David12 when I wrote the thread my feelings is that audio is a good hobby , second is I do respect everyone who are Agon members, third I know most of us are capable to give courtesy and respect each other, I agree my thread is just to remind members we are all cool here, it can get better, so far it did it’s porpuse..So enjoy agoners...
Please Read and express your feelings and opinions....
I noticed that lately or maybe for the last five yrs, there is so much arguments,name calling, attacking cables , speakers , components makers and more, more of disagreement with members, even Audio dealers are being attack here...Very few know how to apologize when they are wrong.What can we do as Audiogon members to improve our communication to each other? How to give the informations, recommendation to members who need it? This is without involving Audiogon, any opinion or ideas , For me this is fun and place to learn in audio...thank you all
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@whart. PLUS 1. @david12 , Not all of the trolls here are pushing an agenda for commercial reasons. The worst, for me, are the trolls who argue what our ears tell us, such as differences in power cords, as an example, and brought up again very recently on a fairly new thread. They say we are imagining it, hallucinating, off our rockers. And, they keep coming back, again and again and again. There are other types, too, such as those that bash one product design vs. another ( in my case, horn loaded speakers ). I have never jumped on a thread and bashed anything. I have been here on the Gon for 10 years, and this has gotten worse. I find them annoying, but most of all, I have no respect for them, because this is a forum about " listening to music ", and they rely only on science, and / or on " their " godly beliefs.. How I see it, anyway. I just laugh most of the time at these ignorant, close minded, earless people. Enjoy ! MrD. |
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I have to agree with the original post, standards of courtesy do seem to be dropping. I try to post my opinions and make clear they are opinions, not facts and then try to accept other peoples opinions. I have'nt experienced much vitriol. only once I can recall clearly. I expressed that I was'nt that impressed by Magico Speakers after a prolonged listen at a show. The gist of the reply was I could'nt give an opinion unless I had experienced them for some time, weeks certainly, in my own home. It plainly is'nt possible to audition everything in your own home, especially a product you can not afford and have no intention of buying. That is simply unfair on the dealer. I thought the response was just plain stupid, but did'nt say so and was not mortified. We should just expect opinions and advice is given in good faith. Now I know there are trolls around, people pushing an agenda for commercial reasons. Unless that is clear, I just accept peoples posts are in good faith.. Please don't assume all members are from the US of A, I'm from the UK. We have the same problem here.On the PinkFish site, make a favourable comment on the benefits of cables and you are likely to find men in pointy hats and a burning cross on your front lawn next day. |
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Geoff- Making the complex simple is an art. I don’t think the problem is confined to the hard sciences. My technical knowledge is spotty, and mostly learned from experience, though I’ve certainly read a fair share, and when the need arises, I ask questions. Most people seem to be pretty gracious in sharing their knowledge unless there is something proprietary involved. (I’m now speaking as a hobbyist, not a lawyer-- I’m retired anyway, but I teach at the university level and it is a challenge to impart knowledge even to smart, ambitious students). The other thing about audio, and here I’ll probably enter into the ’no go’ zone is that the end result of what i’m listening to is more than a bunch of equations or formulae. I’ve got to take into account room acoustics, gear set up, the source material (which is a huge variable in my experience). When it all works, it is akin to magic, even if there are scientific explanations for what I’m experiencing. I live for those moments of musical transcendence. The gear is just the machinery to get there. |
@geoffkait This problem is so acute that in some fields they have a sub specialty. Translational medicine for instance aims to bridge the gap between patient treating doctors and medical researchers. Improving how information flows from one to another. https://en.wikipedia.org/wiki/Translational_medicine In my day job about half of what I do is this, translating between software developers, reliability engineers and business people so that the teams are fully engaged and unblocked. The rest of the time I'm just a jerk. Best, E |
whart The trick, to me (given that I am somewhat challenged in the math/physics/hard sciences department), is to translate the science into something that is readily understandable by those untutored in the relevant fields. I know that can lead to oversimplification but my experience working with witnesses as a lawyer is that the judge (and jury) needs to understand it. >>>>I think you just put your finger on it. According to what I’ve been seeing on audio forums for nigh on twenty five years there’s a huge communication barrier between science minded individuals and the rest the general population, including English majors, Econ. Majors, History majors, what have you. It just doesn’t compute. Even drawing a picture doesn’t work. That’s what Richard Feynman tried to do, somewhat unsuccessfully. Does that seem too harsh? |
The trick, to me (given that I am somewhat challenged in the math/physics/hard sciences department), is to translate the science into something that is readily understandable by those untutored in the relevant fields. I know that can lead to oversimplification but my experience working with witnesses as a lawyer is that the judge (and jury) needs to understand it. I think there is a certain mix of science or tech blended with communication skills that makes a big difference in how the message gets delivered and received. One can have a healthy argument without personalizing or belittling. There is also a fair amount of psychoacoustic stuff going on in audio, beyond the gear and its technical performance. That can be "tested" too, I suppose, but to me, there is an art to applying the science in a way that delivers the goods: one example- I like Vlad Lamm's SET amplifier. Its sonics had to do with some deliberate choices Vlad made beyond the specs. Is it magic? No. I think a lot of us have gaps in our knowledge and are open to learning. I know I am. I welcome information and healthy debate. Knocking heads doesn't help anybody, least of all contributors who probably have other, better things to do with their time. |
@almarg Namely that if the input power to a speaker is changed by a given number of db, SPL at a given listening distance will change by the same number of db It’s frankly hard to tell what cj was talking about, but I think what his problem was he couldn’t wrap his head around the delta dB being the same across V, W and SPL and that this was expressed in the separate coefficients (20 vs. 10) used in the dB formula. In the same way you can have different power calculations, and each be correct: P = V x A P = ( V x V ) / R Honestly, if these formulas weren’t equivalent, I’m not sure amplifiers could work! This tight interrelationship just blew cj's mind. On another note, Erik, thanks for injecting some sorely needed humor into this thread, with the donuts post :-) Haha! I thought everyone missed that. Best, E |
I very rarely or if ever have posted here. But I have seen it also. The anonymity on the internet sometimes brings out the worst in us. We can say things and do things that we might now otherwise do or say if we were all in the same room. What is a wonder to me is are we not all here for almost the same reason. We have more in common than not when it comes to audio. We like music, we like good audio. Many times it's not that we express our opinion it is how we express our opinion. I tell my kids. "It's not what you said. It is how you said it.". We really all don't know each other, so it is hard to read audiogon posts where people assume other audiogon members are lying or not telling the truth. I can't remember in my life when arguing ended up with a good result. A good discussion yes, but arguing brings up bad feelings. Well that is my rant. |
Like a few of us or the many of us who buy/sell/trade here on A’gon I have endeavored since my start on the site to maintain a degree of civility in the forums I participate in not only because most of them manage to be civil anyway, but also to complement my feedback score. I find that such goes pretty much hand in hand. When arguments/dialogues/exchanges here become less than civil it can become tiresome to say the least. However I have witnessed some incredibly funny, witty, and intelligent back and forths between and amongst members that are highly entertaining for me - and very possibly for them too. Are many audiophiles too serious? Indeedily. Personally, I’m an “audiot”, I don’t know a mosfet from a misfit but I have learned, and occasionally retained, some of the information I’ve read and received here, and all for the betterment of my enjoyment. When a forum becomes a contest with name calling and insults I simply scroll past them or abandon it for awhile. I don’t believe censoring posts that I may find offensive will correct such behavior. Free speech is free, intelligent speech costs none the more, it all depends what’s in yer moral wallet to begin with. |
@fleschler I think negative feedback is one of those very misunderstood things. Not to say that I understand it. For my purposes, it's a good thing. The F5 I built uses a generous amount of it, and yes, it does complicate the distortion spectrum, but the artifacts are down below -120dB. That seems like a good trade off for lowering the overall distortion a good bit for the power I'm demanding of that thing. On top of that, the amp is completely stable into loads well below what any normal speaker will exhibit. I always keep an eye out for amp descriptions that suggest "no feedback", "no loop feedback", or "no global feedback". I assume that if they're qualifying the type of feedback, then they're using some kind of negative feedback such as degeneration. |
Regarding the debate about the relation between SPL and speaker input power, I found the following sub-page at the site which provided the calculators that were referred to earlier: http://www.sengpielaudio.com/calculator-efficiency.htm Entering various parameters into either of the two calculators closest to the bottom of that page (one entitled "Sound Pressure Level and Amplifier Power" and the other in the section entitled "Electro-Acoustic Sensitivity") clearly confirms what Atmasphere, Erik_Squires and I have all said on this subject. Namely that if the input power to a speaker is changed by a given number of db, SPL at a given listening distance will change by the same number of db. (As previously stated, this of course assumes that the speaker is not being driven hard enough to cause thermal compression in the drivers to become significant). I also found the following writeup at PSB’s site, which provides additional confirmation. About 2/3 of the way down the page a table is provided showing power vs. volume for an unnamed 87 db speaker used as an example. Note that 40 watts results in a volume of 103 db, while a 6 db reduction in that power level (to 10 watts) results in a volume that is 6 db less (97 db). While a 3 db change in power, from 1 watt to 2 watts, changes the volume by 3 db, from 87 db to 90 db. And a 20 db change in power, from 1 watt to 100 watts, changes the volume by 20 db, from 87 db to 107 db. http://www.psbspeakers.com/articles/Guide-to-Speaker-Specifications On another note, Erik, thanks for injecting some sorely needed humor into this thread, with the donuts post :-) Regards, -- Al |
@almarg My comment was seconded in that thread by Erik_Squires, who is particularly knowledgeable and experienced in speaker design. You are far too kind. I’m not as knowledgeable as many others, and I certainly make my share of public mistakes. I hope that despite this I leave plenty of room for people to enjoy what they enjoy without imposing my own biases. I’m sure after this endorsement I’ll suffer a relentless series of public mistakes to make up for it. I will say that I often use XSim to double check my math. Speaker building is not my day job and I am far rustier than I used to be on this, so whenever I’m in doubt, I whip up a sample circuit, and pull up the relevant charts to validate my work. I encourage others to do the same, and frankly, if you have speaker building (or even mere speaker wiring) questions, take your questions and XSim schematics over to DIYAudio: http://www.diyaudio.com/forums/multi-way/ where the XSim author, Bill Waslo, and many many other more knowledgeable and opinionated speaker builders hang out. I daresay you’ll find many there who know more than me, but certainly not any with stronger opinions! :) Best, E |
Back to the discussion of zero feedback tube amps. I agree that they may sound good with certain speakers. The EAR 890 with 70 watts Class A power nearly oscillate when paired with Legacy Focus speakers with their low and non-linear impedance curve. However, the EAR 890 sounded just fine on the Legacy Signature IIIs which have a smoother curve and 1 ohm higher bass impedance. Same pre-amp and CD sources, wiring and cabling. Geoff-I demagnetize all CDs prior to play with the Walker Talisman. It's easy and it works for me. The other tweaks I haven't tried or have an interest in. |
CJ1965 4-20-2018I'm not sure what you are referring to. The only graph on the page addressing db conversion that Erik linked to is this one, and it just deals with voltage, not power. In any event, if (as it appears) you are saying that a 6 db reduction in electrical power into a speaker results in a 3 db reduction in SPL at a given distance, rather than resulting in a 6 db reduction in SPL at that distance, we'll have to agree to disagree. Regards, -- Al |
I believe that the references to force in this discussion are unnecessary and are contributing to confusion, and I believe that Atmasphere is correct. A short while ago I posted as follows in the other thread I referenced above, in relation to this matter: - almarg Look up the formula for sound power. It is defined by a force exerted over an area and assigned a vector (dot product). The formula for electrical power consumed is entirely different and far simpler - based on measured voltage and current. Understanding the distinction between the two is what provides the necessary insight to explain why efficiency is increased when voltage is DIVIDED (series) among loudspeaker drivers and remains unchanged when SPREAD (parallel) across the same driver. This is trivial first year electrical engineering subject matter. I can’t help the fact that you don’t understand it - regardless of your so called "credentials", "qualifications", or number of posts on Audiogon. To pay adequate deference to the people who developed this body of knowledge, you have to pay attention to things like units. Mixing and matching units in these equations results in obvious error. Again, the formula for sound power is readily available on Wikipedia for all to see. It involves applied force and area which dramatically alters the net resulting analysis. Electrical power input is totally separate and distinct and you cannot ASSUME the two are equivalent. There’s a reason the graph shown in the web page for db conversion that Erik linked to has a value of -6db for voltage gain/loss and -3db for sound power. One look at the two formulae for sound power and electrical power will explain why if you care to devote the time to examine them closely. And with that, I’m done attempting to set the record straight. All I get are insults for my trouble. No good deed ever goes unpunished. |
I believe that the references to force in this discussion are unnecessary and are contributing to confusion, and I believe that Atmasphere is correct. A short while ago I posted as follows in the other thread I referenced above, in relation to this matter: Almarg 4-20-2018My comment was seconded in that thread by Erik_Squires, who is particularly knowledgeable and experienced in speaker design. An excerpt from his post: Erik_Squires 4-20-2018Regards, -- Al |
Really? Are you serious? What do you think voltage is, my friend? Voltage is "electro motive FORCE". Halving the voltage does not reduce the force to 1/4. It reduces power to 1/4 since the formula for power expressed simply with voltage and resistance is:The problem here is that voltage does not exist without current. The two together are power. Even though we refer to speakers as 'voltage driven' that is a bit of a charged term (referring to the fact that many amplifiers are designed to act as 'voltage sources' and many speakers are designed to expect a voltage source to be driving it); but in fact power is actually making the speaker move. If you can somehow make a speaker move with voltage but *without* current, you will have a new branch of physics :) A 3db reduction is halving amplifier power, which is what drives a loudspeaker. Its the 'force' that makes a speaker move and because of that if you reduce the voltage by half, the power to move the speaker is reduced to 1/4 of previous. |
" Again, halving the **voltage** reduces the force to 1/4th. " - atmasphere Really? Are you serious? What do you think voltage is, my friend? Voltage is "electro motive FORCE". Halving the voltage does not reduce the force to 1/4. It reduces power to 1/4 since the formula for power expressed simply with voltage and resistance is: V squared divided by resistance. Look, I didn’t come here to give lectures on Electrical Theory Basics. This is getting embarrassing. Please review your textbooks. I can’t continue to carry on a technical conversation with you if you fail to grasp the basics. |
You’re using the wrong formula - equating electrical power to sound power. The db formula for sound power is :I was using the right formula as I was referring to amplifier power, not sound pressure and was pretty clear about that. When you halve the force and double the area, you wind up with roughly the same sound power that you began with. But improved acoustical coupling with increased area improves net efficiency (electrical power in versus sound power out).Again, halving the **voltage** reduces the force to 1/4th. |
@atmasphere You’re using the wrong formula - equating electrical power to sound power. The db formula for sound power is : 10 X log 10 (P/Po) db where P is the measured sound power and Po is the reference level. If you doubt me, look it up. I believe it’s spelled out pretty clearly in Wikipedia. And sound power is a function of the force applied, (in this case the voltage) along with the area and displacement over which that force is applied. When you halve the force and double the area, you wind up with roughly the same sound power that you began with. But improved acoustical coupling with increased area improves net efficiency (electrical power in versus sound power out). |
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You see, sir, that's how science works - full disclosure of the details.Hm. Something that article certainly lacked! Based on what you say here, you don't think a little disclosure would have been a good idea? That certainly **seems** what you are saying; if anything, this should have been an objection that you raised about this article rather than stand behind it. Why the contradiction? Are you needing to make others wrong so much that you are willing to contradict yourself? This slight on your part is a bit of hand waving. As for your other claims regarding what I've posted elsewhere, they don't even merit a response.Hm. You made the claim that when you cut the voltage applied to a speaker in half, its a 3db reduction. Here's the math: 2.83 volts is 1 watt into 8 ohms. I hope we can agree on that... So 1/2 of 2.83 volts is 1.415 volts. Using Ohm's Law, to calculate current we divide 1.415 with 8 ohms and we get 0.178975amps. Power is equal to amps x current, now we know the current so: 0.178975amps x 1.415volts = 0.25 watts. That's a 6 db reduction, not 3 db. Do you still think it does not merit a response, like- 'oh, I meant 'power' not voltage'? You were being pretty specific about voltage on that thread; perhaps you could clear that up. |
Those who may be interested in some background underlying the exchanges above between Ralph (Atmasphere) and CJ1965 will find the following thread to be relevant, beginning with the post by Atmasphere on 4-17-2018 and continuing to the end of the thread: https://forum.audiogon.com/discussions/a-question-on-speaker-driver-efficiency I believe that the posts in that thread by Ralph, CJ1965, me, and others will provide readers with a good perspective on the various protagonists. Regards, -- Al |
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So far no name calling, ideas and feeling we’re expressed, no heated conversation yet, I have not check this thread for quite a while, because of Axpona 2018, I attended for three days met some members here , told yah, they are much cooler in person...I would just like to add that, sometimes we don’t hear things the way they are. But we hear things the way we are, isn’t it? Ahah..I like to hear things the way they are....Yes we can get along....😀 |
@cj1965 Its pretty obvious here who's doing the hand waving. You can't back up your statements with either measurements or math. You committed some pretty obvious errors in your math on another thread in this section; maybe you might consider owning up to that- it would improve your credibility if you could admit your mistakes. |
I’ve tried no feedback amps and am dissatisfied with their sound (they were also Class A type).A lot depends on the load impedance and how the speaker is set up. To really get by without using feedback, the speaker has to be in on the idea. If not, tonal aberrations will occur. For more info: http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php Hey Koss, measuring and counting is only for the doubters and haters like this guy - Unfortunately, the article linked is a source of misinformation. The reason is the article lacks a listing of the equipment used. The most we get is a photo of a 70s machine, which maybe might be the same as the 'first class deck' mentioned (one wonders why this obvious omission was made- was he embarrassed by his playback apparatus?); no mention whatsoever of the phono equalizer(!), all of which have an enormous effect on the results, yet the results are construed to seem as if they apply to all LPs and LP reproducers when such obviously can't be the case. Wouldn't you want to know what is possible, rather than the results of 1960s tech? Here is an example of what I mean: The standardised groove geometry on an LP record is of a 2 thou* groove on a 5 thou spacing (the latter being based on 200 grooves per inch). As the diagram right illustrates, the absolute maximum modulation of a groove is ±1.5 thou which is equivalent to 76μm pk-pk modulation.The above statement is false- LP reproduction has advanced since the early 60s when this statement was more truthful. Cartridges of the period were horrific and variable groove spacing only arrived in the 1970s (and of course, without variable groove spacing you could simply set the lathe for less than 200 grooves per inch... sheesh!). We use 2 mil modulation as 0VU reference as we are conservative- our 'antiquated' 1980s Technics SL1200 equipped with a lowly Grado Gold (which we use to make sure that a cut we are working on will be playable by the garden variety machine) can manage 3db more than that without complaint; the upper limit is obviously higher than described in the above quote and that's with cheaper gear. Newer arms without engineering bugs like the Techincs arm can do even better. On the flip side (if you will pardon the expression) it turns out that much of the noise floor in LPs has to do with the pressings, not the lacquers, of which the latter have noise floors that are easily in the high -80s or low -90s (since the phono reproducer itself is actually the noise floor if the cutter head and stylus temperature are optimally set). At least one pressing house (QRP, associated with Acoustic Sounds in Salinas, KS) has found that by eliminating vibration in their pressing machines during cooling, the noise floor of the LP surface is dramatically reduced, approaching that of the lacquer. None of the test recordings for this article were made on such pressing machines, as QRP has only had them working in the last 5 years or so. I think that getting good measurements is great, but this article is an example of Bad Science- IOW fake news. |
Wow.....Geoff is silent for more than 4 hours, is that a record? .Did I say something to offend him? I certainly wouldn’t want to "hurt his feelings". We all have "feelings" that need to be respected and protected in "safe spaces"....not the "padded cell" safe spaces mind you, just the soft cozy safe spaces where folks can be free to "express their feelings" without anyone being skeptical or passing judgment. |
@kosst_amojan Hey Koss, measuring and counting is only for the doubters and haters like this guy - http://www.pspatialaudio.com/LP_performance.htm Why measure and count when you can simply BELIEVE. And of course, you're probably forgetting all about the "new math" where 69 db of dynamic range is actually higher than 110, and 2% harmonic distortion is actually less than .02 %. Hey buddy....get with the program. Vinyl and tube amps are actually better than digital and solid state. Didn't you know? They cost a lot more too so there's your "proof".... : ) |
kosst_amojan @geoffkait Please, Geoff, enlighten the unwashed masses here as to what this "sufficiently advanced technology" is that appears to us as voodoo. Oh, I dunno, costco, but I suspect in your case it could be just about anything that looks at you a little cross-eyed. 🙄 Pop quiz. Multiple choice. Oh boy, oh boy! Which of the following are not woo? a. Green Pen b. Mpingo disc c. Silver Rainbow Foil d. Tice Clock e. Intelligent Chip f. Demagnetizing CDs |
