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post #121 of 141
Quote:
Originally Posted by Mac-sochist View Post

the severely limited quality of CD sound

CD sound quality is not "severely limited".

Quote:
Originally Posted by Mac-sochist View Post

and this 128,000 bps, ear-destroying noise that people who never learned any better are now willing to pay money for.

I agree that this is unfortunate. Where are our lossless downloads Apple?


Quote:
Originally Posted by Mac-sochist View Post

it destroyed both the SACD and DVD-Audio formats at birth.

Oh well. Never mind. The only properly conducted double-blind comparison between DVD-Audio, SACD and "CD quality" that I'm aware of (abstract here) showed that no-one can hear the difference. I must say that I was very surprised but there you go. The problem isn't CD's 16 bit, 44.1 kHz PCM but the fact that so many CDs are horrendously mastered (lots of dynamic compression etc.)
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post #122 of 141
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Originally Posted by Mr. H View Post

The problem isn't CD's 16 bit, 44.1 kHz PCM but the fact that so many CDs are horrendously mastered (lots of dynamic compression etc.)

I agree the quality of CDs varies enormously and some of the good ones are very, very good. I also agree that the 44.1 kHz sampling rate is just fine. The 16-bit dynamic range is also all right for pop music (now that they don't try to stretch the envelope any more like they did in the 60s and 70s,) but in the quiet stretches of orchestral music where they're only using maybe 4 bits of that, it can result in artifacts that are really horrifying.

Anyway, "CDs are dead." That's what they keep telling us!
post #123 of 141
Quote:
Originally Posted by Mac-sochist View Post

Anyway, "CDs are dead." That's what they keep telling us!

In last years September Special Event keynote Jobs stated that 32% of all music sold in 2006 was not even released on CD. There is obviously a marketing spin in there somewhere, so I assume that there are a lot of indie bands on eMusic being counted. That doesn't mean that the move isn't happening, but if how many popular artists/major labels are only releasing digital copies of their music?
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post #124 of 141
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Originally Posted by solipsism View Post

In last years September Special Event keynote Jobs stated that 32% of all music sold in 2006 was not even released on CD. There is obviously a marketing spin in there somewhere, so I assume that there are a lot of indie bands on eMusic being counted. That doesn't mean that the move isn't happening, but if how many popular artists/major labels are only releasing digital copies of their music?

I don't know, but it would be interesting to find out. What I worry about is that all this "optical media are dead" hoopla will turn into another one of these self-fulfilling prophecies. You have the techno-intelligentsia pushing it from one side, and the RIAA would like nothing better than to put the genie back in the bottle and slap DRM on everything.
post #125 of 141
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Originally Posted by JeffDM View Post

How big is that audience? How many people visit this country's fine art photo galleries in a year?

millions

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No, I very clearly said that it's elitist of you to say I'm not really interested in photography because I don't agree with your views. As in "everyone that disagrees is heathen".

No, that wasn't it at all. As I explained later, I have nothing against your level of interest. What you don't have is a high interest that involves making prints that require larger sizes for the proper impact, which then require much higher quality.

Since even "amateurs are buying 13' x 19" printers in very large numbers, almost a million a year by some estimates, there is a large interest in work done beyond 8/5 x 11. More advanced amateurs and professionals are buying printers like my Canon ipf5100, or equivalent Epson and Hp. Pros are also buying machines from these companies up to 60".

The many high quality, and expensive printing papers available today are more evidence for that.

The fact that about 7 million D-SLR's were sold around the world last year is also an indication.

You're ignoring all of this very carefully in your arguments. All you want to talk about is casual shooters, when you know that I'm not talking about them. They are in their world of pictures, and we are in ours.

I don't bemoan the level of their work, and I don't expect them to bemoan mine.

I'm not saying that you have no interest at all, the mere fact that you do print shows that you have some interest. But your interest level isn't in depth. If you really were interested at the level many of us are, you wouldn't be arguing with me about this. You would understand.
post #126 of 141
Quote:
Originally Posted by melgross View Post

That doesn't look as though its a detriment right now, when compared to Windows. Performance wise, Vista has been a dog. It's only recently that most of that has been fixed. Comparable programs also seem to perform about the same on both platforms.

Who in their right mind using Vista today, wouldn't upgrade to Vista SP1? We are at least talking about current or future OS'es, are we not?

Oh, and we seem to be comparing a future OS to a present OS, and AI is choosing to compare a particular version of the present OS disproportionately 32-bit x86 Vista (or XP). And yes, most people use 32-bit Windows, because that's all they needed in the first place to begin with. Those that need a 64-bit OS move to a 64-bit OS at their choosing, one that runs 99.44% of all 32-bit Windows applications.

And since we're talking about possible future OS'es why I think Vista SP2 will be released before the Snow Leopard bata's (10.6.0, 10.6.1, 10.6.2, 10.6.3, ad infinitum, ad nauseam).

It seems as if Snow Leopard is a fix for the premature release of Leopard, a flashy hood ornament is a flashy hood ornament, when all I wanted in the first place was to have the engine fixed.

Perform about the same? My original point about parity was taken then?
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post #127 of 141
Quote:
Originally Posted by Mac-sochist View Post

The 16-bit dynamic range is also all right for pop music (now that they don't try to stretch the envelope any more like they did in the 60s and 70s,) but in the quiet stretches of orchestral music where they're only using maybe 4 bits of that, it can result in artifacts that are really horrifying.

I used to think that the 16 bit resolution wasn't quite high enough and that 19 or 20 bits were necessary for ultimate fidelity with respect to the capabilities of the human ear. However, that study I linked to used music of all different types and highly experienced listeners, and not a single one of them could hear the difference between DVD-audio/SACD and CD quality. So I have to conclude, until any contrary evidence from a study of at least equal thoroughness, that 16 bit resolution is fine for all music. It still gives a much, much bigger dynamic range than vinyl and I don't hear people complaining about classical on vinyl.
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post #128 of 141
Quote:
Originally Posted by Mr. H View Post

...It still gives a much, much bigger dynamic range than vinyl and I don't hear people complaining about classical on vinyl.

The problem isn't dynamic range per se, it's digitization error when only a small part of that range is being used. Vinyl, being analog, didn't have that problem. Of course, it had its own problems, and I think the aficionados who cling to analog as being somehow superior in this day and age are misguided; especially since every vinyl record was digitally mastered anyway. (Of course, that's on recorders with much greater than 16-bit resolution.)

Artifacts and distortion are not all created equal. The problems to which vinyl was heir (noise, limited dynamic range, etc.) are annoyances that occur in the natural environment. Our auditory cortex has evolved to filter them out and listen past them. That's not true of some of the distortions that have been introduced by technology and that it was blithely assumed "no one could hear."

The first solid-state amplifiers did very well on harmonic distortion, but they used a push-pull arrangement, which while the characteristic curve looked nice and linear in the middle, thus introducing no harmonics, did have a discontinuity there which introduced "anharmonic distortion," something nobody was checking for, and something that never happens in the real world, giving a sound quality that was absolutely intolerable. But measured distortion was low, so who cared?

The first CD players use analog filters to remove everything above 20 kHz. It was by definition "noise" since it couldn't be recorded on the disc at that sampling rate. Unfortunately, they used a Chebyshev filter, which gives a nice flat frequency response, but introduces phase distortion close to the upper limit: another thing "nobody could hear." Well, they could!

Stereo was designed to create an illusion of localization by simply varying the loudness of the signal to move the apparent location from coincidence with the left speaker to coincidence with the right, and in between. Unfortunately, if a rapid-onset sound like a drumbeat reaches the ears in the real world, you will hear two arrival times, one for each ear. In stereo reproduction you get four, two for each speaker, which creates confusion in the auditory cortex and prevents stereo from working as advertised. Phase was another thing the human ear couldn't detect, and since it was tested with continuous sine waves, that was true: until you listen to real music! (Of course five-channel gives you ten arrival times to sort out!) The only solution is headphones (but they don't allow a real perception of sound coming from straight ahead; it will seem to rise up kind of above your head) or Carver Sonic Holography, which died with the second of the three corporations Bob Carver had stolen out from under him by insensate bean-counters.

The list of things "the human ear can't detect" is added to every time a new technology comes along, and usually disproven. Only this time, it seems like crappy music downloads are finally going to make it stick!
post #129 of 141
Quote:
Originally Posted by Mac-sochist View Post

The problem isn't dynamic range per se, it's digitization error when only a small part of that range is being used. Vinyl, being analog, didn't have that problem.

Sorry, but this is a popular misconception and simply wrong. There is absolutely zero difference between quantisation (done properly with dithering) and the noise inherent in the vinyl medium.

Taking a sample, dithering it and converting it to a number with 16 bit accuracy is exactly the same as recording that sample onto an analogue medium with a 96 dB noise floor (note we're talking here just about the quantisation to 16 bit, not the sampling rate). Vinyl has a noise floor of 75 dB. This "digitization error" of which you speak is noise, pure and simple.

Quote:
Originally Posted by Mac-sochist View Post

The first solid-state amplifiers did very well on harmonic distortion, but they used a push-pull arrangement

There's nothing wrong with push-pull. However, the first solid-state amplifiers, whilst they did have better THD numbers than valve amplifiers, used "quasi-complimentary" output stages using all-NPN output devices, rather than NPN/PNP matched pair. This is because no-one at the time was manufacturing PNP power transistors with the necessary high-frequency performance (fT). Quasi-complimentary output stages have quite horrible cross-over regions. This means that they produce many high-order harmonics in contrast to valve amplifiers which generate mainly second harmonic distortion. Second harmonic distortion generally adds "warmth" to a signal and therefore sounds more pleasant than an objectively "more accurate" amplifier producing high-order harmonics.

Quote:
Originally Posted by Mac-sochist View Post

which while the characteristic curve looked nice and linear in the middle, thus introducing no harmonics, did have a discontinuity there which introduced "anharmonic distortion,"

If an amplifier distorts a signal with a discontinuity as you state, it must necessarily produce harmonic distortion. The only way of having "anharmonic distortion" is by the amplifier literally generating its own signals. If you've got a link to a proper technical paper on this, I'd love to see it.
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post #130 of 141
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Originally Posted by Mr. H View Post

CD sound quality is not "severely limited".

I agree that this is unfortunate. Where are our lossless downloads Apple?

Oh well. Never mind. The only properly conducted double-blind comparison between DVD-Audio, SACD and "CD quality" that I'm aware of (abstract here) showed that no-one can hear the difference. I must say that I was very surprised but there you go. The problem isn't CD's 16 bit, 44.1 kHz PCM but the fact that so many CDs are horrendously mastered (lots of dynamic compression etc.)

As some here know, I'm an audiophile, and have designed quipment commercially, for my own firm, and others.

Having said that, I don't hear the difference either.

You are correct about the mastering. Stan Richter, one of the great engineers, one said, in regard to Telarc's better sounding gold CD's, that it wasn't the gold that made them sound better (though many audiophiles do think that), but the higher price of the recordings allowed them more time to get the mastering "right".

Having done live recording and mastering myself, I agree that high quality mastering, or the lack of same, is one of the biggest determinators of how high the quality of the album will be. That's assuming that they got the original recording right, which doesn't always happen. Then you have the mastering chasing the recording to no good effect.

This is true for SACD as well, though I'll get an argument about that if there're any "blue blood" audiophiles present. In the beginning, Sony made some really dynamite SACD's. They did sound great. But, I'm pretty sure that the mastering was great as well, and they selected only works that were recorded very well also. Over time, fewer SACD's sounded so great, because more companies were making them, and as they became more common, standards, as usual, in the chase for the buck, went down. So some sound great, and some don't.

Beside, it's on the way out. The PS3, surprisingly, doesn't support it, which tells us something.
post #131 of 141
Quote:
Originally Posted by Mac-sochist View Post

I agree the quality of CDs varies enormously and some of the good ones are very, very good. I also agree that the 44.1 kHz sampling rate is just fine. The 16-bit dynamic range is also all right for pop music (now that they don't try to stretch the envelope any more like they did in the 60s and 70s,) but in the quiet stretches of orchestral music where they're only using maybe 4 bits of that, it can result in artifacts that are really horrifying.

Anyway, "CDs are dead." That's what they keep telling us!

Let me explain a little *bit* (PUN zone!) about this.

16 44.1 is really fine. But, it's understood that 18 48 is better. It's better by just a little bit. But it is better. Does it matter? Not really. But it's about the most we can hear, given really good equipment, (and mastering!).

John Eargle, one of the best known people in the music business, as producer engineer, and researcher, has said the 18 48 would be all that we would ever need for listening purposes. Archival storage is another thing. 24 94 is better for that.

The problem we have with 24 96 is that there is no equipment now, or likely in the future (as a practical matter), that can properly reproduce it. 24 bits is 144 db of dynamic range, and that's well beyond any dynamic range an electronic component can deliver. In fact, even SACD players can't reproduce it at their outputs! 18 bits is a good practical limitation.

As for 96 KHz sampling rate, well it costs little these days to do it, so...

But it serves little purpose for audio, even with the noise shaping that SACD does.
post #132 of 141
Quote:
Originally Posted by franksargent View Post

Who in their right mind using Vista today, wouldn't upgrade to Vista SP1? We are at least talking about current or future OS'es, are we not?

Oh, and we seem to be comparing a future OS to a present OS, and AI is choosing to compare a particular version of the present OS disproportionately 32-bit x86 Vista (or XP). And yes, most people use 32-bit Windows, because that's all they needed in the first place to begin with. Those that need a 64-bit OS move to a 64-bit OS at their choosing, one that runs 99.44% of all 32-bit Windows applications.

And since we're talking about possible future OS'es why I think Vista SP2 will be released before the Snow Leopard bata's (10.6.0, 10.6.1, 10.6.2, 10.6.3, ad infinitum, ad nauseam).

It seems as if Snow Leopard is a fix for the premature release of Leopard, a flashy hood ornament is a flashy hood ornament, when all I wanted in the first place was to have the engine fixed.

Perform about the same? My original point about parity was taken then?

Well now, let's see. Even Vista SP1 requires computers that are close to the top of the range now, if you expect Aero to take off. If you take the machines that were being sold originally as being "Vista ready", that really weren't, and you include all of the Aero "experience", they are still running slowly with the full GUI running.

What MS has speeded up is some problems playing a number of games and the like. But, Vista is still slow, when compared to XP.
post #133 of 141
Quote:
Originally Posted by Mr. H View Post

Sorry, but this is a popular misconception and simply wrong. There is absolutely zero difference between quantisation (done properly with dithering) and the noise inherent in the vinyl medium.

This section of John Watkinson's book "The Art of Sound Reproduction" seems to disagree with this and shows how anharmonic distortion can arise in low-level sound in digital recording, too. You learn something new every day!

Quote:
Originally Posted by Mr. H View Post

There's nothing wrong with push-pull. However, the first solid-state amplifiers, whilst they did have better THD numbers than valve amplifiers, used "quasi-complimentary" output stages using all-NPN output devices, rather than NPN/PNP matched pair. This is because no-one at the time was manufacturing PNP power transistors with the necessary high-frequency performance (fT). Quasi-complimentary output stages have quite horrible cross-over regions. This means that they produce many high-order harmonics in contrast to valve amplifiers which generate mainly second harmonic distortion. Second harmonic distortion generally adds "warmth" to a signal and therefore sounds more pleasant than an objectively "more accurate" amplifier producing high-order harmonics.

Thanks for pointing that out. I know there's nothing inherently wrong with push-pull amps, but I had forgotten the flaw in the first solid-state audio amplifiers.

Quote:
Originally Posted by Mr. H View Post

If an amplifier distorts a signal with a discontinuity as you state, it must necessarily produce harmonic distortion. The only way of having "anharmonic distortion" is by the amplifier literally generating its own signals. If you've got a link to a proper technical paper on this, I'd love to see it.

Here's an article dealing with how anharmonic distortion arises when an amp is challenged with a chord instead of the pure tones most are tested with. Undoubtedly sum and difference frequencies result which are not harmonics of any of the components. (He finds that single-ended amps are worse than push-pull in this aspect.)

I got roped into doing something tonight, but I'll keep looking for references. I'm sure I must have read this in Stereo Review or Audiophile many, many years ago, but it stands to reason that a singularity in any function can lead to bizarre, unpredictable results. That's why Stephen Hawking postulated the "Cosmic Censorship Conjecture" to keep them confined inside the event horizons of black holes!
post #134 of 141
Quote:
Originally Posted by Mac-sochist View Post

The problem isn't dynamic range per se, it's digitization error when only a small part of that range is being used.

That problem, quantization error, isn't really a problem, because it was understood quite early in the CD era. Convolution (dithering) of the low bit signal (such as you hear in the last embers of a final piano tone) has eliminated that problem.

Also, while that is a theoretical problem, it isn't much of a practical one. The low level signals that you are talking about are already so low in volume, that the residual distortion caused by this is so much further down in level so as to be unhearable, unless you press to the speaker. We're talking about components that are 100 db down! Lower than the noise level of most components the signal is passing through.

Quote:
Artifacts and distortion are not all created equal. The problems to which vinyl was heir (noise, limited dynamic range, etc.) are annoyances that occur in the natural environment. Our auditory cortex has evolved to filter them out and listen past them. That's not true of some of the distortions that have been introduced by technology and that it was blithely assumed "no one could hear."

I've been to many a live concert over the years, and I've yet to hear any of the distortions that vinyl is subject to, there.

We certainly haven't evolved to hear record noise, harmonic and IM distortion, etc. It's very obvious when playing records, and when listening to certain tube equipment.

I've yet to see any actual proof, done through properly set-up listening tests, that show that we can hear the very low level distortions of a good CD, but not that of a good Lp. I'd love to see one.

Most of this is hearsay, from people who have an interest in believing so.

Quote:
The first solid-state amplifiers did very well on harmonic distortion, but they used a push-pull arrangement, which while the characteristic curve looked nice and linear in the middle, thus introducing no harmonics, did have a discontinuity there which introduced "anharmonic distortion," something nobody was checking for, and something that never happens in the real world, giving a sound quality that was absolutely intolerable. But measured distortion was low, so who cared?

Uh, what are you talking about? The earlier solid state amps used quasi-complementary circuits. Before that, they weren't even that sophisticated.

But the problems of early (through the early '70's, to about 1972-3) solid state amps were due to a type of distortion called "TIM", or transient Intermodulation Distortion. This occurred for two reasons. One was that solid state amps had a much more extended high frequency range when compared to tube amps of that time. Two was that early transistors had a low frequency range. That sounds incompatible, and it IS. Once they recognized that TIM was the cause, they rapidly eliminated it. I'm not going to get into the theory involved, but will say that the problem wasn't recognized early on because tubes, due to their nature, weren't reproducing it because of the high frequency roll-off (and other reasons). Therefore, it didn't occur to engineers that TIM could exist in an audio amp.

"Push Pull" was invented in the late '40's by Williamson. It was first used for tube amps, because solid state wasn't around then. In honor, that amp design is called the "Williamson Amp".

It is the first modern amp design. Before that, all amps were of the type called "SLT", or "Single Ended Tube". All amplification was done with a positive going signal. But that kind of amp has many problems, and died out quickly after the "push pull' came out. More recently, it has made a comeback amongst a certain group of audiophiles who don't mind its high distortion, poor frequency response, and very low power. They claim that it has other qualities that more modern tube and SST amps lack.

Quote:
The first CD players use analog filters to remove everything above 20 kHz. It was by definition "noise" since it couldn't be recorded on the disc at that sampling rate. Unfortunately, they used a Chebyshev filter, which gives a nice flat frequency response, but introduces phase distortion close to the upper limit: another thing "nobody could hear." Well, they could!

"Brick Wall filters have their problems. The biggest problem was that of "ringing". At the filter point, the frequency response is unstable, and "rings". That is, it varies about the cutoff point. Some people claim to hear it, while others don't. The actual frequency is about 21.5 KHz, which is above the hearing limits of most younger adults (about 23 and up, if they are lucky, if not, 16 and up)).

Phase distortion is interesting. When designing speakers and anything using filters, it was something I had to deal with. Unfortunately, phase shifting is something that can't be eliminated in the analog world. That's because it's the phase shift itself that's doing the work. No phase shift, no filtering!

What is well understood about phase shifts and human hearing, is that we can't detect slow phase shifts. That is, phase shifting over a long frequency range. If phase is +720 degrees at 50 Hz, and -720 degrees at 15 KHz, we won't hear it. But, if phase shifts from, say, +180 degrees to -180 degrees between 750 Hz and 1,250 Hz, we will hear it.

It's debatable if phase shifts at. or above. 21 KHz is audible though. If we can't hear the frequency involved, then it's not likely we will hear the phase shift associated with it, which is moving up in frequency, not down.

Quote:
Stereo was designed to create an illusion of localization by simply varying the loudness of the signal to move the apparent location from coincidence with the left speaker to coincidence with the right, and in between. Unfortunately, if a rapid-onset sound like a drumbeat reaches the ears in the real world, you will hear two arrival times, one for each ear. In stereo reproduction you get four, two for each speaker, which creates confusion in the auditory cortex and prevents stereo from working as advertised. Phase was another thing the human ear couldn't detect, and since it was tested with continuous sine waves, that was true: until you listen to real music! (Of course five-channel gives you ten arrival times to sort out!) The only solution is headphones (but they don't allow a real perception of sound coming from straight ahead; it will seem to rise up kind of above your head) or Carver Sonic Holography™, which died with the second of the three corporations Bob Carver had stolen out from under him by insensate bean-counters.

While I understand what you are saying, it's wrong. It's well understood that stereo works. That's not the problem. It only takes a 9 db difference in level to mask out the other channel completely for a similar sound in stereo reproduction. There is also the time difference, which is most certainly on both the Lp and the CD.

How do you think the microphones pick this up? They are in different places, and "hear" the music at different times, with difference loudness, and phase. This is reproduced in the recording.

Sometimes binaural microphones are used, where a simulated head is used, with the omnidirectional mics where the ears are. They get the same spacial relationships we get. The "cross mic" set-up is also sometimes used. That's where two (usually) cardiod mics are crossed over each other so that the left mic points towards to right and vica versa.

I happen to know Bob Carver from way back. His ideas were well ahead of their time back then, but are still being used today.

He invented quite a few things, but Sonic Holography was an interesting one. It's actually the basis of most multichannel systems today.

The biggest problem Bob had with it, was that he was trying to do something in the analog domain that was better done in the digital domain. The problem was that there WAS no digital domain when he was working with this! It was amazing that it worked at all, much less as well as it did.

Quote:
The list of things "the human ear can't detect" is added to every time a new technology comes along, and usually disproven. Only this time, it seems like crappy music downloads are finally going to make it stick!

Unfortunately, we can't detect many things some think we can detect. While our eyes are given one million neurons to work with, our ears must make do with thirty thousand. We can;t discriminate as much as we like to think we can. Again, as I said earlier, hearsay is worthless. Without proper listening tests, we can think anything we like. And thats fine, just as long as we don't push it upon others.

I'm always happy for someone when they tell me that the equipment they now have is enabling them to enjoy their music more than ever before, even if that equipment make me want to cringe.
post #135 of 141
Quote:
Originally Posted by Mr. H View Post

Sorry, but this is a popular misconception and simply wrong. There is absolutely zero difference between quantisation (done properly with dithering) and the noise inherent in the vinyl medium.

Taking a sample, dithering it and converting it to a number with 16 bit accuracy is exactly the same as recording that sample onto an analogue medium with a 96 dB noise floor (note we're talking here just about the quantisation to 16 bit, not the sampling rate). Vinyl has a noise floor of 75 dB. This "digitization error" of which you speak is noise, pure and simple.

There's nothing wrong with push-pull. However, the first solid-state amplifiers, whilst they did have better THD numbers than valve amplifiers, used "quasi-complimentary" output stages using all-NPN output devices, rather than NPN/PNP matched pair. This is because no-one at the time was manufacturing PNP power transistors with the necessary high-frequency performance (fT). Quasi-complimentary output stages have quite horrible cross-over regions. This means that they produce many high-order harmonics in contrast to valve amplifiers which generate mainly second harmonic distortion. Second harmonic distortion generally adds "warmth" to a signal and therefore sounds more pleasant than an objectively "more accurate" amplifier producing high-order harmonics.

If an amplifier distorts a signal with a discontinuity as you state, it must necessarily produce harmonic distortion. The only way of having "anharmonic distortion" is by the amplifier literally generating its own signals. If you've got a link to a proper technical paper on this, I'd love to see it.

Gee, too bad I didn't get to your post before posting mine. I could have shortened it.

I agree with what you've written here, as I'm sure you could tell from my preceeding post.
post #136 of 141
Quote:
Originally Posted by Mac-sochist View Post

This section of John Watkinson's book "The Art of Sound Reproduction" seems to disagree with this and shows how anharmonic distortion can arise in low-level sound in digital recording, too. You learn something new every day!

I'm familiar with that book, as is anyone who has worked in audio.

But, what you are missing here is his conclusion, which everyone agrees eliminates quantization error as being relevant.

Quote:
There is little point in studying the adverse effects further as they should be and can be eliminated completely in practical equipment by the user of dither.

(a form of the convolution I mentioned earlier in my other post)

This is all well understood and characterized. Except for the first recordings done in the first year or so, no recordings have been released without proper dithering. It's likely that the first ones that had no dithering were dithered as more copies were made.


Quote:
Here's an article dealing with how anharmonic distortion arises when an amp is challenged with a chord instead of the pure tones most are tested with. Undoubtedly sum and difference frequencies result which are not harmonics of any of the components. (He finds that single-ended amps are worse than push-pull in this aspect.)

This is well known.
Quote:
I got roped into doing something tonight, but I'll keep looking for references. I'm sure I must have read this in Stereo Review or Audiophile many, many years ago, but it stands to reason that a singularity in any function can lead to bizarre, unpredictable results. That's why Stephen Hawking postulated the "Cosmic Censorship Conjecture" to keep them confined inside the event horizons of black holes!

You mean Audio? I don't recall a magazine just called Audiophile.

I'm assuming that last was a joke?
post #137 of 141
We'll just have to agree to disagree on a lot of this, but this has been a very interesting discussion.

Quote:
Originally Posted by melgross View Post

We certainly haven't evolved to hear record noise, harmonic and IM distortion, etc. It's very obvious when playing records, and when listen to certain tube equipment.

I think noise is very much a part of the natural environment, and unless you live in an anechoic chamber, any sound is going to vibrate other objects in the environment and create harmonics. So, yes, I think our hearing has evolved to allow for this and to some extent tune it out.

Quote:
Originally Posted by melgross View Post

"Push Pull" was invented in the late '40's by Williamson. It was first used for tube amps, because solid state wasn't around then. In honor, that amp design is called the "Williamson Amp".

Yeah, my Williamson-circuit monoblocs I built 35 years ago sound more musical and pleasant (even if their specs don't bear that out) than any other amp I've owned until the Carver Magnetic Field Amplifier came along. (Of course, it's not really an amplifier, but a switching power supply that tracks the input.)

Quote:
Originally Posted by melgross View Post

It is the first modern amp design. Before that, all amps were of the type called "SLT", or "Single Ended Tube". All amplification was done with a positive going signal. But that kind of amp has many problems, and died out quickly after the "push pull' came out. More recently, it has made a comeback amongst a certain group of audiophiles who don't mind its high distortion, poor frequency response, and very low power. They claim that it has other qualities that more modern tube and SST amps lack.

I freely admit that a lot of self-described audiophiles have some pretty weird ideas, including (probably) me.

Quote:
Originally Posted by melgross View Post

"Brick Wall filters have their problems. The biggest problem was that of "ringing". At the filter point, the frequency response is unstable, and "rings". That is, it varies about the cutoff point. Some people claim to hear it, while others don't. The actual frequency is about 21.5 KHz, which is above the hearing limits of most younger adults (about 23 and up, if they are lucky, if not, 16 and up)).

I think the problem was that the Chebyshev filter they used caused phase distortion way down the audio range where people can hear it. It's my understanding that they chose it over the...Pratt (?) filter, because it caused oscillations (ringing) in the frequency response, which they considered undesirable, while they thought the human ear couldn't distinguish phase distortion. Apparently they were wrong, because the early CD players were roundly panned. It's all handles in the digital domain now, anyway, so that's moot.

Quote:
Originally Posted by melgross View Post

I happen to know Bob Carver from way back. His ideas were well ahead of their time back then, but are still being used today.

That's interesting! I've been following his work since Phase Linear was operating out of the basement of the A&P store in Edmonds. In fact, a buddy and I went up there pretending to be looking for jobs and got a tour of the place. Unfortunately, Bob wasn't there, so I've never met him. If anybody from around here should be a billionaire, it's him and not Bill Gates!

Quote:
Originally Posted by melgross View Post

The biggest problem Bob had with it, was that he was trying to do something in the analog domain that was better done in the digital domain. The problem was that there WAS no digital domain when he was working with this! It was amazing that it worked at all, much less as well as it did.

All I can say is that Sonic Holography works. The stereo imaging when properly placed is unbelievable, and it can make sounds appear to come from beyond the confines of the two speakers. Dolby Surround, which is so common now, addresses the opposite problem of keeping sound from being "pinned" to the closest speaker.

Quote:
Originally Posted by melgross View Post

I'm always happy for someone when they tell me that the equipment they now have is enabling them to enjoy their music more than ever before, even if that equipment make me want to cringe.

This is the bottom line. What I don't enjoy is being told by kids who have never heard good sound that nobody can tell the difference between a quality recording played over a good sound system and 128,000 bps "sound" played through a $5 audio circuit into 89-cent earbuds. Unfortunately, you and I are both dinosaurs, and that's the future. True quality in audio is such a niche market now that it's out of my price range.
post #138 of 141
Quote:
Originally Posted by melgross View Post

You mean Audio? I don't recall a magazine just called Audiophile.

Sorry, I got Audio mixed up with Stereophile, which is a little too far towards the lunatic fringe of the audiophile spectrum for me.

Quote:
Originally Posted by melgross View Post

I'm assuming that last was a joke?

Not at all, a singularity in any mathematical function (like the characteristic curve of an amplifier) can produce totally unexpected results. That's why they don't let you divide by zero.
post #139 of 141
Quote:
Originally Posted by Mac-sochist View Post

We'll just have to agree to disagree on a lot of this, but this has been a very interesting discussion.

I think noise is very much a part of the natural environment, and unless you live in an anechoic chamber, any sound is going to vibrate other objects in the environment and create harmonics. So, yes, I think our hearing has evolved to allow for this and to some extent tune it out.

Noise in the environment is very different from the steady state noise we hear in audio equipment, mostly Lp's, cassettes, and tubes.

We evolved to hear natural sounds, not manmade ones.

It's interesting that just earlier today, I was looking through one of my science journals, Science, that I am going to throw out, as I keep them for a month or two to get to finish reading them. This almost missed our discussion.

The issue is Vol. 321 page 189. The article is "Major European Cities Are Quietly Missing Antinoise Deadline"

I think you can tell what it's about.

A quote:

Quote:
People are far more tolerant of sound levels depending on the context and source, researchers noted at the meeting. Relatively loud natural sounds from birds and water, for example, can put people at ease, whereas quieter sources, such as an electrical buzz, cause stress.

I hope that helps.

Quote:
Yeah, my Williamson-circuit monoblocs I built 35 years ago sound more musical and pleasant (even if their specs don't bear that out) than any other amp I've owned until the Carver Magnetic Field Amplifier came along. (Of course, it's not really an amplifier, but a switching power supply that tracks the input.)

There's really no such thing as a power AMP. All that's happening, really, is that the power from the supply is being modulated by the front end of the circuit, and the output tubes, or transistors. They just allow more or less of the power that's already coming in from the supply to be passed to the speakers.

Quote:
I freely admit that a lot of self-described audiophiles have some pretty weird ideas, including (probably) me.

Sadly, that's become part of the audiophile requirement. Mostly on the High End side.

Quote:
I think the problem was that the Chebyshev filter they used caused phase distortion way down the audio range where people can hear it. It's my understanding that they chose it over the...Pratt (?) filter, because it caused oscillations (ringing) in the frequency response, which they considered undesirable, while they thought the human ear couldn't distinguish phase distortion. Apparently they were wrong, because the early CD players were roundly panned. It's all handles in the digital domain now, anyway, so that's moot.

All brick wall filters have ringing, that was the main problem. They went to slower filters that passed through over a frequency range, rather than doing it suddenly. But, then they went to digital filters, and the problem became moot.

Quote:
That's interesting! I've been following his work since Phase Linear was operating out of the basement of the A&P store in Edmonds. In fact, a buddy and I went up there pretending to be looking for jobs and got a tour of the place. Unfortunately, Bob wasn't there, so I've never met him. If anybody from around here should be a billionaire, it's him and not Bill Gates!

Oh, if you ask him, he will happily tell you that he should be a billionaire.

He's been playing around a lot lately. Here's his latest "hobby" stuff:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=180275596145

Quote:
All I can say is that Sonic Holography works. The stereo imaging when properly placed is unbelievable, and it can make sounds appear to come from beyond the confines of the two speakers. Dolby Surround, which is so common now, addresses the opposite problem of keeping sound from being "pinned" to the closest speaker.

It does work. It would work much better doing it digitally. My friend Ralph has been doing work somewhat smilar to this for a while. It's called Ambiophonics.

http://www.ambiophonics.org/

Quote:
This is the bottom line. What I don't enjoy is being told by kids who have never heard good sound that nobody can tell the difference between a quality recording played over a good sound system and 128,000 bps "sound" played through a $5 audio circuit into 89-cent earbuds. Unfortunately, you and I are both dinosaurs, and that's the future. True quality in audio is such a niche market now that it's out of my price range.

Totally agree with you there, but I do have hope! My system is in the low five figure range (though I've poked around with it over the years, of course). I've got Carver Platinums for the front channels, that I've modified. When I called Bob to tell him what I had done, he had a hissy fit for several minutes. Then, as usual, he stopped, and said, Hey! That could work! Too bad they were already discontinued.
post #140 of 141
Quote:
Originally Posted by Mac-sochist View Post

Sorry, I got Audio mixed up with Stereophile, which is a little too far towards the lunatic fringe of the audiophile spectrum for me.

Stereophile is a lot of fun. I know most of the guys, and call them up, or send an e-mail, when they really say something overboard.

I do like John's testing though. He's about the only one that really does it anymore, and it's valuable.

Quote:
Not at all, a singularity in any mathematical function (like the characteristic curve of an amplifier) can produce totally unexpected results. That's why they don't let you divide by zero.

I usually think of a singularity the way we do in math, or physics, which is to say, an infinity, an impossibility. It's usually meant, in literature, and some popular semi science books as a "coming together", such as in Ray Kurzweil's The Singularity.
post #141 of 141
Quote:
Originally Posted by Mac-sochist View Post

This section of John Watkinson's book "The Art of Sound Reproduction" seems to disagree with this and shows how anharmonic distortion can arise in low-level sound in digital recording, too. You learn something new every day!

Thanks for that link, looks pretty good. However, you need to keep reading to the "dither" section. As I said, quantisation is exactly the same as noise, if done properly with dither. Without dither, the problems in the section you linked to do indeed occur.


Quote:
Originally Posted by Mac-sochist View Post

Here's an article dealing with how anharmonic distortion arises when an amp is challenged with a chord instead of the pure tones

Ah, you were talking about intermodulation distortion. Fortunately a well-designed modern amplifier has extremely low IMD (much lower than a valve amplifier).
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