Veroman, I think there is much more to it than you say, such as ambience, note decay, sharp leading edge, human noises, timbre of instruments, but this is a senseless argument. I seldom buy seats that would give me the perspective that the mikes enjoy.
I don't live in a big city but used to attend meetings in Chicago and sought to buy returned seats in the center and front of Chicago's orchestral hall for the Chicago Symphony performances. I also heard many jazz singers performing there. My university has a very poor theater. The only good seats are in the front three rows. I've heard symphony performances, musicals, opera, jazz groups, and rock groups there. Frankly, my home system save for the visual perspective is better than those at the university.
My greatly improved music reproduction is largely based on vibration control, better grounding, ics and other cables, power cords and other ac conditioning, and digital sound source. |
Obviously this is a silly question but..... What kind of live music and in what setting? a symphony? dont even get me going. the reflected sounds and omni directional noise coming form the instruments is simply never going to be replicated that well. we listen to a representation of live music, not live music of course. We can sit in a concert hall and listen to the loudest mahler or wagner and never fatigue or feel strained . our biology knows real naturally produced sound when it hears it and there is no effort by the brain to correct it. some of these posts have said as much. other than that we are arguing over who has better mechanics. |
With the same speakers and electronics, I have heard great differences in realism with the same recordings. Of late I am hearing greatly more ambiance and note decay with double DSD versus 44.1 PCM on many different recordings. All this means, of course is that the filters have been moved upward to nearly 100k Hz. Also, I've heard the benefits of having linear power supplies rather than the cheap switching supplies so common in our electronics.
I have also heard greater realism using the Tripoint Troy with the new Thor SE grounding cables that keep RFI and EMI out of the signal. Subtleties in the music and background are revealed once the garbage is removed.
I've also heard the importance of what my components sit on. Two different technologies dominate the field, IMHO. Stillpoints converts vertical vibrations into heat and Star Sound takes the vibrations to ground rapidly with the use of a mix of brass and steel. I hear brass and high hat as well as drums sounding better with the Star Sound and more of a sense of ease with the Stillpoints.
Finally, there are magnets in cabling. High Fidelity Cables has shown me that the more the better using magnets. These cables have dramatically revealed realism for me that I once thought was impossible. Each and every version of these cables have increased the number of magnets used, the price, and the realism.
Would Iever go back to what I was listening to just three years ago? Not unless I was very curious as to how bad it was then. |
I think a Very Large Part of It (VLPoI) has to do with a Very Large Number of Things (VLNoT).
Impulse Response tells it all in an ideal amplifier. See "Linear Time Invariant Systems."
In a room, controlled dispersion is very important.
Then, there is my mood! Who can tell?
As for all of the Super Models and Prize Fighters, I've never had one in my lap, though my wife sure is real! |
I believe a Very Large Part Of It has to do with the Frontal Horizontal Directivity Measurements of the speakers! The better the measurements, the closer your get to... LIVE MUSIC IN YOUR HOME!! http://www.princeton.edu/3D3A/Directivity.html |
Regarding live sound, the hardest part to reproduce at home is the venue. No two venues are exactly the same, public or at home. So you are always working with that handicap. Otherwise, it is not so hard to get very lifelike sound out of recordings designed to sound that way.
Getting the exact perfect sound that you like all the time is not possible unless you are also making your own recordings.
Its like Hanna Davis and Kate Upton. Or ever see Ronda Rousey out on a photo shoot versus prepping for a fight? WHich is the most perfect? |
Regarding sound, at least the frequencies that humans can hear, anything is possible today with enough knowledge, focus and a budget. |
How close is a lap dance to the real thing?
Oops!
Honestly, lately I feel this is like pornography. Here we sit, bring it on! |
I know how a lot of you all feel about BOSE on this forum BUT I think the new and improved BOSE 901 series 6 mk2's gets you really close to the "real thing"...LIVE MUSIC!. |
That's a thoughtful reply.
Does the real thing have to be real?
What are the goals?
I think feeling the presence of live music is different, and being within it is even more so.
Do you ever sing in church? How does that feel? Is it live?
To me there is no percentage comparison. They are different things. Maybe that is what such a low 5% ranking is about from "The Violist." |
Mikewerner, while I agree, this doesn't mean that one cannot get closer. I have heard speakers that are very easy to listen to but which are not at all realistic sounding. |
Well, if you play a musical instrument vs. listen to sound, they are obviously very different things!
IMO nothing can aproach the connection you get to the music with playing - even listening in a concert hall. Any electronic copy and reproduction will always fall short. |
Vernneal, consider that at a concert imaging in the PA is not important. You may well be listening to mono.
Horns have no trouble doing imaging, that's for sure. There are other threads that have covered this subject.
Fas42, I agree completely about the power supplies. In fact I run a separate power supply with its own power transformer for the driver section of our amplifiers. The idea is to prevent any sort of noise that might occur in the output section from having any influence on the driver. This is one of the ways to really reduce IM distortion, as the power supply noise issues are usually modulation issues, but the effect is less pronounced for THD.
And I also agree that the engineering has to be right- you are absolutely correct that there are a ton of variables that affect any design and its easy for a problem in just one of those variables to completely overshadow other design parameters. IMO right here is where you encounter the human element in design.
Y'all have a nice holiday!! |
Look at a concert. Any concert. Chances are they have horn tweeters and midrange speakers and a big woofer in a speaker array. You get NO IMAGING. Stereo is a imaging experience that make one think he is in a studio not a hall,if you want a loud wall of sound get horn speakers. If you want the studio sound get non horn. |
Atmasphere, I am adamant that the rules of human hearing trump all other considerations Agree 100%. So the effect in an amplifier with loop feedback is that low level detail will be truncated and this is readily audible (IME) as a loss of ambient and soundstage information Unfortunately, disagree 100%. IF the feedback is done badly or is extremely minimal in its effect then that may be the result. I agree that "low level detail is truncated" is often the way distortion manifests, but my experience is that this is lousy power supplies and a myriad of other subtle mechanisms causing problems, which insufficient feedback may struggle to compensate for, but only ends up making things worse. In other words, the overall engineering of EVERYTHING has to be got right, and then that "harmonic noise floor" you speak of will be reduced to a level well below audibility Frank |
Fas42, on that page you will see a pattern diagram. I pointed this out as it is an example of a strange attractor.
Now what Chaos Theory has to say about this confirms what Crowhurst has pointed out in various places in his writings:
By the use of feedback in an amplifier there will be a harmonic noise floor (bifurcation) injected into the output of the amplifier. The amplifier will thus exhibit stable and chaotic behaviors.
The harmonic noise floor is inherently different from that of a noise floor composed of hiss. Our ears can hear about 20 db into the latter but none into the former. So the effect in an amplifier with loop feedback is that low level detail will be truncated and this is readily audible (IME) as a loss of ambient and soundstage information.
So its my opinion that you want the amplifier to behave in a way to more closely adhere to the rules of human hearing. I am adamant that the rules of human hearing trump all other considerations. In this case the masking rule of human hearing is where the problem is: we can't hear into that harmonic noise floor. Ridding the amplifier of negative feedback takes care of this and also rids you of the problem of making the slight amount of odd-ordered distortion that is part of that noise floor.
So you kill two birds with one stone, but you introduce another problem- how to get rid of lower-ordered harmonic distortion, which can also mask detail. The ear will hear this as a warmth, bloom or fatness in the lower registers and some people do find it annoying because the coloration can be obvious. BTW, this is something tubes are very prone to.
So IMO/IME, you have to do everything you can do eliminate distortion without feedback. That can be a bit of a trick and there is no one single design panacea for that. |
I am a VERY new member to the BAS and I am NOT speaking for them at all! I simply asked a couple of their members the same question that is being posed here for their opinion just as I asked my musician friend for his opinion.
Happy New Year Irv!
Ed |
Mr. Ayer-
I assume that you forgot all about listening to Holly Cole - "Don't Smoke In Bed" -on your system. I listened to the entire album but that was when your system was a year or two older so I guess that I haven't heard a "great recording on one of today's great systems" have I?
Furthermore, I'm not talking about a recording being acceptable if it "certainly resembled the sound of a piano", I'm talking about a recording being indistinguishable from the sound of a real piano.
We are nowhere near that today from everything that I have heard so far.
Ed |
Merry Christmas everyone, enjoy your families, see you back in the threads... Tim |
Well, Edseas2, I'm so glad that your view settles everything, after all! And of course, you have the BAS to back you up. And to think we've created a thread five pages long discussing a conclusion we could have just asked you for. :)
Merry Christmas, Ed. |
Fredseas2,
You banged the one note on my kids' upright piano and then compared it to a recording of a concert grand, as I remember. I agree with you that that one note did not sound identical to any one of the many notes in the recording. It wasn't even really close. But the recording certainly resembled the sound of a piano, and it wasn't a particularly good recording and it certainly was not one of the "best" systems available.
At this past RMAF I heard a live piano recital in the hotel lobby and then heard Ray Kimber's incredible four channel system play one of his IsoMic? recordings of a piano. Not identical, but boy were they similar to my ears. |
Atmasphere, The problem here is that while theorem is supposed, there are real-world phenomena that do not care about the theorem. I'm sorry, I don't quite follow. Yes, if you use Spice, say, to examine behaviour just based on straightforward theory, it will most certainly not match what really happens. However, if you add in ALL the actual parasitic behaviours of the components, the "real-world phenomena" you mention, into the Spice model then there should be very good agreement between the model (theory) and reality. After all, one of the classic nonsenses of a typical Spice circuit are the perfect voltage sources stuck where needed -- that alone guarantees that the match can be very poor. In volume three, page 26 Crowhurst ... Sorry, had a quick look, as far as I can see he is just saying, be careful with negative feedback, otherwise it becomes positive feedback and you have an oscillator -- straightforward stuff. Frank |
Actually, I don't remember anyone saying that an entire recording sounded real and, if so, based on my own experience (and it has been a few years ((as Mr. Ayer points out)) since I worked in the loudspeaker shop that made the loudspeakers for Bob Katz, after all) I have never heard any system EVER that comes CLOSE to making an entire recording sound real and, when I posed this same question to a few members at the last BAS meeting they were in agreement with me that they didn't think that it was possible to fool someone in to believing that an entire piece was real with today's technology.
As to playing 1 billion notes I simply took the conductor at his word without bothering to check his math.
Ed
Ed |
Actually, Ed, I don't think anyone said an occasional note sounded live, but only an occasional recording. Most of my recordings contain more than one note. ;)
FWIW, I don't think the Camilo sounds live on my system. Very nice, but not live. Too syrupy. Not enough edge. I think it's those Sennheiser mikes I bitched at Jack Renner about many years ago ('80s), when he started using them for Telarc classical recording. And they really don't work for Jazz, IMHO.
As for the one billion notes, well, maybe. Assuming 100 musicians playing 40 hours per week, all quarter notes :), for 20 years, that's about 1.1 billion notes or so. But that's 40 continuous hours per week, every second of every minute, of every hour. Maybe he rounded up. |
Here's a thought and why my friend, the trained concert violist, said that 5%, nay1% is MUCH too high a percentage:
From the posts that claim that the music sounded real (albeit from memory as I will not be rereading all of the posts!) I recall that the listeners who claimed that their systems sounded real always said that it was an occasional note that sounded real, never an entire piece.
If we simply ask, what number of NOTES soun(ed) real (remember, NO-ONE said that an entire piece, song, etc. sounded real) then we quickly realize that of ALL THE NOTES PLAYED that many fewer than 1% sound (ed) real.
At the Chopin concert which I attended the conductor said that in the 20 years that they'd been playing that he calculated that they played over ONE billion notes!
Just a thought.
Ed |
Sitting here listening, as I type this, to Michel Camilo's Solo album (Telarc Jazz) at something like a realistic volume level... if this is 5% of live, I'll take it as-is and be happy for a long while. |
Phaelon,
I agree with you that the thread is going in an interesting direction. KIrkus and others have broadened my understanding of the topic tremendously. It was not my intent to peg a specific percentage to the question of how close are we to the real thing beyond that I think 5% is too low in the context of today's very "best" systems.
Has Edseas heard a really great recording on one of today's great systems? He told me he hadn't. Can we agree that we are at least getting closer to the real thing? From reading many of the posts, I think the answer for many of us is YES. Sorry for your head, Mapman. |
In his recent work (unpublished so far) he has shown that if music is delivered intact to the brain, it is processed in the limbic system. He has also shown that as a stereo system violates human perceptual rules, the processing is moved to the cerebral cortex."
If I understand you correctly, this validates my rationalization that their is no rationalizing music. I have no idea why I find music pleasurable or why, when a chord is played on a musical instrument, it seems to strike a corresponding cord in me. When that happens, it has nothing to do with my cerebral cortex. But the cerebral cortex is precisely what many of us rely on when we listen to our systems and try to validate our decisions. |
The problem here is there is little that is convenient that will quantify the subjective experience. However, that is not to say that the subjective experience *cannot* be quantified, it can and has by Dr. Herbert Melcher. In his recent work (unpublished so far) he has shown that if music is delivered intact to the brain, it is processed in the limbic system. He has also shown that as a stereo system violates human perceptual rules, the processing is moved to the cerebral cortex. So while we can argue about what works and what does not, our brain is working it out anyway, whether we like it or not. Kirkus, your 'quote' of me was not verbatim and thus the meaning and demeanor was altered. It's my impression from many of your past postings that there are a handful of conceptual errors in your understanding of the traditional application of negative feedback and its Nyquist stability criteria . . . to the point that a discussion of the associated theory and measurement performance is moot. Yes, I imagine when one has a different viewpoint, it is convenient to use such an argument. I *am* familiar with Fourier, Shannon and Nyquist, FWIW. However I see a lot of their 'relevant' theorem as being misapplied in audio. The problem here is that while theorem is supposed, there are real-world phenomena that do not care about the theorem. When you realize that the real world isn't going to go away, often it is more pragmatic to observe it and accept that it exists. Now I would exhort you to take a look at Chaos Theory as well, http://en.wikipedia.org/wiki/Chaos_theoryand having done that read Norman Crowhurst's book on negative feedback and amplifiers, called Basic Audio. You can download volume 3 as a pdf from http://www.pmillett.com/tubebooks/technical_books_online.htmIn volume three, page 26 Crowhurst graphed the behavior of an amplifier with feedback (Nyquist diagram) that years later Choas Theory identifies as a 'strange attractor' (strange attractors are used to predict the behavior of a chaotic system). You will also see that the formula for feedback and chaotic systems are pretty much the same thing. But I (very respectfully) remain curious as to whether or not you've ever had an auditory experience that pegs the needle on your own personal, internal "sonic truthiness" scale? And has it ever been delivered by equipment that has a design approach that's incongruous with your own? (Please note that the phrase "pegs the needle" is an important one, meaning that at the time of the experience, an experience closer to the truth cannot be imagined and/or is simply irrelevant). Of course, and I mentioned exactly this rather early on. So I am one who maintains that we are closer to 90% than 5%, insofar as microphones, headphones and simple audio electronics (no power amps or speakers) are concerned. I made the point at that time that the recording/playback media is arguably the biggest failing. I have had multiple experiences like this in the studio, and I have had a few like this at home with my stereo (but they don't qualify due to your criteria). My comment about the ramifications of that has already been posted and misquoted. |
"Progress ad Infinitum", "Karl Popper" & "verisimilitude", "Copernicus"
That's what I was trying to say Kirkus, or at least it would have been if I was smart enough.
IMO, this has become a very worthwhile thread to the extent that it has veered away from it's original and more casual, percentage of realness inquiry, into something more significant which is an examination of perceived reality and audio. |
An analogy (yet again!): if you drank red wine which was always very ordinary or even mediocre, you would or could with great conviction claim that there is no such as a truly extraordinary, supremely satisfying great red. But, if you sampled such a wine even just once only, and then returned forever more to the much lesser variety, you would always retain the memory of the experience, and know what was achievable. All obvious enough; and to me this experience or lack of such experience is at least one thing that divides people in this field of audio.
This clearly puts me on David's side, in believing in AND knowing what is possible. If you can put on the worst, I repeat, the worst recording in your collection and still be able to say it "sounds convincingly authentic to the live source" and talk of "The delight it gives me, however, comes from listening into the music" then you've arrived. The fact that this goal is not achievable by pushing some "perfectly" engineered, platinum plated button at the moment is just part of the landscape ...
Frank |
My head is going to burst..... |
Maybe we... someone... anyone can come up with a chart and modifiy it until there is a concensus...
I agree that it is near impossible to make a system sound truly "live", but I still say 5% is rediculously low.
Edison's 1st phono may be 5%, but What is
Tonal Accuacy worth?
What is a soundstage worth? and as the sound stage improves, does the value go up?
What is timber worth? P.R.A.T?
Do dynamics increase your score?
When an uneducated(audiophile or musician wise) person sits in front of your system and their jaw drops.... Would that happen at 5%? I think not.... Actually a verifiable rating system would be something that we would all love to have.
Wouldn't you like to hear a 93 vs a 27? |
5%, fwiw, is seemingly extraordinarily generous - at least to the ears of a trained violist and, at least according to him.
In a later part of the same conversation I asked him if he thought that it were possible to reproduce "even 5%" of the musical reality of a live unamplified performance based on what he heard from the conductor's system.
His simple response was "No, not even close to 5% - much less than 1%."
But, then again, he doesn't have CDK84's incredibly in-depth knowledge of today's stereo systems - he's just a trained concert violist so he must not know much, after all.
:)
Ed |
Are we getting somewhere?
Pubul57 states that "the "gap" is small", so I feel secure, now, in inferring that we're likely well beyond Edseas2's and other nay-sayers' 5%.
Let's look at it without prejudice: on an absolute scale, 5 of 100 per cent would produce a recording of a piano that sounded like Linus' toy instrument. We have far better playback than that today and have for many years.
The indisputable fact that we have no way to measure the more far-reaching and seemingly esoteric or obscure aspects of our marvelous minds' response capability does not reduce the joy of listening --or the pleasure of a fine and pointed discourse, for that matter.
'Progress', as Kirkus and Atmasphere describe it, *is* happening, whether Edseas or his violist friend accept it. We're beyond 5%, like it or don't.
Luddites were against technology on a religious basis: in philosophy there is no religion, nor is there, directly, religion in scientific reasoning (at least at our present level of understanding; there may be marvel or regard, but that is different: vis Hocking's "Into the Universe").
Edsea2's objection to the 5% solution appears unscientific, and though some of the more esoteric tweaks in our endeavor appear to revolve around witchcraft, I don't care: if my listening experienced is enhanced toward my goal of playback sounding more like live music, I don't care what kind of "weird sh*t" goes into, is placed upon, or comes out of my transducers.
If you can't quantify it, but it works with concensus or others' verification, that simply means our science lags behind our listening pleasure in the ability to measure what sounds convincingly authentic to the live source.
Is that a bad state of affairs? Not knowing why something works?
I submit that having something work --well beyond 5% efficacy-- is cause for celebration. I'm grateful for the pleasure and solace, not to mention the mood-changing opportunity that my music system offers me.
I've thought about it, been frustrated by it, and exhilarated as I learned to 'tune' it to [something approaching] its potential. I enjoy learning, talking and writing about it. The delight it gives me, however, comes from listening into the music, and out of myself.
Best Wishes for Festivus, whichever flavor you prefer. May there be satisfaction in your listening, and joy in your heart.
David
|
I try to keep in mind that with recordings, the recording itself and how it was produced is the real thing that matters.
Remember recordings are reproductions. They can approach the real thing but probably never completely equal it. I've heard some come close enough, at least in my listening environment, that I do not care.
Most often, recordings are abstract reproductions conceived by its creators that bear little resemblance to the real thing, assuming it is even possible to ever experience that. |
Yup, not even 1000 Class A watts with zero NF is going to do that - "close" in so many ways, but it never really sounds like the real thing - even if the "gap" is small, it is unpassable for whatever reasons from recordings thru source thru electronics thru speakers to the way we hear. Which does not mean our equipment and recordings are not tremendously enjoyable in spite of that, or worth persuing with a spirit of fun. |
My friend, a viola player ("violist") recently tried out for the "Marine Chamber Orchestra" (also known as "the President's own") so I asked him if he had ever heard a high end audio system. He said he once went to the home of a conductor who had a stereo system that "took up the whole wall" - (clearly fitting the description of the impoverished musician who is unable to afford high end audio!).
I asked him how it sounded and he said "Great!".
I then asked him if it sounded "real" and he looked puzzled and wanted to know what I meant by that. I responded that I wanted to know if it sounded like a live performance (knowing that he plays live, unamplified music in an orchestra) and he looked at me smiling and said:
"Are you kidding? Of course not! It can't, its not possible to reproduce those sounds and the sense around you."
Ed |
Atmasphere, maybe I did miss your point, but I did re-read your post . . . and I think my quote was verbatim. But the logical problem remains -- I'll see if I can't address it first via Mapman's quote: Human ears (and brains)are complex sensors and information processors of an order far exceeding science or technologies ability to model exactly.
Given this truth, any hypothesis regarding being able to accurately predict the outcome of an individual's listening experience based on science alone, even in a properly executed scientific experiment or series or experiments, has to come into question. This argument is closely akin to Progress ad Infinitum, one of the tropes of skepticism as outlined by Roman philosophers (Sextus Empericus?) in the first century A.D. . . . that is, anything that can be regarded as proof must in and of itself be proved, on and on to infinity. So under this line of thinking, knowledge in and of itself cannot advance or become closer to the truth . . . leading to the trope of Assumption, that all scientific knowledge is merely theory and not truth. But our entire craft of audio is among countless obvious artifacts that indicate that our knowledge of the physical world is indeed expanding and becoming more precise, thus closer to the truth. Karl Popper dealt extensively with the logical basis for this through his concept of "verisimilitude", or the extent to which a scientific theory resembules the truth. It is through this concept that we can look at the evolution of ideas from Copernicus, to Galileo, and to Newton . . . with today's knowledge that all their views of the physical world were false. But each of them was able to formulate ideas with greater verisimilitude, building on the work of those that preceeded them. And for the original topic of this thread, I think it's indeed undeniable that our ideas about the understanding of sound perception and reproduction have greatly increased in verisimilitude, and gotten us closer to the truth . . . especially when viewed over the span of the last 150 years or so. It is on this basis that I fundamentally disagree with the popular audiophiles' notion that Mapman articulated. We can indeed use science to predict the outcome of an individual's listening experience, even though the extent to which we can is still significantly inconsistent and variable. But we are continuously improving our ability to do so, as the logical result of our scientific theories ever evolving toward increasing verisimilitude. My point to Atmasphere is this: as people involved in the design and manufacture of artisan audio equipment, we are of course required to evaluate the "truthiness" (Stephen Colbert's word) of the performance of our own, and others', equipment. And we then use such an asessment to determine the verisimilitude of our theoretical ideas. It's my impression from many of your past postings that there are a handful of conceptual errors in your understanding of the traditional application of negative feedback and its Nyquist stability criteria . . . to the point that a discussion of the associated theory and measurement performance is moot. But I (very respectfully) remain curious as to whether or not you've ever had an auditory experience that pegs the needle on your own personal, internal "sonic truthiness" scale? And has it ever been delivered by equipment that has a design approach that's incongruous with your own? (Please note that the phrase "pegs the needle" is an important one, meaning that at the time of the experience, an experience closer to the truth cannot be imagined and/or is simply irrelevant). |
Kirkus, I think you missed my point! The quote you put up is edited and not what I said. Try re-reading my post, without the idea that I am trying to make you wrong- that was not my intent at all.
Irv, maybe you were joking but Sound Labs have anything but a flat impedance curve. Just because a speaker has a variable impedance curve does not mean that an amplifier with a high output impedance cannot drive it well, without tonal anomalies. It is all in the intention of the designer, as the article that Al linked points out.
A vital point here is that distortion in amplifiers and speakers is perceived by the ear as a tonality, and without this understanding that tonality won't get measured. This is close to the heart of the subjectivist/objectivist debate. Once you understand how the ear/brain perceives things, a lot of this debate goes away. |
Irv raises a good point about the interaction of high amplifier output impedance with speaker impedance vs. frequency variation. An OTL amp having a 4 ohm or other comparably high output impedance will not be a suitable match for some speakers. See Ralph's Competing Paradigms paper for additional discussion of this subject. Regards, -- Al |
Irvrobinson, how does that 4ohm+ output impedance affect interaction with the loudspeakers As Atmasphere states, provided that the output impedance is purely resistive in nature, that is, it does not behave like a capacitor or coil to any degree over the frequency range mentioned, then its effect will be totally benign. Even if it were ridiculously high, say 100ohms, same applies. All the latter would mean is that the speaker would never get very loud! I also agree with Atmasphere regarding "decrease the propagation delay of the circuit", this is exactly what needs to be done to allow any feedback to do its job. Some people may not be aware that several highly regarded SS amps consisted of nothing more than an output stage driven by a high quality opamp, with, by normal standards, extremely high levels of GFB. "objectivist's" belief system usually can't include a reality outside simple regurgations of common-practice electrical analysis found in an average undergraduate EE textbook, and the "subjectivist's" belief system is so fundamentally undisciplined as to be able to include some really silly, wacky sh*t. Human ears (and brains)are complex sensors and information processors of an order far exceeding science or technologies ability to model exactly. Agree 100% with both of the above Frank |
Human ears (and brains)are complex sensors and information processors of an order far exceeding science or technologies ability to model exactly.
Given this truth, any hypothesis regarding being able to accurately predict the outcome of an individual's listening experience based on science alone, even in a properly executed scientific experiment or series or experiments, has to come into question. |
"Irvrobinson, while our amplifiers tend to have higher output impedances, that impedance curve is nearly identical to the frequency response curve of the amplifier, IOW linear from 2Hz-100KHz."
And how does that 4ohm+ output impedance affect interaction with the loudspeakers, since loudspeakers do not usually have anything like linear impedance curves? Won't this effect the system frequency repsonse? Or are you assuming very high impedance speakers with very smooth impedance curves, like Soundlabs? |
The system was entirely solid state. The format was a digital reel to reel, 1/2" wide. I really did not hear the system, it was only the experience of the music. So what would it have been like if it was 2" analog with my amps on each speaker? Hey, maybe it would have been better. Atmasphere, I'll admit I don't quite know what to make of this. Although I respect that you have sufficient confidence in your design approach that you feel your products could ALWAYS make a subjective improvement over anything else, it seems that your judgement (or at least your recollection) of this particular experience is totally dependent on your knowledge of the technical matters of its presentation. This is what I would call a "Maggie Blackamoor" conclusion, after the character on Little Britain: http://www.youtube.com/watch?v=hUpHDtpoY9wBut since I brought up the subject of scientific philisophy (and also to avoid at least a bit of the well-trampled "NFB argument" road). . . to be a bit more precise this would thought of as a plainly "coherentist" argument. That is, the truth or validity of a given conclusion is based upon how coherent it is with an existing perspective or set of beliefs. For the coherentist, the method by which a theory is refined (made more precise) is when data is presented that incoherent with the current belief system, the belief system is revised to restore coherence with new data. But the logical problem is obvious, it's the same with all theories of justification: it fundamentally relies on one's intellectual "concience" to formulate ideas that evolve beyond one's own belief system. In the field of audio this is particularly problematic, becuause our understanding of many of the perceptual and psychological mechanisms lags far beyond our practical understanding of the physical science on which our technology is based . . . technology that we so routinely use to (attempt to) fool these perceptual and psychological mechanisms. But we can also see from this line of reasoning that the traditional audio "objectivist" arguments have NO better grounds in modern scientific practice than the "subjectivist" . . . they are both in actuality simply "justificationist". It's simply that "objectivist's" belief system usually can't include a reality outside simple regurgations of common-practice electrical analysis found in an average undergraduate EE textbook, and the "subjectivist's" belief system is so fundamentally undisciplined as to be able to include some really silly, wacky sh*t. |
Hi Frank, opamps usually have much lower propagation delays than power amps do! So feedback is more effective with them.
To improve the effect of feedback and decrease the resulting odd ordered harmonic generation, decrease the propagation delay of the circuit.
Irvrobinson, while our amplifiers tend to have higher output impedances, that impedance curve is nearly identical to the frequency response curve of the amplifier, IOW linear from 2Hz-100KHz. |
Sorry Weseixas, re ".. can follow along ...". My earlier comment was just firstly agreeing with Kirkus that a lot of people have had special listening moments without it quite making sense why, and secondly, that my answer is to be fussy, fussy, fussy, just like people who make and look after aircraft are, which is why flying is so relatively safe, ie. equivalent to audio sounding "real".
Frank |
Frank ,
The time smearing can be significant, this is what Atmasphere was alluding to, I do believe this is so if one get's carried away with NFB. Most SS designers today understand such and dont drink from the NFB pond in excess. The only way to eliminate it's usage is to design amplifiers which are very stable( matching transistors goes along way here) I do Believe Nelson Pass has made an even bigger step and acquired some pretty interesting devices, so we will see.
Tube amplifiers also use less NFB than there SS counterparts, so if NFB is really,really, bad then.....:):)
IMO output stage Bias is also very important in creating "that sound" associated with SS amps, how you balance the 2 ( Bias amt/NFB) when attempting to reduce distortion gives the amp that certain SS "character".
Regards, |
Atmasphere, unfortunately the way you present the concept of feedback with the term "propagation delay" helps to 'propagate' (sorry, couldn't help it ... :-) ) a misconception about negative feedback. Yes, "negative feedback is always lagging behind" but it is still able to "correct the signal it was supposed to". If it ends up lagging by 180 degrees, half a wavelength, with gain still happening, then you have positive feedback, and an oscillator, and fried tweeters!
So, the feedback ALWAYS lags, even by some tiny amount, but that is just part of the understood design of any working circuit. You can easily buy one of those "terrible" opamps with much more global feedback then a typical audio power amp, that is working comfortably at microwave frequencies, that is, beyond 1,000,000 kHz -- not bad for such a "mediocre" part!
Global feedback in an audio device, on the other hand, with discrete components is typically rolled off (because it has to be for stability, remember the oscillator!) to become non-existent at the higher frequencies, where it is most necessary, and where the ear is most sensitive to distortion -- that is part of the real problem. Also, that is why nearly all gear has rising distortion at higher power, and higher frequencies; in other words, it is not the presence of feedback that's the problem but that at the very time it is most needed, it's done a bunk ... :-) !!
Frank |
Mapman says:
"Well, the whole negative feedback issue has been beaten to death pretty thoroughly already in other threads.
My conclusion is that it is just one of many design and execution factors that affect results depending on how well it is executed."
I couldn't agree more. |
