Introspection and hyperbole control

[853guy]

You said, in the post above, that I had missed the point, but now you seem to be making it again.

Nope, sure didn't...

You miss the point, Tim - system thinking & relevant measurement techniques are required is the point.

You appear to be saying that there is not a meaningful relationship between the measurements engineers use to asses, develop and refine their products, and the impact that the data has on a component's performance when playing a recording through a system. Did I get that right?

No, my argument has nothing to do with any specific engineer and their respective testing methodology (which from what little I know regarding certain specific engineers, can be wildly divergent across the spectrum of objective and subjective).

My argument is based on your statement here:

I believe electronics should be as true to the recording as possible...

If that is the case, could you please tell me how you ascertain the veracity of your system's "true-ness" to the recording without directly comparing the musical waveform inherent in the recording medium with that same musical waveform perceived by you at the speaker/room interface?

If that's not the case, and what you actually believe is that "electronics should be as true to the steady-state test signals used to produce their measurements as possible...", then could you please tell me what you believe the meaningful relationship to be between said signals and the dynamic and continuously modulating signals of a recording containing music?

 

[Phelonious Ponk]

Nope, sure didn't...



No, my argument has nothing to do with any specific engineer and their respective testing methodology (which from what little I know regarding certain specific engineers, can be wildly divergent across the spectrum of objective and subjective).

My argument is based on your statement here:



If that is the case, could you please tell me how you ascertain the veracity of your system's "true-ness" to the recording without directly comparing the musical waveform inherent in the recording medium with that same musical waveform perceived by you at the speaker/room interface?

If that's not the case, and what you actually believe is that "electronics should be as true to the steady-state test signals used to produce their measurements as possible...", then could you please tell me what you believe the meaningful relationship to be between said signals and the dynamic and continuously modulating signals of a recording containing music?

We are going in circles. Yes, I believe measurements are the best way to determine the accuracy of components and systems, and I believe I said that. And I thought you said that you don't believe the measurements being used by audio engineers (sine waves) are effective in predicting the performance of those components when playing music. I'm sorry if I misunderstood you. That's not what you were saying?

Tim

 

[853guy]

We are going in circles. Yes, I believe measurements are the best way to determine the accuracy of components and systems, and I believe I said that.

Tim, in this thread alone, you’ve continued to assert an iteration of the same phrase:

“The goal of an audio system is fidelity to the recording,” post #79, “I believe electronics should be as true to the recording as possible,” post #95.

Having historically read and responded to a number of your posts on this and other threads, I believe the following sentence “Our systems should be faithfull/true/accurate to the recording - no more, no less,” could be considered representative of your current beliefs, yes?

Given that, and to return to the quote above -

“I believe measurements are the best way to determine the accuracy of components and systems”

- let me ask again:

How do you, Tim aka Phelonious Ponk (not an engineer, not a component designer, nor anyone else) determine the veracity of your system’s ability to be faithful/true/accurate to the recording as formatted (easily analysed as a unique waveform with associated spectra) unless you’re comparing that recording’s waveform as formatted with the exact same recording’s waveform produced at the room/speaker interface?

Or, if it makes it easier to answer: If you’re not comparing waveform with waveform through measurement (which you believe to be “the best way to determine the accuracy of components and systems”) then how are you determining the fidelity/accuracy/trueness of your system when playing back recordings?

If you don’t want to answer the question, fine. I just would have thought that someone who clings tightly to a very particular definitive position would be more willing to explain their process without deflection or equivocation.

And I thought you said that you don't believe the measurements being used by audio engineers (sine waves) are effective in predicting the performance of those components when playing music. I'm sorry if I misunderstood you. That's not what you were saying?

Come on, Tim - I haven’t mentioned audio engineers, specifically or generally - you brought them into the discussion.

And I’ve been fairly clear on what my beliefs are in posts #37, #41, #44, #96, #99, and #105 - I’m questioning your belief system. You’re the one who continues to state “fidelity to the recording” is the ultimate goal of an audio system, and I have continued to ask by what process you ascertain this.

If you wish to continue with the above line of thinking, then I think it’s fair (and logical) that we compare apples with apples (the recording as formatted with the recording at the room/speaker interface) in order for the process to be considered consistent and meaningful, rather than introduce coconuts or other drupes into the argument (steady-state signals) that do not represent the complexity of real music constantly modulating over time. Again, if you believe an audio system should be accurate to the test signals it’s fed (though you continue to state it should be accurate to the recording) then great - we compare drupe with drupe. If however, you think steady-state signals are representative of real music, then I’d be very keen to know how you consider them to be so.

For clarification: tomelex posted this:

Other than the modulations caused to electronic devices by changing currents (which in most feedback designs is taken care of by feedback) feel free to enter that thread and let us know what a sinewave does not exercise in an electronic part of the amplification system. I would sure like to know

I responded by posting what real music looks like as a waveform and its spectral content relative to a steady-state signal and asked:

Which of the two above would you say would produce a more-linear result?

He referred me to another thread, and has since revised his original post.

 

[Ron Resnick]

853guy,

I am enjoying your posts, and I appreciate your effort to be analytically consistent!

 

[Phelonious Ponk]

How do you, Tim aka Phelonious Ponk (not an engineer, not a component designer, nor anyone else) determine the veracity of your system’s ability to be faithful/true/accurate to the recording as formatted (easily analysed as a unique waveform with associated spectra) unless you’re comparing that recording’s waveform as formatted with the exact same recording’s waveform produced at the room/speaker interface?

Or, if it makes it easier to answer: If you’re not comparing waveform with waveform through measurement (which you believe to be “the best way to determine the accuracy of components and systems”) then how are you determining the fidelity/accuracy/trueness of your system when playing back recordings?

I don't mind answering. Here you go -- I don't. I've been past that for years. Now I'm just enjoying the music. I assessed the accuracy of my equipment when I was shopping for it, by understanding the goals and design philosophy of the manufacturer, and by reading all the measurements I could get my hands on. Then I listened. One thing I listen for, other than simple enjoyment, is how well a system reveals the differences between recordings. I compare what I hear to other systems and to my headphones (I have 3 that all sound quite different). I figure that the less a system seems to impose its own sound on recordings, the more it reveals the individual character of recordings, the more likely it is that it is reproducing the recording more accurately, the less likely it is to be coloring the recordings with a sound of its own.

Is this my own subjective view of "accuracy?" I think that's the point you're trying to make. Maybe. Now let me ask you a question. If the "accuracy" of an audio component is not "high fidelity," if it's not the ability of that component to put out the signal it receives with the least amount of distortion of that signal possible, what is it?

Tim

 

[DaveC]

And this is what Diapson was getting at - you have no objective judgement of accuracy that you use - you do it like everyone else does & decide which sound you "think" is more accurate, which sound you prefer. You don't really know whether you are listening to a "pleasant distortion" or not.

To quote diapson "What do you say to other people who can't find subjective accuracy in equipment that measured well?"

I'm a few pages behind but had to remark on this, as it is absolutely true.

What some consider accurate and detailed may be distortion. There are artifacts produced by poor quality parts that may add to a sense of detail and accuracy. Like warmth, it adds these artifacts to everything and eventually they get tiring but at first they can sound better. Like Groucho's Mona Lisa post...

One example is accentuated leading edges which can be caused by lower purity silver wire. It sounds exciting at first but soon causes listening fatigue. Another is a small amount of grain. When I was developing my own wire for my cables I tested a stranded wire vs a solid-core wire at one point, the stranded wire produced a tiny bit of grain that seemed to "add detail" to a female vocal track we were listening to, at first we were impressed. But after changing back to the solid-core wire this grain went away and it became obvious what was happening. The stranded wire introduced some grain because of the nature of stranded wire while the solid-core wire did not.

 

[Phelonious Ponk]

So we like what we like, regardless of how accurately it performs in tests. That didn't need 12 pages.

Tim

 

[DaveC]

So we like what we like, regardless of how accurately it performs in tests. That didn't need 12 pages.

Tim

What's interesting about this to me is that appreciation for music reproduction has two distinct groupings with very few in the middle...

1. The pursuit of high fidelity: self explanatory, these audiophiles want to hear as much detail and as accurate of a reproduction as possible. As discussed sometimes it's possible to get "fooled" and think distortion is accuracy but with enough experience we recognize distortion for what it is and constantly seek to eliminate it. Higher fidelity and increased resolution lead to better emotional connection with the music.

2. Those who want something warmer and with a rolled-off top end compared to true high fidelity. True accuracy makes their ears bleed and they seek a compromise of warmth to resolution for their personal tastes. If they own accurate speakers they will choose warm, romantic sounding gear to compliment them. Having the best resolution possible does not top their priority list, while it is often recognized and appreciated, the priority is something that sounds "musical" according to their personal tastes. A warm sound with a rolled off top end allow them to connect with the music without getting irritated by a perception of too much high frequency energy or harshness.

I make cables for both groups of people, mostly for the pursuit of the traditional definition of "high fidelity", but I have a couple of cables that are made for folks in the 2nd group. IME there is a distinct difference between these folks with almost nobody in the middle. Sometimes folks in group 2 get converted to group 1 by hearing a non-fatiguing high fidelity system. Often, folks in group 2 own speakers that use compression drivers and are seeking to mask the naturally harsh sound they provide.

 

[853guy]

I don't mind answering. Here you go -- I don't. I've been past that for years. Now I'm just enjoying the music. I assessed the accuracy of my equipment when I was shopping for it, by understanding the goals and design philosophy of the manufacturer, and by reading all the measurements I could get my hands on. Then I listened. One thing I listen for, other than simple enjoyment, is how well a system reveals the differences between recordings. I compare what I hear to other systems and to my headphones (I have 3 that all sound quite different). I figure that the less a system seems to impose its own sound on recordings, the more it reveals the individual character of recordings, the more likely it is that it is reproducing the recording more accurately, the less likely it is to be coloring the recordings with a sound of its own.

Is this my own subjective view of "accuracy?" I think that's the point you're trying to make. Maybe.

Well, I think we probably can't come to any other conclusion except that, yes, the process is tantamount to a subjective analysis based on some objective criteria. It’s hardly robust, but is simple enjoyment as a determining factor required to be?

Now let me ask you a question. If the "accuracy" of an audio component is not "high fidelity," if it's not the ability of that component to put out the signal it receives with the least amount of distortion of that signal possible, what is it?

Are you asking “what is 'high-fidelity' if it is not a measure of an audio component’s linearity when fed test signals”, or are you asking “what is 'high-fidelity' if it is not a measure of an audio component’s linearity when fed music signals”?

 

[Diapason]

DaveC, that does indeed seem to be the standard narrative, and I get the sense that anytime anyone says they're looking for a "warmer" sound (something I've said myself) the general assumption is that this translates to "coloured". But I don't understand why this should be so, and it's related to questions I've asked here before. I don't find live music harsh, or at least not in the way I find some supposedly accurate speakers harsh. In fact, if I'm looking for warmth, I'm looking for the same natural warmth I hear in a concert hall (for example) that I frequently don't find in hifi systems. From the numbers of people preferring tubes over superior-measuring SS, or indeed vinyl over superior-measure digital, there are obviously plenty of people who fall into this category, but I'm not convinced all or indeed many are looking for a "coloured" sound. They're looking for a sound that, to them, sounds like music. I called this "subjective accuracy" above, and whether we like that term or not, I think it explains the concept: I want music to sound subjectively like it does when I hear it live. If a system is lacking that warmth that I hear in real life, then subjectively that's not "accurate" to me.

So what's going on here? It may be the case that there are a huge number of "harsh" recordings out there, and so the warts and all system is just showing (accurately) what's on the disc or the tape or in the file. For a long time I accepted that as a reasonable answer to the harshness/fatiguing sound problem, but over time it makes less sense to me. If harshness or fatiguing sound or similar nasties are built into SO MANY recordings, then the high fidelity question starts to go in another direction. If we reach the point where a huge number of CDs that I want to listen to don't sound good on a supposedly accurate system, then accuracy in this sense is no use to me.

Anyway, that's a separate issue in a way, but back to my original point: why should "accurate" in audio circles so often be taken to mean "fatiguing"?

 

[Diapason]

In a concert hall , depending upon your seat, you could be listening to mostly reflected sound, very different from your living room.

So you're saying an accurate system at home won't help anyway. Okay.

Warm doesn't mean anything,

Ah Keith, you and I both know that OF COURSE it means something. It may not be a well-defined concept, it's obviously not a scientifically-defined term, but none of that says it's without meaning. We're not in the science forum here, and music fans the world over know the difference between words like "thin", "harsh", "fatiguing" on the one hand and "warm" on the other hand. It's not my job to translate this into a science term, I'm merely reporting what I hear. FWIW, I absolutely don't believe that warm always coincides with rolled-off treble, but that might be one way to get there.

Let's take away the concert hall, if I listen to any instrument under any circumstances, it has a body to the sound, a warmth if you will, that's often lost in reproduction. I'm not alone in feeling this, as is obvious from discussions here, there and everywhere. If we want to move forward, it's pointless to pretend that audiophiles can't describe any sonic findings unless they speak the language of science. I'm telling you my subjective impressions, and I think those impressions are shared by others. That's all.

 

[PeterA]

What's interesting about this to me is that appreciation for music reproduction has two distinct groupings with very few in the middle...

1. The pursuit of high fidelity: self explanatory, these audiophiles want to hear as much detail and as accurate of a reproduction as possible. As discussed sometimes it's possible to get "fooled" and think distortion is accuracy but with enough experience we recognize distortion for what it is and constantly seek to eliminate it. Higher fidelity and increased resolution lead to better emotional connection with the music.

2. Those who want something warmer and with a rolled-off top end compared to true high fidelity. True accuracy makes their ears bleed and they seek a compromise of warmth to resolution for their personal tastes. If they own accurate speakers they will choose warm, romantic sounding gear to compliment them. Having the best resolution possible does not top their priority list, while it is often recognized and appreciated, the priority is something that sounds "musical" according to their personal tastes. A warm sound with a rolled off top end allow them to connect with the music without getting irritated by a perception of too much high frequency energy or harshness.

I make cables for both groups of people, mostly for the pursuit of the traditional definition of "high fidelity", but I have a couple of cables that are made for folks in the 2nd group. IME there is a distinct difference between these folks with almost nobody in the middle. Sometimes folks in group 2 get converted to group 1 by hearing a non-fatiguing high fidelity system. Often, folks in group 2 own speakers that use compression drivers and are seeking to mask the naturally harsh sound they provide.

I actually think of myself as sort of in the middle. I like accurate to the recording, and without distortion or listening fatigue. I also want it to sound natural and convincing with no obvious rolling off of any frequency. I use live acoustic music as my reference. I think most of my local audio buddies feel the same way.

I feel analog LPs sound more accurate and natural at the same time. Most of my friends do to. I don't know what that means for cable technology.

 

[DaveC]

DaveC, that does indeed seem to be the standard narrative, and I get the sense that anytime anyone says they're looking for a "warmer" sound (something I've said myself) the general assumption is that this translates to "coloured". But I don't understand why this should be so, and it's related to questions I've asked here before. I don't find live music harsh, or at least not in the way I find some supposedly accurate speakers harsh. In fact, if I'm looking for warmth, I'm looking for the same natural warmth I hear in a concert hall (for example) that I frequently don't find in hifi systems. From the numbers of people preferring tubes over superior-measuring SS, or indeed vinyl over superior-measure digital, there are obviously plenty of people who fall into this category, but I'm not convinced all or indeed many are looking for a "coloured" sound. They're looking for a sound that, to them, sounds like music. I called this "subjective accuracy" above, and whether we like that term or not, I think it explains the concept: I want music to sound subjectively like it does when I hear it live. If a system is lacking that warmth that I hear in real life, then subjectively that's not "accurate" to me.

So what's going on here? It may be the case that there are a huge number of "harsh" recordings out there, and so the warts and all system is just showing (accurately) what's on the disc or the tape or in the file. For a long time I accepted that as a reasonable answer to the harshness/fatiguing sound problem, but over time it makes less sense to me. If harshness or fatiguing sound or similar nasties are built into SO MANY recordings, then the high fidelity question starts to go in another direction. If we reach the point where a huge number of CDs that I want to listen to don't sound good on a supposedly accurate system, then accuracy in this sense is no use to me.

Anyway, that's a separate issue in a way, but back to my original point: why should "accurate" in audio circles so often be taken to mean "fatiguing"?

Well, there are issues with distortions that cause fatigue and often they are more noticeable in systems that are "high fidelity" vs systems that are voiced warm/rolled off. SO it may not be the accuracy you are responding to but other undesirable distortions that are not warmth, but harshness, glare, accentuated leading edges, etc. It is possible to have a very resolving and "high fidelity" system that is not harsh and fatiguing. It's just not easy to accomplish and many have never heard such a system because most consumer gear contains parts that add these distortions. Brass and bronze connectors add undesirable grain and glare, many speakers use steel quick disconnects at the speaker drivers, these sound horrible, and the list goes on.

I build my own tube gear because I get the best results that way, tubes are more linear and I can linearize a tube by using the right plate load, and I don't need to use negative feedback. In an case the tube/SS dichotomy is BS and has nothing to do with anything. Implementation of the technology and circuit design is far more important.

One of my definitions of accuracy is accuracy of tone or timbre. This facet of reproduction can lean either warm or cool, and cool isn't any more accurate than warm. People seem to think the coldest, most analytical presentation is the most high fidelity and this is simply not the case. Harsh and thin sounding tone is no more high fidelity than warm, bloated tone. This is why UPOCC silver wouldn't do for my cables. It was not until I added a certain amount of gold as an alloying element that I was satisfied with neutrality of tone. Copper always adds warmth and has a corresponding reduction in resolution, UPOCC copper is far better than regular drawn copper wire though. UPOCC silver has far better resolution and does not accentuate the leading edges and add harshness like regular silver, but it still leans cool.

I have custom built every part of my system from the DAC's output to the speaker drivers, and to me it is unbelievable how much fidelity AND correctness of tone is left on the table by typical consumer audio equipment... few are willing to use the quality of parts required to achieve these levels of performance. One example is Lampizator's new Golden Gate DAC, the main difference with this DAC is uncompromising parts selection vs their other gear, and by all accounts it makes a huge difference.

 

[DaveC]

I actually think of myself as sort of in the middle. I like accurate to the recording, and without distortion or listening fatigue. I also want it to sound natural and convincing with no obvious rolling off of any frequency. I use live acoustic music as my reference. I think most of my local audio buddies feel the same way.

I feel analog LPs sound more accurate and natural at the same time. Most of my friends do to. I don't know what that means for cable technology.

I agree and prefer vinyl and tubes myself. I think you're likely in the high fidelity camp. NOBODY like harsh sound with thin, unrealistic tone! Listening fatigue is poison to audio and needs to be avoided at all costs, if this means losing some resolution than that is a better option vs a fatiguing system. However, it is possible to make gear that combines very high levels of resolution with absolutely no harshness or fatiguing qualities. This is my goal with everything I build. I dislike warmth and harshness, but forced to choose I go with warmth. That is the compromise I make with my lower end cables as well... to hit a certain price point compromises must be made somewhere.

 

[Phelonious Ponk]

Are you asking “what is 'high-fidelity' if it is not a measure of an audio component’s linearity when fed test signals”, or are you asking “what is 'high-fidelity' if it is not a measure of an audio component’s linearity when fed music signals”?

Yes. And I can answer yes to both questions because I believe that sine wave testing is a very good indicator of a components performance. I don't want to put words in your mouth, but it seems that you don't believe that. Also, I know of no way to test the linearity of a single component while playing music.

Tim

 

[PeterA]

I agree and prefer vinyl and tubes myself. I think you're likely in the high fidelity camp. NOBODY like harsh sound with thin, unrealistic tone! Listening fatigue is poison to audio and needs to be avoided at all costs, if this means losing some resolution than that is a better option vs a fatiguing system. However, it is possible to make gear that combines very high levels of resolution with absolutely no harshness or fatiguing qualities. This is my goal with everything I build.

I agree with your statement in bold, and my system strives to demonstrate that. High fidelity is fine, but it has to sound natural to me above anything else. And natural, to me, means very high resolution and great dynamics, tone, and presence.

 

[KeithR]

The whole point is music is essentially sinewaves, and sinewave tests can fully excite the distortions in electronic amplification systems and the truth is that we can enjoy music today with the same tubes and circuits made 100 years ago and with modern transducers and sources that stuff sounds just fine, despite the original testing only done with a lowly single tone at a time sinewave distortion test!

to that end, I'm currently enjoying a set of Quad ii Jubilees- a tube design from 1951. a pair of amps that test quite well on JA's bench keeping in mind their power/impedance restrictions.

on the other side- Dan D'agostino told a group of us that his old preamps measured as pristine as any in the world on any scope- but when people called into Krell, they rarely were using his preamps (they didn't sound very good). It required Dan to think much more on his newer designs which have been much more popular with his amp customers.

 

[Phelonious Ponk]

Yep, sinewave tests reveal distortions. The simplest and oldest test is to put a pure tone into the amp and then subtract it out and whats left is all the added distortions and noise, thus thd+noise. We simply measure the amplitude of all the harmonics (odd and even) created by probing that amp with that continuous sinewave tone. Note that nowadays, we don't have to probe continuously, you can probe with just one sinewave if you want. The amplitude of the input sinewave can exercise the entire usable range of the amplifier. To be more complete in this test you test at all frequencies and amplitudes between 20 and 20khz if you want to be pedantic about it.



Now, the idea to do a better test to reveal more of just how ugly things are is the two tone test. An early version is called an SMPE which was set up by the early adopters of stereo, the movie folks. The reasoning is, as you make your input signal bigger, the amplifier produces more distortions cause in those days you were using tubes, and they like most amplification devices make more distortion the further you push them from their comfort zones. So in music, typical western music, you have some pretty high amplitude drum or bass notes and these are reaching past the comfort zones of the amplifiers, and then at the same time some say guitar at not so loud a volume. Well, during those drum beat peaks we are also listening to that guitar, and this means that the distortion just from the drum beat is also adding to and mixing with the lower guitar note at the same time and so the two together produce some nasty things called sidebands, (just frequencies above and below the drum and guitar) and these are now more readily seen by this multi-tone test.

As can be seen, this test is more realistic of music.

Now, the distortions to a single sinewave through the device would result in addition of harmonics of the original signal itself, no mixing going on hear, so you will hear a change in timbre or tone of the sinewave going through the system, aka listen to a test tone from an LP vs one from a digital source, here you will hear the difference between clean and harmonically rich tone. So, that's the simple sinewave test.

Lets do the one more like music, and thus the second multi tone test. The one with the bass drum and lead guitar we talked about above. Now, if you feed these low and hf tones together, with the low one being several times bigger than the hf one into the amp, now because of the mixing of these two tones due to the non-linearity which is worse at the peaks of the drum beat, we hear harmonically unrelated frequencies (remember with one tone the frequencies we add are harmonically related) and harmonically related too. We are hearing a lot of sheet added now, not just those two pure sinewave input tones, and because these harmonics cluster around the original frequencies they blur the original two tones. Lack of clarity. And because we are hearing these extra non harmonic tones in the midrange, where our ears are more sensitive, even though they are small amplitude compared to the two input sinewaves, they are in our sweet spot for hearing.

However, if you choose different low and high frequencies and levels you can test away with those good old pure sinewave tones and measure till hell freezes over, and get you some results that characterize your system.

Of course nowadays, we can do bursts of tones and look at FFT plots etc and see what is happening on a nice graph.

The point here is that you gather all the information you need about the device under test. You can even do this with a speaker connected and see what comes out of your amp ( it aint pretty) and be amazed we can hear through a stereo system as well as we can.

To 853guy point, yes, in the end, its the full system connection front to back, but you can pass the sinewaves through the entire system if you want and see what comes out the other side, or you can pass music but either way you can listen with the music or observe with test equipment the sinewave tests and see how well your system is doing.

Testing speakers in a room is not done best with a sinewave, but you can if you want.

The whole point is music is essentially sinewaves, and sinewave tests can fully excite the distortions in electronic amplification systems and the truth is that we can enjoy music today with the same tubes and circuits made 100 years ago and with modern transducers and sources that stuff sounds just fine, despite the original testing only done with a lowly single tone at a time sinewave distortion test!

Thanks for the thoughtful reply, Tom. I learned from it. Seems to have quieted this thread.

Tim

 

[853guy]

Yes. And I can answer yes to both questions because I believe that sine wave testing is a very good indicator of a components performance. I don't want to put words in your mouth, but it seems that you don't believe that. Also, I know of no way to test the linearity of a single component while playing music.

Tim

Tim, I’m a bit loath to say what I “believe”, but I’m happy to share what I think I know (that is: what I currently understand but am willing to modify if presented with additional information) as well as what I’ve experienced, even allowing that both those things are often held in tension against one another, however uncomfortable that may sometimes be. “Belief” is perhaps best reserved for those who feel a need to assert their values on others, and I personally have no interest in doing that.

What I can say, is that I think the theory of linearity seems fairly scientifically robust. As I’m sure you already know, a function is linear if and only if the following equation holds: af(x+y) = f(ax) + f(ay)

That is, in order for a function to be linear it must contain two properties 1) Additivity: f(x+y) = f(x) +f(y) and 2) Homogeneity af(x) = f(ax).

No problem with that.

But given that we’re discussing the nature of music reproduction systems - designed primarily, as they are, for playing back music - it’s important for me to ask: Can the mechanism of transducer/amplifier/transducer be considered to be truly linear when playing back a medium in which the content is a time-based art form?

Well, we need to decide whether we’re discussing a problem of mathematics or a problem of description. In mathematics or physics, linearity is easy to measure, because we have an equation defining exactly what it is and what it is not, and the robustness of that equation means we can represent the relationship between two variables graphically and get a straight line, right?There are countless examples, none of which need to be listed here, as I’m sure you covered this in grade school. So far, it doesn’t appear we have a mathematics problem.

A time-based art form like music, if it is to be recorded, needs to capture two variables (pitch and amplitude) against one constant (time). That is, music is a relationship between three entities in which two are modulating and one is constant, and can be graphically represented as a waveform or literally represented as a groove in a record. But wait! Didn’t Einstein’s theory of relativity argue time is not constant? He did indeed, and James Chin-wen Chou managed to illustrate this when two atomic clocks separated in height by 33 centimetres showed time dilation at the National Institute of Standards and Technology in 2010.

Ruh roh! We have a problem then, don’t we? If time is not constant, then we have three variables not two, and this is before we even get to our playback chain, which is required to play back pitch and amplitude over time from a source component that, whether it be digital or analogue, must be constant in the time domain if it is not to affect the pitch and amplitude of the signal. What do we do? Well, we could say Einstein’s theory of relativity is just, y’know, a theory, and one experiment by a lab in Boulder, Colorado hardly makes for definitive and conclusive evidence (they could be making this up, right?). But still, we should probably at least consider whether it’s worth asking, just how accurate should our source components be in the time domain to be considered accurate?

Hmm. We need a real-world example. How about the Antelope Isochrone 10M Master Clock? That has an Atomic oscillator with stability of 1 second in 1,000 years - “a staggering 100,000 times more accurate than the quartz oscillators used in most equipment” (according to their website) - that’s pretty accurate, right? Well, kinda. But quite a bit less accurate than the atomic clocks used at the National Institute of Standards and Technology, which are able to keep time to within 1 second in 3.7 billion years. (That makes the Antelope 3.7 million times less accurate than the ones at the NIST, but they're probably unlikely to include that copy in their future marketing.)

Oh. So really, all we have is “relative” time-domain accuracy - we don’t have a perfectly precise measure of time? Einstein is still right and we should cut James Chin-wen Chou some slack? Mathematically speaking, wouldn’t this mean we can never categorically state the mechanism involved in recording and playing back music can be linear if one of the three entities is not a constant? Are we simply introducing a qualifier - approximation - in order to call something what it is not? Are the only things we’re left with simply components that in-and-of-themselves are and can only ever approximately approach linearity but never achieve it?

Again, I’m not really interested in belief, only what I think I know and holding that which I think I know lightly. And what I think I know is that no component is linear, or for than matter, can be linear, because a component that cannot be precisely stable in time cannot therefore perfectly recreate a time-based art form - it will only ever interpret it. (Sorry if this is offending anyone’s grasp of the bleeding obvious, but I am, afterall, an indie and alternative rock musician who moved from the music industry which has been decribed as “a cruel and shallow money trench, a long plastic hallway where thieves and pimps run free, and good men die like dogs,” (1), into advertising, “which may be described as the science of arresting human intelligence long enough to get money from it”. (2))

The general formula for a sine wave is written as - *y(t) = Asin(?t +*?) - where A is the amplitude, ? the frequency and ? - the phase. Here of course, we can contrast the sine wave with the the musical waveform, which contains all the above, but with constant modulation of the frequency and its occurence in time. A sine wave is neither modulating its frequency, amplitude, nor its occurence in time. We can stack as many sine waves on top of each other as we like, to produce a lot of graphs and numbers, but they still do not represent the constant modulation of frequency (and related harmonics) and amplitude and their occurence in time that are the inherent and defining features of a musical waveform .

So now, I’m back to thinking about the transfer funtion of an ideal amplifier. But I don’t see anyone outside of a few people on this forum (and possibly, other forums, I guess) arguing that the ideal amplifier actually exists, and that it can be linear in the real world. Groucho said:

I don't accept the point about audio systems not being linear from one end to the other. Of course, in practice, they're not literally linear - there are distortions - but there's no reason for a system not to be very close:
- good mics are close to linear;
- digital audio is linear to any arbitrary degree we choose, by definition;
- a solid state amp is linear to all intents and purposes;
- a good speaker transducer is close to linear especially if not driven beyond its limits (so it pays to be clever in how we use them).

As jkeny answered, this still remains the sticking point. Platonic idealism vs Aristotelan realism. One the one hand Groucho isn’t willing to accept an audio system isn’t linear from one end to the other, but introduces a qualifier of approximation in order to hold onto the concept of linearity, even as he admits they can’t literally be linear in the real world, like for instance when we connect our “ideal” solid state amplifier to an actual speaker and play music through it.

So, it seems reasonable for me to think that I know a component that cannot be precisely stable in time cannot therefore perfectly recreate a time-based art form - it will only ever interpret it (or, if you prefer more prosaic language, distort it). Futhermore, it appears to me that when describing audio systems we are using a very strictly-defined mathematical and scientific term - “linear” - in the context of approximation, such as when we state a component offers “superb measured performance” within the context of what is likely to be considered audible. That is still a qualifier, and neither mathematics nor science seems to need to use those when considering what is linear and what is not.

Just sayin’.


You asked:

If the "accuracy" of an audio component is not "high fidelity," if it's not the ability of that component to put out the signal it receives with the least amount of distortion of that signal possible, what is it?

My answer is: Er, to attain market share?

I don’t know, Tim. I don’t design, manufacture or market audio components. I’m an end-user who’s fairly agnostic in regard to format, transistors, thermionic devices, stats, planars, dynamics and horns. I try not to make sweeping generalisations in regard to anything, so I think it’s a question best asked of those in the business of making and marketing them.


(1)Hunter S. Thompson’s full quote is: “The music business is a cruel and shallow money trench, a long plastic hallway where thieves and pimps run free, and good men die like dogs. There's also a negative side.”

(2) Stephen Butler Leacock

 

[853guy]

853guy,

I am enjoying your posts, and I appreciate your effort to be analytically consistent!

Thanks Ron, I'm really enjoying this thread, and appreciate you starting it!