Demian
For such a test that is influenced by the speaker/room interaction, I would expect that there would be an agreed upon standard for the crucial parameters: room, speaker placement, mic position, mic type. These, uniquely set for speakers with the same directivity pattern (omnis, OB, closed ect). Then, only speakers with the same directivity pattern could be tested against each other.
Otherwise there is no reason to do this.
OTH this test is valid for recording/play back equipment (reel tape, cassette, CD recorders)
George
That's a good question, and I will happily answer.
I was doing a research and design on DC - xMHz measuring amplifiers for measurements during short-circuit tests of HV SF6 circuit breakers. Measurements of current and arc and transient recovery voltage in the vicinity of current zero, like 10 - 20 us overall time interval within 100ms test. That means, measurement of about 20A portion of the 40 - 63kA 50Hz current wave. Yes, huge electromagnetic distortion, nothing that audio designer would ever have imagined. The measuring amplifier, that was directly connected with coaxial or squirrel cage shunt of 0.001 ohm resistance was asked to recover instantly from huge overload and then to measure precisely a portion of the current (after turn-off) less than 80dB below nominal value. So called post-arc currents, like 1-2A, 0 - 4us duration, from 63kA/50Hz. Any more questions?
P.S.: I cannnot provide you with citations from < 1989, but some similar ones from later period yes:
http://ieeexplore.ieee.org/xpl/logi...ore.ieee.org/xpls/abs_all.jsp?arnumber=854732
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maybe he was dumbing it down while speaking with an engineer
what a piker, still using that old fluid mechanics inspired jumble?
and the Gibbs Vector Algebra cockup with "independent" time? - a century after Minkowski?
a real physicist would start with Coulomb's Law, and just do the math right with Special Relativity, space-time 4-vectors
what a piker, still using that old fluid mechanics inspired jumble?
and the Gibbs Vector Algebra cockup with "independent" time? - a century after Minkowski?
a real physicist would start with Coulomb's Law, and just do the math right with Special Relativity, space-time 4-vectors
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JN,
Some people have absolutely no humility. They can never admit that someone else has something to offer or could know more than they do. I appreciate the help you offer and wish it was easier to keep all of your posts in one place for reference. I know I have asked you questions in confidence and you have gladly answered them. Thank you for being one of the people to bring sanity checks here to this forum and others where you may comment. It is always obvious when you are just playing, but when you give a real answer to a question it is both thorough and comprehensive. Those who have helped me know who you are and I appreciate all of you who do this and expect nothing but thanks in return.
Some people have absolutely no humility. They can never admit that someone else has something to offer or could know more than they do. I appreciate the help you offer and wish it was easier to keep all of your posts in one place for reference. I know I have asked you questions in confidence and you have gladly answered them. Thank you for being one of the people to bring sanity checks here to this forum and others where you may comment. It is always obvious when you are just playing, but when you give a real answer to a question it is both thorough and comprehensive. Those who have helped me know who you are and I appreciate all of you who do this and expect nothing but thanks in return.
It's not a question of knowing everything from first principles. It's a question of understanding the material.
Not a question of how big is my pile of books. It's all about comprehension of what's IN the books.
Finding some obscure effect in a book, then attributing some "non reproduceable" audible (trust me) effect to that obscure thing, is not comprehension.
It's marketing.
jn
I've used input/sampling bridges to do that. I remember seeing that kind of problem before, and was totally impressed with whoever figured out that method, both for input sampling, and as very fast overload protection.
I'm working on that solution for a junction temperature measurement circuit, so I can get the reading to settle down in roughly 10 uSec. I'll push 1 ampere into a diode for a controlled interval, then drop to 10 mA in nanoseconds, then sample the level within 20 micro or so. To get a snapshot of junction temp.
Gonna be both for a thermal paper and a veroboard pic for the other thread..
jn
anytime kindhornman.. thanks, and your welcome..
Seems an innocent oversight considering the obscurity of the previous material, no worse than certain folks claiming to have discovered slew rate and full power bandwidth limitations a decade after they appeared in data sheets.
Yes since maybe 30 years ago. It's not anything new.
Does "exotic" mean simply testing mylar films, poly caps and other non expensive caps?
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How does presenting anything so late in this 51,611 post thread teach anyone anything? I doubt anyone is going to wade through this thread to find your measurements ( when anything good is posted that is) or will even know they are here. Not many "amateurs" here now ya know although you like to think of everyone but yourself as one.
You are right, Kindhornman. IF you don't design audio for a living, then in my mind, you are an amateur. Of course, there are some exceptions, but very few in this crowd.
This is important, because when you do not face the challenges of making a successful audio design, it appears easier to do than it really is.
This is important, because when you do not face the challenges of making a successful audio design, it appears easier to do than it really is.
In a literal sense, that's absolutely true and I agree with John. Within his market niche, very few of us do design for money.
"Amateur" versus "professional" says nothing about knowledge or competence (there are superbly competent and incompetent examples of each), it's about whether one has a financial stake in something or other being correct.
"Amateur" versus "professional" says nothing about knowledge or competence (there are superbly competent and incompetent examples of each), it's about whether one has a financial stake in something or other being correct.
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