Buckling behavior as I used it is a motion off axis to the applied force caused by non-uniform strength of the column. An argument over semantics I think we can leave to others.
The term buckling implies non-linearity. What you are speaking of is not buckling, but a 3 dimensional response to a 3 dimensional problem of stiffness, mass and excitation. Buckling in the materials world is the plastic deformation of a material as a result of exceeding the strength of the material.. You unfortunately used a word which while seemingly descriptive, invokes something else altogether...

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Any order of the model past first is just way over my head!
Me too.. Not only is it not first order, it's not even second..three axis of mass, three of stiffness, three of force....easier to measure..

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Originally Posted by simon7000 View Post
As to the picture it started out as two AL boxes, I tried the steel overcoat to see if there would be any change, there was not. All the magic really occurs in the small cast box. This example was made out of my junk box. I consider the proof of concept to be far enough along I may build a specific gizmo to look deeper.
Cool. Good luck.

Cheers, John

ps..Other than the vaccine guy, I've never heard of sabin. You use it as if it is a measure of absorbtion units.. I assume you know what you are talking of here..so I use the term above as if I actually knew what it was.. I did find Sabin 3.0 - Statistical Acoustics Based Investigator... Is that what you were referring to?? Or did you actually dangle guys named Sabin around the room?

Last edited by jneutron; 7th February 2011 at 07:46 PM.
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Old 7th February 2011, 07:58 PM   #9627
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Originally Posted by jneutron View Post
[snip]ps..Other than the vaccine guy, I've never heard of sabin. You use it as if it is a measure of absorbtion units.. I assume you know what you are talking of here..so I use the term above as if I actually knew what it was.. I did find Sabin 3.0 - Statistical Acoustics Based Investigator... Is that what you were referring to?? Or did you actually dangle guys named Sabin around the room?
He probably means the Sabine reverb equation?

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Old 7th February 2011, 08:04 PM   #9628
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Now, for the price of phono cartridges. In the beginning, let us say 1974, the $100 figure was close to the mark. Well, what happened?
Well, one cartridge importer decided to raise the prices, and get away with it by having a nice presentation box and packaging. So the new, improved models got more and more expensive, by 1988, perhaps $500 for a mid-line MC phono cartridge. Yes, you could pay, even then, much, much more. Ortofon got into it and just about outdid everybody in packaging. Wow! But what about the sound? There were incremental improvements, but there was a lot of 'fat' in there that was just excess profit. Who made the money? The manufacturer's? NO, the importers, who often sold a phono cartridge under their own name. They would just pick them out of a sample box and then design a distinctive cartridge shell. Some people, who were poorer than me, when I first met them, became millionaires by this process. And so it goes.
Now, what about today? Is it still the same? Somewhat different? Yes, to both.(more later)
I'm not sure that all the expansive phono cartridges are only repacked cheap ones.
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Old 7th February 2011, 08:23 PM   #9629
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John:

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Guess what, there is something else about the guitars that I like, it is called 'sound quality' and that is difficult to measure. I certainly don't know how to, anyone have any suggestions? (more later)
This guy has done it for violins. You might find it interesting.

Master Studio for Violinmaking - Martin Schleske Munich, Germany Sound Analysis
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Old 7th February 2011, 08:30 PM   #9630
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And here for the Stradivarius.

A stradivarius is definitely different - News 2010 - News & Events.

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