janneman said:
John Curl (and some other engineers) have the opposite approach.
So, it looks like ones' view on this matter isn't correlated directly with being an engineer.
janneman said:
Those you do not measure.
A hint: you have to evaluate the whole audio chain (including source, cables, everything), this is true not only for listening, but for measurements as well.
SY said:
Stuart,
I agree that it is difficult to correlate sonics with measurements. But it isn't really required. It is only required to make sure that the non-linearities or whatever you want to call amplifier shortcomings are at least an order of magnitude below audibility.
What have a Halcro, a JC-x and an AYRE in common? Good sound, thats about all they have in common. Their execution, high feedback to no feedback and in between, and a lot of other concepts are different. Yet, they all sound great. Isn't that interesting?
Take for instance Bob Cordell's workshop at RMAF2006. Most listeners had a very hard time to hear any difference between a 30WPC tube amp and a 100WPC high feedback SS amp - except, and this is crucial, when they were driven hard: the tube amp was (because of it's lower power) clipping earlier and more often. That gave it away. Nothing else.
Jan Didden
Understood and agreed, but... I can clip a standard 30W tube amp and hear it easily. I can do the same with my amp (designed specifically for non-blocking) and not hear it at all until the clipping gets gross.
Likewise, my phono preamp has very high overload margins in each stage. With many records, I can't really distinguish it in a blind test from other good stages with the same frequency response and reasonably low distortion. But use an MC cartridge and play an older record in lousier shape and...
I think it was David Rich who wrote an article about this. He pointed out that, no matter the "audiophile" wisdom, there were components of totally opposite design philosophies which nonetheless were highly regarded in the high end community.
Sociology often triumphs reality.😀
Likewise, my phono preamp has very high overload margins in each stage. With many records, I can't really distinguish it in a blind test from other good stages with the same frequency response and reasonably low distortion. But use an MC cartridge and play an older record in lousier shape and...
I think it was David Rich who wrote an article about this. He pointed out that, no matter the "audiophile" wisdom, there were components of totally opposite design philosophies which nonetheless were highly regarded in the high end community.
Sociology often triumphs reality.😀
It would seem to me that an amp that measures (not just THD) really well produces a sound that doesn't necessarily satisfy those who go in for analytical listening as there isn't actually anything to hear with such amps.
The only thing to do for such people is to give the amp some kind of sound and this is where subjective choices come into play. The sucessful designer is then one whose subjective tastes are in tune with what others want. I don't have a problem with this.
The only thing to do for such people is to give the amp some kind of sound and this is where subjective choices come into play. The sucessful designer is then one whose subjective tastes are in tune with what others want. I don't have a problem with this.
fredex said:
That's an interesting speculation. I think it may be true in some cases, but can not be taken as a good generalization nor a view of the majority.
There are certainly those who seek to use what I call "complementary colorations" in order to achieve what one might term a "balanced presentation", such things rarely result in a system that really "works" with a wide range of recordings or subject matter...
Knowledgable, sophisticated audiophiles work hard to limit the colorations to the point where they can be added in selectively, if desired. Point being that the ultimate "idea" if there is one, is to hear the original source for better or for worse.
Interestingly (I think) that when one truly gets to a system that is reasonably good at this, one finds that still some recordings are not satisfactory... and indeed some are not... yet when one peels the proverbial onion a bit more, one often finds that recordings that were formerly not so satisfactory suddenly "reveal themselves" in unexpected ways.
Two examples for the latter that are relatively easy to convey here in words are old live two mic audience recordings and a CD of George Bolet that sounds like it was recorded down a long hall... In the former case if the soundstage can be recreated sufficiently well, the performance "floats" while the negatives can be disregarded adequately. If it's not quite right, or there are some reproduction artifacts, the whole things becomes quickly unlistenable.
I'm not talking about soft sounding mushy amps that gloss over things either.
In the case of the Bolet CD a small variation in frequency response, and perhaps (heresy here) inter driver phase causes the piano to receed to far back making the recording sound like carp... So on my very nice Acoustat ESLs that recording sounds not so great, in my view due to the ESL's freq resp, whereas on my horn system which is very very flat without EQ, it sounds just fine...
So, is that recording good or bad? Are the Acoustats that are better (imho) than maybe 95% of all good speakers not good enough?
Are your speakers better than those Acoustats?
In how many areas? All?
Are they in a better room, set up optimally?
How would you or anyone else (DBT or not) know if or what in their system was a weak link, confounding, or masking??
My view is that the goal is to have music (or spoken word) in the room, not coming out of speakers... invisible speakers.
So, there are basically two ways to do that - one is to make everything sound the same, the other way is to make everything sound "right" and hope that most recordings are listenable, and the ones that are not are not due to something in the so-called "right'" system.
Take a Blowtorch, hook it to ur superextraultralowdistortium amplifier and what do you have, or how do you know what you have...?
Fact is that no matter what you measure, design, build, test, optimize, that reproducing sound in a room still involves human sensibilities, involves what we call "art" and as of yet is not reducible to a scientific or mathematical certainty. In fact the opposite seems true, as time has gone on, "distortions" are reduced by maybe 3 orders of magnitide or better since say 1969, yet designers and engineers are still trying for more, and arguing all the time over the threshold and the detail! As here.
Let's be clear, science and engineering are the main tools at hand, but in the end it has to please the human psyche in order to be even useful.
_-_-bear
I'm very sensitive to that and it's important to me, but IME, it has nothing to do with the electronics (unless there's an interchannel frequency response difference). It's a matter of polar pattern, diffraction, and the room itself. My speakers are very good at this, but that remains true whether I use my nice tube amps or a cheap POS transistorized receiver.
You'd think that if electronics could alter that, it would be easy to pick out in a blind test, n'est-ce pas?
Yes.
However that blind test would only be valid for the test as it was done, not generalizable without some rather extreme controls put in place...
...I don't think that it is terribly difficult to hear an awful lot of things once you get the speaker distortions down to a manageable level...
But that's only my personal opinion based upon nothing substantive other than personal experience... as always your experience may differ.
But just for the record, the number of systems that I have ever heard that meet the above rather nebulous criterion I can count on the fingers of one hand. That's going back too many decades and for way too many systems of all types, sizes and prices.
_-_-bear
However that blind test would only be valid for the test as it was done, not generalizable without some rather extreme controls put in place...
...I don't think that it is terribly difficult to hear an awful lot of things once you get the speaker distortions down to a manageable level...
But that's only my personal opinion based upon nothing substantive other than personal experience... as always your experience may differ.
But just for the record, the number of systems that I have ever heard that meet the above rather nebulous criterion I can count on the fingers of one hand. That's going back too many decades and for way too many systems of all types, sizes and prices.
_-_-bear
SY said:
IME it may depend on electronics. I have heard several power amplifers that tended to drag the sound and localization into the speakers (physical position). The comparison to another power amps that filled the whole space and let the speakers "disappear" was clear. However, it had nothing to do with crosstalk and frequency response, or step response, or distortion.
Bear and SY,
I very much agree with most of your posts above.
As for the 'lack of analytics' in a transparent amp, it is always my goal to have the amp as transparent as possible, *without* colorations of its own. You should not say 'I can't here anything in that amp', no, you can hear the music and only the music!
Some people like a bit of coloration, and consequently, they would probably prefer a different amp than I would. And yes I agree that amps can sound different. If they have diffferent output impedances (both magnitude and phase over frequency), different clipping behaviour, different power supply characteristics and probably a few more different attributes, they can sound different, although it also depends on how the speaker system interacts with them. Same with boutique cables.
But I also feel that well engineered amps designed with the goal to be as transparent as possible cannot be discerned in a controlled blind test.
You are right that the most gross differences come from speakers and especially the music itself. The CD and its followers gave us a technical medium that is, as a medium, far superior to the LP and pick-up. Yet, many LP's sound much better than CD. Why? Because the recording stinks. Take the trouble to record a good LP to CD. Overwhelmingly, you will not be able to hear a difference between the two.
This whole interaction between many factors is also the reason why anecdotal, sighted tests are not much value for anyone except the person doing the test. HE (m/f) may be satisfied that he made a good choice, but for others, that have different speakers, listen to different music, have different preferences, that choice may be just the wrong one.
Controlled blind tests are not for determining one's preferred component. That preference is personal, and one man's preference may be another man's abhorrence. Controlled blind tests are to find out if there is a difference in sound between components. But it passes no judgement. Even if two amps would be found to sound clearly different, there may be many that prefer one and many that prefer the other.
Jan Didden
I very much agree with most of your posts above.
As for the 'lack of analytics' in a transparent amp, it is always my goal to have the amp as transparent as possible, *without* colorations of its own. You should not say 'I can't here anything in that amp', no, you can hear the music and only the music!
Some people like a bit of coloration, and consequently, they would probably prefer a different amp than I would. And yes I agree that amps can sound different. If they have diffferent output impedances (both magnitude and phase over frequency), different clipping behaviour, different power supply characteristics and probably a few more different attributes, they can sound different, although it also depends on how the speaker system interacts with them. Same with boutique cables.
But I also feel that well engineered amps designed with the goal to be as transparent as possible cannot be discerned in a controlled blind test.
You are right that the most gross differences come from speakers and especially the music itself. The CD and its followers gave us a technical medium that is, as a medium, far superior to the LP and pick-up. Yet, many LP's sound much better than CD. Why? Because the recording stinks. Take the trouble to record a good LP to CD. Overwhelmingly, you will not be able to hear a difference between the two.
This whole interaction between many factors is also the reason why anecdotal, sighted tests are not much value for anyone except the person doing the test. HE (m/f) may be satisfied that he made a good choice, but for others, that have different speakers, listen to different music, have different preferences, that choice may be just the wrong one.
Controlled blind tests are not for determining one's preferred component. That preference is personal, and one man's preference may be another man's abhorrence. Controlled blind tests are to find out if there is a difference in sound between components. But it passes no judgement. Even if two amps would be found to sound clearly different, there may be many that prefer one and many that prefer the other.
Jan Didden
Some very good points made here. My goal is gear that has no sound of its own, but as bear might be suggesting how will I know when or if I get there? I can only judge it by comparing it with other gear. Before you say what about comparing it with live sounds, I do not know if the recording I am listening to is a natural sounding recording.
I set this goal as I believe if it is reached I will not hear the gear thus all that will be left is music, glorious music which is why I started all this years ago............... yeah I know it's just a dream.
I set this goal as I believe if it is reached I will not hear the gear thus all that will be left is music, glorious music which is why I started all this years ago............... yeah I know it's just a dream.
fredex said:
Good points. I agree that comparing it to live sounds is not a viable option in most cases. There are a few ways you can make sure that your gear is 'transparent'.
One is to compare it with other gear that is different in concept, different in execution, etc. If both sound good to your ears, AND if both show no differences in controlled tests, there is big chance (but no absolute certainty) that they are transparent.
Another option is to look at what people can reasonably hear in terms of equipment faults, and design your equipment for, say, an order of magnitude below that.
Now before you all fall over me again, I am not saying that the only equipment you should like is the equipment designed like stated above. My goal is to design transparent equipment as well as I can. But that doesn't mean everybody prefers such equipment, far from it. I can well imagine that a small change to an amp may measureably make it worse, yet someone may prefer the new version to the old. Someone may prefer the warm sound of an amp with a rich, monotonous distortion spectrum, others may feel a transparent amp is too 'clinical'.
But you must stay critical. If you go to audio shows, you too often hear outright bad sound but with the audience salivating because it's supposed to be the latest & greatest....
Edit: And BTW, life without dreams would be pretty dismal anyway 😉
Jan Didden
At least as those tests are currently structured AND assuming that no clipping is involved. I think that there may be other controlled ways to, for example, distinguish a transparent triode amp from its solid state equivalent, but I'm perfectly willing to admit that it might be illusory, and if my test ideas would ever be implemented, I'd be willing to change my mind if the results came up null. Langmuir's lessons should not be lost on audio designers.
Nonetheless, the fact that with current controlled tests, no listener has ever been able to tell one low distortion, low source Z, flat frequency response amp from another tells me that whatever differences are there are pretty minor, especially compared with easy-to-distinguish changes in sound from different speakers or room acoustics or harder-to-distinguish but detectable minor changes in frequency response or level.
Ok, lets have some fun here. The picture below is a multitone measurement from an amp I'm working on.
The large yellow traces are the test frequencies, 31 total at the same level according to the ISO standard. This signal is used as it has a much closer correspondence to music that single or a few tones. The load is a resistive 8 ohms.
The top line is the freq response derived from all the frequencies in the output signal.
The cyan curve at the bottom shows the frequencies in the output signal which are not in the imput signal. Can be considered as all harmonic and non-harmonic products due to amplifier non-linearities.
The blue curve at the bottom is the output noise, basically everything except the input- and distortion products.
Question: where does this amp need work to make it better, and why?
Jan Didden
PS SY your post above is spot-on of course.
The large yellow traces are the test frequencies, 31 total at the same level according to the ISO standard. This signal is used as it has a much closer correspondence to music that single or a few tones. The load is a resistive 8 ohms.
The top line is the freq response derived from all the frequencies in the output signal.
The cyan curve at the bottom shows the frequencies in the output signal which are not in the imput signal. Can be considered as all harmonic and non-harmonic products due to amplifier non-linearities.
The blue curve at the bottom is the output noise, basically everything except the input- and distortion products.
Question: where does this amp need work to make it better, and why?
Jan Didden
PS SY your post above is spot-on of course.
Attachments
Power supply. Looks like there's not only some noise from it, but also a bit of signal modulation.
What's the window you use for the FFT?
What's the window you use for the FFT?
Try a harder one next time.
Then again, not being a degreed EE or even having any engineering training, what the heck do I know?
Then again, not being a degreed EE or even having any engineering training, what the heck do I know?
Never forget back EMF,and how that affects the micro-distortion characteristics. How this interacts with the 'delta' of the distortion curve on the loading of a cable, driver, crossover and feedback system on the given amp, and as well, the implementation of the output section itself. All of the complex impedance pathways that can have a high delta of 'change' under the transient load of Back EMF.
This, as a point of analysis, due to how the ear hears.
The minimum it can be seen as, (for visualization and comparison purposes) is as a car with a ridiculously bad suspension driving at breakneck speed down a washboard road. (For those who don't know this particular (north)Americanism, a washboard road is a dirt road that has deteriorated due to an area near the stopping/slowing points -due to high levels of vehicle braking in those road areas.)
It guarantees that peak signal conditions, which is all that the ear hears and works with..will be exacerbated with regards to associated distortions - to the highest degree possible and be the predominant point that is 'worked' (electrically) in the system.
Sine wave analysis and/or standard electronics distortion measurement techniques are 'as useless as teats on a boar' in this situation. They will not show the percentage value of that portion of the signal that has been affected by the complex impedance variations. They will show it as a percentage value of the signal as a whole, which is fundamentally wrong and irrelevant to attempting to correlate measurements to what we are hearing.
Please use correct weighting for the first time in your lives.
If you have to think, and design that test- so be it.
Bu the first step is understanding the actual question at hand.
And this is it.
As reality tends to go..the situation is that then the mirror of that 'point of manipulation' of the system is the output section..then..in a linear PS amplifier design, the other side of the 'lever/fulcrum' (that is the amplifier output section)..is the circuitry and PS that are the other parts of the amplifier.
How they handle transient loading/draw under all possible loading considerations and conditions.....is all that counts.
The rest of the measurements are nearly irrelevant, with respects to correlation to how the ear hears.
if one thinks about that clearly for a few seconds, then it is entirely possible to understand how the sound of a fuse, a transformer, a power cable and IEC connector can 'come through' and an audiophile to actually be able to understand and hear a change in those components.
As transient loading stresses them to the max and their true colors with respects to 'change in loading through a transient' in loading ..will come through clearly.
This then clarifies the point of, ohh ...(pick one, it's like shooting fish in a barrel) for example... tempco ppm in resistors as being eminently hearable consideration.
Then the rest of it will become clear.
Then what will you argue about? Something else, I'm sure.
This, as a point of analysis, due to how the ear hears.
The minimum it can be seen as, (for visualization and comparison purposes) is as a car with a ridiculously bad suspension driving at breakneck speed down a washboard road. (For those who don't know this particular (north)Americanism, a washboard road is a dirt road that has deteriorated due to an area near the stopping/slowing points -due to high levels of vehicle braking in those road areas.)
It guarantees that peak signal conditions, which is all that the ear hears and works with..will be exacerbated with regards to associated distortions - to the highest degree possible and be the predominant point that is 'worked' (electrically) in the system.
Sine wave analysis and/or standard electronics distortion measurement techniques are 'as useless as teats on a boar' in this situation. They will not show the percentage value of that portion of the signal that has been affected by the complex impedance variations. They will show it as a percentage value of the signal as a whole, which is fundamentally wrong and irrelevant to attempting to correlate measurements to what we are hearing.
Please use correct weighting for the first time in your lives.
If you have to think, and design that test- so be it.
Bu the first step is understanding the actual question at hand.
And this is it.
As reality tends to go..the situation is that then the mirror of that 'point of manipulation' of the system is the output section..then..in a linear PS amplifier design, the other side of the 'lever/fulcrum' (that is the amplifier output section)..is the circuitry and PS that are the other parts of the amplifier.
How they handle transient loading/draw under all possible loading considerations and conditions.....is all that counts.
The rest of the measurements are nearly irrelevant, with respects to correlation to how the ear hears.
if one thinks about that clearly for a few seconds, then it is entirely possible to understand how the sound of a fuse, a transformer, a power cable and IEC connector can 'come through' and an audiophile to actually be able to understand and hear a change in those components.
As transient loading stresses them to the max and their true colors with respects to 'change in loading through a transient' in loading ..will come through clearly.
This then clarifies the point of, ohh ...(pick one, it's like shooting fish in a barrel) for example... tempco ppm in resistors as being eminently hearable consideration.
Then the rest of it will become clear.
Then what will you argue about? Something else, I'm sure.
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