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  1. #91

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    Quote Originally Posted by jcandy View Post
    ... why was the completely non-specific word "noise" used rather than "mechanical resonance" ...
    The generic term "noise" had me thinking the reference was to some other mechanism than resonance.It's well known that capacitors can depending upon their construction ,be prone to vibrations and can even become microphonic.Thus the reason some hi end manufacturers go as far as to potting their xovers in epoxy.(I use generous amounts of hot glue or silicone.0
    I'll ask again,if he tests for it what is Darqueknight's testing methodology for this specific performance aspect?

    Now off to get a coffee and read Mr.Duncun's treatise on the subject.
    Last edited by FTGV; 04-08-2011 at 05:50 PM.

  2. #92

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    Whew! Back on track of the OP, thought it would never happen.

  3. #93

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    Quote Originally Posted by DarqueKnight View Post
    The only "big surprise" is that when you are clearly shown to be wrong, you still cling to your "beliefs" with religious fervor and tenacity.
    Baloney.

    Quote Originally Posted by DarqueKnight View Post
    1. You clearly did not have any knowledge, and understanding, of the noise generating mechanisms in capacitors until it was specifically pointed out to you. This was verified by your rash erroneous assumption that the authors did not correlate mechanical vibration to audible noise.
    Just wow.

    - I asked YOU for clarification of noise, because the standard use of "noise" in electronics is connected with thermal noise, and that is extremely small in the present context. So, you couldn't have meant noise in the usual sense, could you?

    - You were silent, but your commander-in-chief F1NUT put in his 2 cents and again used the mystery expression "noise" without clarification. Obviously, he didn't mean thermal noise, either. Go figure.

    - When pressed, F1NUT asserted that the noise was "mechanical resonance". I replied by saying that (a) I doubt that's what he meant, (b) it was a silly answer in any case because mechanical resonance is sound a capacitor (not the loudspeaker driver) makes, and has not been shown to alter the electrical signal the capacitor passes to the driver. The author of the mechanical resonance paper NEVER USES THE WORD NOISE, so I still do not believe F1NUT. I believe he used the word noise without ever knowing what it meant.

    - Next, you jumped on the noise="mechanical resonance" bandwagon, and brought up the Duncan paper again. In case you missed it, note that Duncan NEVER USES THE WORD NOISE. So, at this point you two look pretty guilty of pulling stuff out of your a$$es.

    Please, stop calling mechanical resonance "noise", and stop claiming mechanical resonance is anything more than capacitor buzzing, because nowhere is any connection made between mechanical resonance and some effect on the capacitance OR the sound coming from the tweeter.

    To measure audio capacitor performance, we're back to what actually matters: capacitance, series and leakage resistance, and dielectric losses.

  4. #94

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    Quote Originally Posted by audiobilly View Post
    Whew! Back on track of the OP, thought it would never happen.
    It finally happened but it sure didn't last long.
    SDA 2BTL Sonicaps Mills resistors RDO-198s New gaskets H-nuts Erse inductors Crossover upgrades by westmassguy
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  5. #95

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    Quote Originally Posted by jcandy View Post
    I asked YOU for clarification of noise, because the standard use of "noise" in electronics is connected with thermal noise, and that is extremely small in the present context. So, you couldn't have meant noise in the usual sense, could you?
    Yes, I could have and I did. I realize you are desperate to save face by deflecting the cause for your catastrophic misunderstanding to me and F1nut, but that's not gonna fly.

    Your understanding of "noise in the usual sense" is faulty. Actually, there is no such thing as (electrical) noise in the "usual" sense because electrical noise is a broad grouping of several types of phenomena. I don't think you can find one credible reference where the "standard" definition of electrical noise refers only to thermal noise.

    Quote Originally Posted by jcandy View Post
    -....but your commander-in-chief F1NUT put in his 2 cents and again used the mystery expression "noise" without clarification. Obviously, he didn't mean thermal noise, either. Go figure.
    F1nut is the Honorary President of Club Polk and a friend, but he is not my commander-in-chief. That title is reserved for the honorable fellow who signs my paycheck.

    I will share with you that he, and others, found it hilarious that a Ph.D. in physics would have such a one-dimensional understanding of electrical noise.

    Here is the help you have been pleading for. I can't guarantee that I will be able to be this generous in the future. If you are still not clear after the following explanations, then I urge you to use these as a springboard for further study...if you are able. Read further and get a clue.

    The following definition is from "Modern Digital and Analog Communications", 4th ed, 2009, p. 3, by B. P. Lathi and Zhi Ding. This textbook is widely used in United States undergraduate electrical engineering programs as the basic text for the first communication engineering course:

    1. "The signal is not only distorted by the channel, but it is also contaminated along the path by undesirable signals lumped under the broad term noise, which are random and unpredictable signals from causes external and internal."

    The Electronics Engineer's Handbook by Donald Fink, p. 17-3 (published way, way back in 1975) defined electronic noise this way:

    2. "Noise may be defined as any signal which does not convey useful information. Noise is introduced in measurement systems by mechanical coupling, electrostatic fields and magnetic fields. The coupling of external noise can be reduced by vibration isolation, electrostatic shielding, and electromagnetic shielding."

    Finally, here is Wikipedia's definition of electrical noise:

    3. "Electronic noise is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal and shot noise are unavoidable and due to the laws of nature, rather than to the device exhibiting them, while other types depend mostly on manufacturing quality and semiconductor defects."

    Link: Electrical Noise Definition on Wikipedia

    By the way, the Fink handbook has been in my personal library since I was a teenager. The Lathi communications textbooks (3rd and 4th editions) have been in my personal library going back 10 and 2 years respectively. Moreover, my numerous posts on electrical noise on this forum provide a public record that I am well aware of the various causes of external and internal electrical noise.

    Perhaps you need to rethink your (mis)understanding of the causes of electrical noise.

    Quote Originally Posted by jcandy View Post
    You were silent.
    There are numerous examples when I have asked you direct questions and you either side-stepped or ignored them outright. There are several such examples right here in this thread. I didn't bitch about it. I didn't complain. I didn't whine. You were just exercising your right not to answer a question posed in casual conversation.

    Why do you arrogantly believe that you are exempt from answering the questions of others yet others are obligated to answer your interrogatories?

    To clarify your misunderstanding, I was silent because it was glaringly obvious that you didn't know a damn thing about what you were talking about and that you would not understand the answer even if I provided it.

    Your gross misunderstanding of the concept of electrical noise, as evidenced by your own words quoted above proves this unequivocally!

    Quote Originally Posted by jcandy View Post
    Please, stop calling mechanical resonance "noise", and stop claiming mechanical resonance is anything more than capacitor buzzing, because nowhere is any connection made between mechanical resonance and some effect on the capacitance OR the sound coming from the tweeter.
    Again, since you either missed it or misunderstood it, this quote is from the Duncan 2009 paper, p. 2:

    "Duncan and Dodds in [6] have shown that the resultant acoustic emissions from some of the capacitors under ac current conditions have been found to be significant, and detrimental to the overall reproduced sound quality.

    This quote is from the abstract of the Duncan 2008 paper:

    "This paper gives an account of work carried out to assess the effects of metallised film polypropylene crossover capacitors on key sonic attributes of reproduced sound. The capacitors under investigation were found to be mechanically resonant within the audio frequency band, and results obtained from subjective listening tests have shown this to have a measurable effect on audio delivery.

    If, in the paper excerpts above, the authors are not trying to show a connection between capacitor mechanical resonance and sound quality coming from a loudspeaker, what are they trying to convey?

    Quote Originally Posted by jcandy View Post
    In case you missed it, note that Duncan NEVER USES THE WORD NOISE.
    They didn't have to. I knew what they meant. Go back and re-read the definitions I generously provided above. Since you are a highly educated scientist, I expected that you understood that common terms are not always used in professional literature. I didn't expect to have to spoon feed a Ph.D. in physics.

    Quote Originally Posted by jcandy View Post
    So, at this point you two look pretty guilty of pulling stuff out of your a$$es.
    Actually, the only things pulled out of an a$$ is your so-called, yet non-existant, "standard" definition of "electrical noise = thermal noise" and your a$$inine a$$umption that "the rated value of a capacitor is the only determinant of its sound quality".

    I know it's hard, but try to keep up and connect the dots:

    1. Capacitor Resonance=Capacitor vibration.
    2. Capacitor vibration=Detrimental effects on the charge/discharge capability of a capacitor.
    3. Detrimental effects on the charge/discharge capability of a capacitor=random fluctuations in the electrical signal passing through a capacitor.
    4. Random fluctuations in the electrical signal passing through a capacitor=Noise (according to definition 3 above).


    Have a good evening and a wonderful weekend.
    Last edited by DarqueKnight; 04-08-2011 at 09:21 PM.
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  6. #96

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    After trying to digest some of the more technical aspects of these arguments, I remember why I lost my scholarship in engineering at Georgia Tech--studying these issues was nowhere near as enjoyable as drinking a cold one while occasionally being around the aroma of green plants being burned with some great music and a lack of arguing.

  7. #97

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    Quote Originally Posted by DarqueKnight View Post
    1. Capacitor Resonance=Capacitor vibration.
    Resonance and vibration are two different things, just like damping and vibration. If you want to say a mechanical resonance gives rise to enhanced capacitor vibration, I think we can all accept that.

    Quote Originally Posted by DarqueKnight View Post
    2. Capacitor vibration=Detrimental effects on the charge/discharge capability of a capacitor.
    That is false. No data which shows a quantitative connection between mechanical resonance and capacitance has even been shown. All that has been shown are the somewhat borderline results of subjective testing of capacitors. This means that some other physical property of the capacitor may be the culprit (note that the ESR of the capacitors vary by more than a factor of three, so mechanical resonance as a variable has not been isolated).

    Quote Originally Posted by DarqueKnight View Post
    3. Detrimental effects on the charge/discharge capability of a capacitor=random fluctuations in the electrical signal passing through a capacitor.
    This is not even false, its gibberish. Resonance is non-random. Random fluctuations are the result of thermal noise. Typical detrimental effects, like ESR, or smashing the capacitor with a hammer, are non-random.

    Quote Originally Posted by DarqueKnight View Post
    4. Random fluctuations in the electrical signal passing through a capacitor=Noise (according to definition 3 above).
    3 is wrong, and random noise is thermal noise, not mechanical resonance. Resonance is a nonrandom phenomenon, and that's probably why nobody but you is calling mechanical resonance "noise". Give it up.

    Quote Originally Posted by DarqueKnight View Post
    Have a good evening and a wonderful weekend.
    You too, honestly. I think its a shame we're bickering.

  8. #98

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    Gentlemen Please,

    Is this a pontification of concepts? This is way of topic. The sum of real world experience here (on this forum) has, for lack of better words, value or merit. That is what the OP was looking for.

    One can not only use "tools" to determine a "possible" final outcome. Can you please start another thread, so there the ideas that have come forth be civilly debated?

    I do hope that Robint is still around. My goodness, what a simple question to ask, and then is this the real end result experience that this forum has to offer..?

    Just because a tool of measurement says no, that then means it would sound bad? Tools have their place, and "can" give us a good starting point. BUT, that does not mean that a measurement makes is sound good or bad. REAL world experience is the final answer.

    Love you all!

  9. #99

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    Quote Originally Posted by TennMan View Post
    It finally happened but it sure didn't last long.
    Man I love DK, and he is the man! Learned a lot from his input (knowledge). I, on the other hand, am not the man. jcandy just has to debate his point thou. This is not the thread to do so!

    IF we are to debate "that" subject, can we please just answer the OPs' questions and debate "that" on another thread?

    Very Good Debate, by no means. This is not the place.

    And yes, I do love you all. Ya'll have brought me a long way. Esp DK and TFL.

    XOXOXO!!!

  10. #100

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    Quote Originally Posted by troll
    Resonance is a nonrandom phenomenon, and that's probably why nobody but you is calling mechanical resonance "noise".
    Oh really? The folks at ClarityCap do.

    In all of the capacitors tested, resonances were observed in the upper audio frequency band between 10kHz and 30kHz, with varying mean amplitude and Q factor according to the particular capacitor under test. In most cases the emissions were clearly audible.
    Clearly audible means it's noise, sport!

    Quote Originally Posted by troll
    ....but your commander-in-chief F1NUT put in his 2 cents and again used the mystery expression "noise" without clarification. Obviously, he didn't mean thermal noise, either. Go figure.
    You are confused....again. I didn't use the word "noise" until my comment above. I posted a quote from the Sonicap site that used the word "noise". I know it is hard for you, but please try to keep the facts straight.

    Quote Originally Posted by DarqueKnight
    I will share with you that he, and others, found it hilarious that a Ph.D. in physics would have such a one-dimensional understanding of electrical noise.
    Indeed.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

  11. #101

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    Quote Originally Posted by DarqueKnight View Post
    The only "big surprise" is that when you are clearly shown to be wrong, you still cling to your "beliefs" with religious fervor and tenacity.

    CLARIFICATION: The underlined quote you cited above is not from the Duncan et al 2009 paper. It is from Duncan et al 2008, "Audio capacitors. Myth or reality?" Please try to keep your references straight. Otherwise, it makes it appear that you really didn't actually read the paper(s).

    You specifically said, regarding the Duncan 2009 paper:



    I specifically pointed out:





    It is obvious that it is you who does not understand the paper. You can engage in all the face-saving, side-stepping, red herring tactics you want, but the facts are:

    1. You clearly did not have any knowledge, and understanding, of the noise generating mechanisms in capacitors until it was specifically pointed out to you. This was verified by your rash erroneous assumption that the authors did not correlate mechanical vibration to audible noise.

    2. The authors show a clear link between mechanical noise in a capacitor and the creation of audible noise, contrary to your erroneous statement that they did not address this. Did YOU read the paper?

    3. For audio applications, we can assume that established, reputable manufacturers of capacitors know how to make them with good electrical properties. Therefore, as long as the capacitor is within its tolerance from rated value we do not need to be overly concerned with the electrical properties of the capacitor. We do need to be concerned about the audible effects of those electrical properties. If you are a music lover, you should have some concern about how the noise characteristics of a capacitor will affect the music signals passing through it.

    4. Contrary to your "beliefs", there are other things which affect a capacitor's sound performance in addition to its rated value.

    5. With regard to what the authors wanted to accomplish with the paper, they are quite clear (p. 2):

    "This work presented in this paper has focused on the use of metalized film capacitors in loudspeaker crossover applications and one of the main findings has been that the capacitors used in crossover applications exhibit varying degrees of mechanical resonance. Duncan and Dodds in [6] have shown that the resultant acoustic emissions from some of the capacitors under ac current conditions have been found to be significant, and detrimental to the overall reproduced sound quality."

    "...discussions with loudspeaker manufacturers, and anecdotal evidence from within the industry suggested that mechanical vibration and resonance phenomena in crossover capacitors has a detrimental effect on the quality of the reproduced sound. This has been confirmed by the authors in a series of detailed subjective listening tests, the results of which are presented in [6]."

    The conclusion section states (p. 9)

    "These results show a clear resonant peak for each of the capacitors in the upper audio frequency band between 14kHz and 22kHz indicative of a mechanical resonance at that frequency."

    Obviously, the authors of the paper are primarily concerned with the detrimental effects of capacitor mechanical vibration on SOUND QUALITY and not whether there is a link between mechanical vibration and the electrical properties of the capacitor.

    I think it is rather ironic that a paper that you offered (Duncan et al 2009) to supposedly debunk audiophile views of audible differences in capacitors actually strongly supports it.

    Question: You appear to believe that Duncan et al 2008, "Audio capacitors. Myth or reality?", also debunks the audiophile assertion that there are audible differences in capacitors. Is that your position?

    Do tell!!
    This is an excellent post DK. Just excellent.

    Greg

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    Quote Originally Posted by F1nut View Post
    Oh really? The folks at ClarityCap do.
    Where does ClarityCap call mechanical resonance noise? In the ClarityCap Research Summary

    Mechanical Resonance as a Determinant of Audio Signal Capacitor Sound Quality

    the word resonance appears 25 times, and word noise appears exactly 0 times. In the 2009 AES paper

    Forces in cylindrical metalized film audio capacitors.

    the word resonance appears 19 times, and word noise appears exactly 0 times.

    Quote Originally Posted by F1nut View Post
    Clearly audible means it's noise, sport!
    So a pure tone is noise? Fair is foul and foul is fair ...

    The topping on the cake is that there is no data that show a connection between mechanical resonance and capacitor performance. What we have are largely inconclusive subjective reports which by their very nature cannot distinguish between ESR, resonance, or a third unknown variable.

  13. #103

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    Quote Originally Posted by DarqueKnight View Post
    Question: You appear to believe that Duncan et al 2008, "Audio capacitors. Myth or reality?", also debunks the audiophile assertion that there are audible differences in capacitors. Is that your position?
    Of course there are audible differences in capacitors. Make the dissipation factor high enough and you'll get 100% ABX accuracy in blind testing. The problem is that for non-defective metalized poly audio caps, the transfer functions are so similar, and the dissipation factor so low, the subjective testing is, overall, inconclusive. For this reason, I take garden-variety assertions of one brand's superiority over another to be imagined not real.

    Duncan and Dodds say it best:
    The actual audio differences using two different metal film capacitors in the HF driver circuit of a first order crossover is very subtle and possibly only detectable by trained listeners who spend a lot of critical listening time evaluating and developing systems that they are very familiar with. As such, the listening tests posed significant challenges to both the investigators and listening panel.
    Last edited by jcandy; 04-09-2011 at 02:36 AM.

  14. #104

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    Well, I'm back. Very interesting thread, but way above my head. The reason I chose Axon was they were cheap. Both my Polk monitors cost less than $20, thrift store buys. But after following the thread and doing research I found this site.

    www.humblehomemadehifi.com/Cap.html

    He likes Audience Auricaps. So I bought 4 12uF caps at $12 a pop.

    Now the next question! How good do the caps need to be for the woofer. Do I follow Polk with 7A's, where they used a Mylar and then electrolytics for the woofer. At $5 for the four speakers or do I go all out and use polypropylene caps. e.g. Dayton or Jantzen.
    at $10 a speaker.

    I will now duck for cover and be back on page 8.

    Thanks

  15. #105

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    Quote Originally Posted by Robint View Post
    Well, I'm back. Very interesting thread, but way above my head. The reason I chose Axon was they were cheap. Both my Polk monitors cost less than $20, thrift store buys. But after following the thread and doing research I found this site.

    www.humblehomemadehifi.com/Cap.html

    He likes Audience Auricaps. So I bought 4 12uF caps at $12 a pop.

    Now the next question! How good do the caps need to be for the woofer. Do I follow Polk with 7A's, where they used a Mylar and then electrolytics for the woofer. At $5 for the four speakers or do I go all out and use polypropylene caps. e.g. Dayton or Jantzen.
    at $10 a speaker.

    I will now duck for cover and be back on page 8.
    Let me add that the Jantzen caps, which perform very well, are made in Poland. This may be an incentive depending on your opinions about trade and economics. I do my best to buy products manufactured in Canada/US/Europe, so this is the reason I lean toward Jantzen.

  16. #106

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    Quote Originally Posted by Robint View Post
    Well, I'm back. Very interesting thread, but way above my head. The reason I chose Axon was they were cheap. Both my Polk monitors cost less than $20, thrift store buys. But after following the thread and doing research I found this site.

    www.humblehomemadehifi.com/Cap.html

    He likes Audience Auricaps. So I bought 4 12uF caps at $12 a pop.

    Now the next question! How good do the caps need to be for the woofer. Do I follow Polk with 7A's, where they used a Mylar and then electrolytics for the woofer. At $5 for the four speakers or do I go all out and use polypropylene caps. e.g. Dayton or Jantzen.
    at $10 a speaker.

    I will now duck for cover and be back on page 8.

    Thanks
    I love Auricaps for coupling caps in tube amps.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

    Pass Aleph 30; Eastern Electric Mini Max; Adcom GDA600; MIT S3/Z Pc; SDA 1C; Squeezebox; Tubes add soul!

  17. #107

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    Quote Originally Posted by Robint View Post
    Now the next question! How good do the caps need to be for the woofer. Do I follow Polk with 7A's, where they used a Mylar and then electrolytics for the woofer. At $5 for the four speakers or do I go all out and use polypropylene caps. e.g. Dayton or Jantzen.
    at $10 a speaker.

    I will now duck for cover and be back on page 8.

    Thanks
    I'm glad that concerns about you being "run off" have been found to be untrue.

    Some of us who have years of experience modifying speaker crossovers have found that sound improvements can be realized by also upgrading the shunt capacitors in the low frequency part of the crossover. Where possible, I like to use the same level of cap in the low frequency section as the high frequency section, although this is not always possible because of the large capacitance values sometimes required in the LF section.

    When I did my first crossover upgrade in 1990, under advisement from Polk's engineering department, they recommended replacement of the mylar and electrolytic capacitors with high quality polypropylene film capacitors. They also advised that the silver mica bypass capacitors would not be needed with the polypropylene capacitors.

    The best advice I can give is to search the forum and the Internet for reports from others who have done similar upgrades with the 5 and 7A. This thread has over 1200 views. Due to the apparent level of interest in this subject, there has to be a few people around who have done something similar with the 5 and 7A.
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
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    Quote Originally Posted by jcandy View Post
    I think its a shame we're bickering.
    I'm not bickering. I'm just explaining my point of view during a casual conversation.

    Quote Originally Posted by jcandy View Post
    So a pure tone is noise? Fair is foul and foul is fair ...
    You would not have asked this question if you actually had a good understanding of electrical noise.

    Yes, under certain circumstances, a pure tone can be noise. For example, a 60 Hz hum induced in a loudspeaker's output by an appliance motor or lighting is noise. An insect buzzing in one's ear at a specific frequency (pure tone) is noise. Noise can be random, nonrandom or pseudo-random. I provided three definitions of electrical noise in post #95. One of which was this:

    Quote Originally Posted by DarqueKnight View Post
    The Electronics Engineer's Handbook by Donald Fink, p. 17-3 (published way, way back in 1975) defined electronic noise this way:

    "Noise may be defined as any signal which does not convey useful information."
    The definition above is similar to one found in "Electromagnetic Compatibility Engineering" by Henry Ott (Wiley, 2009). This book is considered to be an authoritative text on the subject of electrical noise. Mr. Ott teaches on page 3:

    "Noise is any electrical signal present in a circuit other than the desired signal."

    Mr. Ott teaches on page 4:

    "Noise sources can be grouped into the following three categories: (1) intrinsic noise sources that arise from random fluctuations within physical systems, such as thermal and shot noise; (2) man-made noise sources, such as motors, switches, computers, digital electronics, and radio transmitters; and (3) noise caused by natural disturbances, such as lightning and sunspots."

    Quote Originally Posted by jcandy View Post
    The topping on the cake is that there is no data that show a connection between mechanical resonance and capacitor performance. What we have are largely inconclusive subjective reports which by their very nature cannot distinguish between ESR, resonance, or a third unknown variable.
    Electrical engineers have done some research in this area. One example is the following paper:

    Robert Nelson and Lincoln Davidson, "Electrical Noise Generated from the Microphonic Effect in Capacitors", Proceedings of the 2002 IEEE International Symposium on Electromagnetic Compatibility, Minneapolis, MN, August 2002.

    Nelson and Davidson teach (p. 855, abstract):

    "Some capacitors also exhibit an electrical response when stressed physically. This response con be significant."

    From page 860 of Nelson and Davidson 2002 (conclusion section):

    "It has been shown that capacitors can exhibit significant noise currents and voltages when subjected to physical stress. This initial conclusion may prove helpful to circuit designers of systems that are likely to experience vibration (such as off-road vehicles). It is clear that the noise response of capacitors is very dependent on the type of material used in capacitor construction, with high-dielectric ceramic capacitors (like X7R) being considerably noisier than COG or PPS capacitors. However, when DC bias voltages are applied to ?quiet? capacitors the electrical noise response can increase significantly. Noise response was also affected by the physical location of the capacitor on the board." [Underlined emphasis mine.]

    Quote Originally Posted by jcandy View Post
    Resonance and vibration are two different things, just like damping and vibration. If you want to say a mechanical resonance gives rise to enhanced capacitor vibration, I think we can all accept that.
    I think that most knowledgeable people reading my comment know what I meant. It was a form of conversational shorthand. The concept is similar to that used in the following statements:

    "Milk = strong bones and teeth."
    "Cocaine = poor health"

    Of course, milk is a liquid and bones and teeth are hard biological constructs, therefore they cannot be "equal". It would be understood by most people reading this that the idea conveyed is that the consumption of milk improves the prospect of healthy bones and teeth. A similar line of reasoning would be used for the "cocaine" statement.

    The terms "resonance", "vibration", and "oscillation" are sometimes used interchangeably by electrical engineers. Another term used is "resonant noise".

    Hope this helps.
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
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  19. #109

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    Quote Originally Posted by DarqueKnight View Post
    Robert Nelson and Lincoln Davidson, "Electrical Noise Generated from the Microphonic Effect in Capacitors", Proceedings of the 2002 IEEE International Symposium on Electromagnetic Compatibility, Minneapolis, MN, August 2002.

    Nelson and Davidson teach (p. 855, abstract):

    "Some capacitors also exhibit an electrical response when stressed physically. This response con be significant."

    From page 860 of Nelson and Davidson 2002 (conclusion section):

    "It has been shown that capacitors can exhibit significant noise currents and voltages when subjected to physical stress. Noise response was also affected by the physical location of the capacitor on the board." [Underlined emphasis mine.]

    I want to clarify what Nelson and Davidson meant by "physical stress".

    From p. 855:

    "In this work the capacitor under test is viewed as a noise source, and the electrical noise created by physically stressing the capacitor is being examined.

    The physical stress applied to the capacitor was a simple "flick" of a finger."


    From p. 856

    "Further testing was carried out using a vibration table at Phoenix International (a subsidiary of John Deere Corporation).

    The setup shown in Figures 4 and 5 was used to vibrate the board vertically. Horizontal vibration was also tried, but the responses were less pronounced (but still present) and are not presented."


    From p. 857:

    "In all tests the frequency of vibration was swept from 100 to 1000 Hz."

    From p. 857 regarding mechanical resonance effects on induced capacitor electrical noise:

    "Note that the frequency of the dominant response is the same (i.e., the board resonance), but the magnitude of the noise current in the circuit mounted in the center is roughly three times that mounted near the edge. It is assumed that the capacitor mounted near the edge is likely to experience less vibration than the one in the center."

    For readers interested in a further discussion of methods used to control vibration in electronic circuit boards, I would refer them to:

    B. Esser and D. R. Huston, "Active Mass Damping of Electronic Circuit Boards.", Journal of Sound and Vibration, Volume 277, Issue 1-2, 419-428, October 2004.

    Since capacitors have been shown to generate electrical noise in the presence of vibratory environments, one can wonder if certain capacitors are more resistant to vibration than others. For example, in a group of polypropylene film capacitors with roughly the same basic electrical measurements, some might exhibit better resistance to mechanically induced noise due to their construction characteristics. Is this reasonable?

    Enjoy your readings.
    Last edited by DarqueKnight; 04-11-2011 at 07:28 PM.
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    Quote Originally Posted by DarqueKnight View Post
    The terms "resonance", "vibration", and "oscillation" are sometimes used interchangeably by electrical engineers. Another term used is "resonant noise".

    Hope this helps.
    Making up your own terminology and passing it off with a straight face does not help to do anything but obfuscate what we're talking about. I would never use the word noise to refer to mechanical resonance, any more than I'd use the word noise to refer to cone breakup or IMD or any other sort of well-known resonant phenomenon that is deterministic. We have very specific words for all these things. The authors of the defining papers never once used the word noise to refer to mechanical resonance, so what possible cause are you helping?

    In reality, using "noise" is doubly misleading, because no connection between mechanical resonance and the proper function of the capacitor has been shown. It is possible that there is no negative sonic consequence of mechanical resonance. It is possible that the very-subtle-to-null results of subjective testing (remember that round 1 uncovered nothing significant) were the result of differing ESR rather than resonance.

    So, you can call it noise if you want to. Just don't expect anyone, including Duncan himself, to have any idea what you are talking about.

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    Quote Originally Posted by jcandy View Post
    So, you can call it noise if you want to.
    Thanks for allowing me that indulgence.

    I will also graciously allow you the indulgence of believing that electrical noise is only due to random processes, electrical noise is only due to thermal effects, and there is no relationship between mechanical resonance and the audible performance of capacitors.

    Quote Originally Posted by jcandy View Post
    Just don't expect anyone, including Duncan himself, to have any idea what you are talking about.
    My fellow capacitor mystics knew what I was talking about.

    Quote Originally Posted by jcandy View Post
    In reality, using "noise" is doubly misleading, because no connection between mechanical resonance and the proper function of the capacitor has been shown. It is possible that there is no negative sonic consequence of mechanical resonance.
    Oh sure, it might be possible. What theoretical foundation are you basing this newest assumption on? In other words, what level of electrical noise is audible in stereophonic audio circuits? Do tell!!

    I ask because, first you asserted that there was NO DATA to show a relationship between mechanical resonance and capacitor noise. Then, when citation to a paper providing such data was offered, you come back with that old audio naysayer cop-out:

    "Yeah, the difference is there, but it's not audible"

    Quote Originally Posted by jcandy View Post
    Making up your own terminology and passing it off with a straight face does not help to do anything but obfuscate what we're talking about.
    Well, people who actually have some knowledge in this area, as you purported to, knew what I meant. I think the more egregious obfuscation was due to your dogmatic insistence that:

    1. Electrical noise can only be characterized by random processes.
    2. The"standard definition" of electrical noise is thermal noise.
    3. There is NO DATA showing a relationship between mechanical resonance and electrical noise in a capacitor.

    Quote Originally Posted by jcandy View Post
    ...what possible cause are you helping?
    The answer to that should be glaringly obvious by now.

    Good night.
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
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    Quote Originally Posted by DarqueKnight View Post
    Well, people who actually have some knowledge in this area, as you purported to, knew what I meant. I think the more egregious obfuscation was due to your dogmatic insistence that:

    1. Electrical noise can only be characterized by random processes.
    2. The"standard definition" of electrical noise is thermal noise.
    3. There is NO DATA showing a relationship between mechanical resonance and electrical noise in a capacitor.

    The answer to that should be glaringly obvious by now.

    Good night.
    1. I have never even used the expression "electrical noise". I said thermal noise is random noise. I said that because thermal noise is, in fact, random noise.
    2. Its unlikely that I defined "electrical noise" since I never used the expression. I did once ask for clarification of what YOU meant by noise, because noise in electronics is normally taken to mean thermal noise. That would explain why FTGV also thought that YOU meant thermal noise.
    3. According to your use of English, they are the same thing ex vi termini.

    Unless somebody brings something new to the table, we should pronounce the horse dead.

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    Is Ripple considered a Noise in capacitors?

    Although ripple is usually extremely small in the Film caps, and other small value capacitance of various caps (except electrolytic); ripple can be quite large and quite a problem with electrolytic of various values.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone.

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    Quote Originally Posted by megasat16 View Post
    Is Ripple considered a Noise in capacitors?
    Capacitor ripple current and voltage represent the rms value of unwanted residual AC current and voltage in the DC output of a capacitor. Ripple is a type of electrical noise.

    From "The Electronics Engineer's Handbook" by Donald Fink (McGraw-Hill, 1975), p. 17-3:

    "Noise may be defined as any signal which does not convey useful information."
    From "Electromagnetic Compatibility Engineering" by Henry Ott (Wiley, 2009), p.3:

    "Noise is any electrical signal present in a circuit other than the desired signal."
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
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    OMG!!!!! I can't believe you used the word Noise again.

    DK, thank you for your thoughtful and thorough explanations.
    Quote Originally Posted by Timothy Smith View Post
    WOW!

    That's like working your way through Katie Perry in order to get to Rosie O'Donnell.

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    Quote Originally Posted by Joe08867 View Post
    OMG!!!!! I can't believe you used the word Noise again.
    Four more times!!!

    Quote Originally Posted by Joe08867 View Post
    DK, thank you for your thoughtful and thorough explanations.
    Thoughtful and thorough? But...but...but, I was trying to be obfuscating.

    Quote Originally Posted by jcandy View Post
    Making up your own terminology and passing it off with a straight face does not help to do anything but obfuscate what we're talking about.
    Obfuscate- 1. to confuse; bewilder, stupefy. 2. to darken; obscure. Syn. perplex.
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
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    Talking

    Maybe you guys could get your own forum "Vibrating Capacitors". Then you could go on insulting each other and the rest of us could look in just briefly for a vocabulary lesson.

    I'm glad the OP came back and I apologize for the behavior of some members. Some are very knowledgeable but they get carried away and can't control their impulses.
    TO ERR IS HUMAN. TO FORGIVE IS CANINE.

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    Quote Originally Posted by DON73 View Post
    Maybe you guys could get your own forum "Vibrating Capacitors". Then you could go on insulting each other
    I don't believe DK has insulted Jcandy, I'd say it's the other way around.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

    Pass Aleph 30; Eastern Electric Mini Max; Adcom GDA600; MIT S3/Z Pc; SDA 1C; Squeezebox; Tubes add soul!

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    It's been said that a picture is worth a thousand words. Most everything that has been said in this thread could be condensed down to one picture.

    SDA 2BTL Sonicaps Mills resistors RDO-198s New gaskets H-nuts Erse inductors Crossover upgrades by westmassguy
    Adcom GTP-450 preamp
    Adcom GFA-555 amp Upgrades & speaker protection added by OldmanSRS
    Pioneer DV-610AV DVD/CD player
    SDA CRS+ Hidden away in the closet

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    Quote Originally Posted by DarqueKnight View Post
    Capacitor ripple current and voltage represent the rms value of unwanted residual AC current and voltage in the DC output of a capacitor. Ripple is a type of electrical noise.
    It's what I thought too but let's hear what our other Prof thinks.

    Mechanical resonance or vibration is quite troublesome for the capacitors of the larger value and size especially when put inside a speaker enclosure and bombarded with constant shaking and causing capacitors to premature failure depending on the construction technique of such capacitors. I haven't really studied the effect of mechanical resonance in capacitors and the noise increase in the capacitors as you and Jeff are debating but it's worth getting a scope out and measuring the noise figures in the capacitors.

    I think you are carrying out the investigation in your lab so I'll just read up when you are done.

    Anyway, you know Physicists are headstrong but loveable, right?
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone.

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