Audio Science: Does it explain everything about how something sounds?
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Regarding timing, I think the following article by Martin Colloms is excellent:
http://www.stereophile.com/reference/23/
Since that time, 1992, digital has made a lot of progress, and the Berkeley Alpha DAC 2 is the first one of my five CD players/DACs so far that gets rhythm & timing right (if that's what you mean, Ack), but his main points still stand -- and they extend to much more than just digital playback.
http://www.stereophile.com/reference/23/
Since that time, 1992, digital has made a lot of progress, and the Berkeley Alpha DAC 2 is the first one of my five CD players/DACs so far that gets rhythm & timing right (if that's what you mean, Ack), but his main points still stand -- and they extend to much more than just digital playback.
That's the conclusion I came to awhile ago.
Unfortunately, given the myriad of past threads similar to this one, sad but true.
While I have never blocked a poster on any site, no matter how useless they are, I am curious where the 'Ignore' option is here. I am sure it is right in front of me, and as soon as I post this I will see it.
Go to 'profile' of that poster and choose option 'add to ignore list'.
Thanks for a reasonable post Orb. Some comments below.
Notice how after two to three minutes, it has reached its optimal performance. It actually performs slightly worse as it keeps warming up! Fortunately all of these are at very low distortion figures (see the vertical scale on the left).
Now, this is one of his designs and there are thousands of amplifier designs out there. No doubt some are incompetent design too and may have poor thermal tracking and are optimized for to work best at higher temps. It is hard to say. What I can say is what I said above. If an amp after a couple of minutes doesn't sound excellent, it is not an excellent design in my book.
What this says is that it is routinely expectation bias that an amp that has warmed up for an hour or more is sounding better in an obvious way. To only way to prove it is to take away that expectation/knowledge of the warm up time and see if the observation is resilient. As you correctly note, such a test has not bee run. Given that, I have to rely on my experience of design factors and listening abilities of audiophiles to say that vast majority of people who think their equipment is sounding noticeably better after multi-hour warm up are likely mistaken.
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Thermal tracking is one of the key designs in amplifiers. In my book though, a good design reaches near optimal if not fully optimal point in 2-3 minutes, not hours. Even if optimal performance is reached in 2-3 hours, audibly the amp better sound excellent after a couple of minutes.
Let's agree that Doug Self is one of those knowledgeable engineers when it comes to amplifier design. In his book, he has a huge chapter on thermal tracking and measurements of THD over time. Here is one graph from it:
Notice how after two to three minutes, it has reached its optimal performance. It actually performs slightly worse as it keeps warming up! Fortunately all of these are at very low distortion figures (see the vertical scale on the left).
Now, this is one of his designs and there are thousands of amplifier designs out there. No doubt some are incompetent design too and may have poor thermal tracking and are optimized for to work best at higher temps. It is hard to say. What I can say is what I said above. If an amp after a couple of minutes doesn't sound excellent, it is not an excellent design in my book.
There is that. But there is also the opposite: namely the fact that vast majority of audiophiles are not sensitive to non-linear distortions. To wit, hardly anyone repeated my double blind ABX tests in the high-res thread. When I was at Microsoft, we tested audiophiles and their ability to hear non-linear distortions in compressed music was no better than general public which is to say, non-existent. There are some exceptions of course but vast majority are not such.
What this says is that it is routinely expectation bias that an amp that has warmed up for an hour or more is sounding better in an obvious way. To only way to prove it is to take away that expectation/knowledge of the warm up time and see if the observation is resilient. As you correctly note, such a test has not bee run. Given that, I have to rely on my experience of design factors and listening abilities of audiophiles to say that vast majority of people who think their equipment is sounding noticeably better after multi-hour warm up are likely mistaken.
Despite my higher acuity in being able to hear non-linear distortions, my general position is that until I have positive confirmation of something in a controlled tests, I don't put value on it. In this regard, I am perfectly happy with an amp after it has warmed up for a few minutes
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Digital has made a lot of progress indeed... The Berkeley does well, but yet once more, I had another breakthrough yesterday when comparing it to analog... will post on my system thread, but in brief, I played back to back the Mahler 2nd on Philips Digital (BSO/Owaza) - first the CD, then the LP (which I acquired back in June and hadn't played yet) - and the LP of the same 16 bit digital recording sounds a lot more resolving, natural, and with excellent timing that the Berkeley cannot match... and since the recording is the same 16-bit redbook, the only material difference is the analog chain, which means the analog section in the Berkeley isn't close and/or there is too much jitter still (and my transport is extremely-low jitter)...
So let me know what you disagreed with, earlier...
Very interesting! Yet if the jitter in the Berkeley DAC is still too high (incoming and/or corrected), which magical DAC did they use almost 30 years ago when they converted for LP? Or would a digital tape rather than a CD have been less prone to jitter? In any case, it is good to hear yet another instance where it turns out that 16-bit/44.1 kHz digital has inherently much more potential than we had thought for decades -- I knew it, and on a technical level I am not surprised. In fact, this is one of those instances where the posts of Amir, Esldude and other 'technical' folks have greatly helped my understanding.
Mainly the above-20-kHz part. But perhaps you're right, and the future will give us surprises there -- yet I don't hold my breath.
David, there continues to be substantial errors in your explanation of this situation and frankly, I am getting tired of correcting it. So let's assume there is appearance of bias and move on to show that such an appearance has generated faulty research. Show that, and we can have an educated discussion. Otherwise, if you want us to dismiss the research based on appearance of bias alone, we need to dismiss a boat load of your posts too due to what is in your signature. Surely you don't want to go there.
So please go on and show what test results you have that is published, peer reviewed and from luminaries in the industry that contradict the research as presented. Happy to take data from anyone you might list that also has appearance of bias.
I think it's just words. I think anyone could put together a similar piece about anything they feel experienced in or an 'expert' on, but which, when it comes down to it, is just about talking about one's own subjective experiences. Food, wine, travel, film, TV, literature are all the same. Does tea taste different if you use an electric kettle or a gas ring? 'Science' might suggest that it doesn't matter, but Martin has tasted tea on five continents and can write six pages on how electric tea tastes good at first: bold, exciting, dynamic. But after a few cups he realises that it's a superficial, fragile attraction. Gas tea, on the other hand, is more understated, but more natural. In the long run the gas tea drinker gets more from his drink. etc. etc.
It's just basic psychological self-delusion expanded into extremely large volumes of words.
Hehe, I won't get into a futile debate with you on the subject. Believe what you want. I have my experiences, and have even reached a consensus on some of them with others who heard the same things in the same listening sessions -- it was so glaringly obvious that there wasn't even a debate.
Yes, that would be interesting. It was quite revealing when spectral analyses of early hybrid SACD/CDs showed that the SACD layer was mastered differently -- and if the master was not just different but better, no wonder it sounded better than the CD layer! In general I have heard many times from many people that the difference in quality between SACD and corresponding CD can simply be ascribed to better mastering of the former (and sometimes it's the CD that apparently sounds better!).
In other words, it has nothing to do with the 'better' medium. I am glad I stayed out of the silly format wars, and now SACD is obsolete anyway. Good that I didn't bother in the first place.
Your posts are not evaluated by computers AJ. They are evaluated by people. And those people don't follow logic 101. People follow a conversation and like to learn something from it and pure questioning of the other side doesn't do that. BTW you can prove a negative (see https://www.psychologytoday.com/blog/believing-bull/201109/you-can-prove-negative). We do that all the time in psychoacoustics by showing how a distortion measurement falls below the threshold of audibility and hence is "inaudible."
So I am going to join others in asking you to think about your posts and make sure they contribute some data or insight to the conversation. Otherwise the accusation of trolling sticks. Look at my answer to Orb how to you can insert information while holding the position you are holding (i.e. attempting to prove a negative).
Unfortunately, I am not. Mastering is always a parameter, but consider this... I was going to give more details on my system thread, but another interesting piece of data is that on Madfloyd's system, with the Lampizator back then, the same CD (which I brought over) almost touched the sound of my analog now (and exceeded it in some aspects); the fact the same CD from his digital was so much better on his system than mine and close to my analog now, mostly eliminates the mastering parameter and strengthens my point that the Alpha isn't as good as the Lampi was in that respect, or my analog.
What jumped out at me first in Ian's system was the resolution; I had the same reaction yesterday from my analog. For example, the 2nd features a harp - it's somewhat muted from my Berkeley, but is there in all its glory in his system and my analog now. Where I feel the CD from his Lampi still lacks compared to my analog - and where perhaps mastering is at play - is in the Finale, with the massive chorus, orchestra and organ... whereas we heard a loud but constricted and distorted [at times] chorus (as from my Alpha) and great, deep thundering organ in his, I hear a loud, wide, deep and unsaturated chorus from the LP, very clear bass notes, but certainly no deep bass [due to the speakers] to make the organ sound anywhere near as impressive as on his Magicos (no surprise there).
Yes, Redbook has a lot of potential, but the bandwidth limitation is a serious issue:
When you get a chance, do read the research I posted from 2012, I think it is fascinating what the ear can hear that you don't readily perceive. I was turned on to this high-frequency aspect of our hearing about 15-20 years ago, when I first read the HDCD patent (a sort of bible in the digital domain, if you will). The other important point made by atmasphere in this thread, and myself and others in the past is that, wide bandwidth ensures phase linearities in the audible range. I am actually so glad to be seeing so many wide-bandwidth designs the last decade, including output-transformer-coupled tube designs.
I've gathered that much.
Although I wouldn't ascribe this to the entire audience. Clearly there are a few that do and aren't disagreeing. But obviously I've upset them a lot less.
Now, now, let's not go there again. See, we both continue to learn from the man.
Point noted and perhaps I should have done some digging as you have above. But as I have stated several times, the whole amp warm up/physical/measured explanation thing flies completely contrary to the thread premise! Forgive me for not going the extra mile as you did.
I'm still hoping Peter or someone gives an example of some sound that is designed, engineered and manufactured into audiophile products, that is completely unknown to audio science.
cheesrs,
AJ
Thanks for a reasonable post Orb. Some comments below.
Thermal tracking is one of the key designs in amplifiers. In my book though, a good design reaches near optimal if not fully optimal point in 2-3 minutes, not hours. Even if optimal performance is reached in 2-3 hours, audibly the amp better sound excellent after a couple of minutes.
Let's agree that Doug Self is one of those knowledgeable engineers when it comes to amplifier design. In his book, he has a huge chapter on thermal tracking and measurements of THD over time. Here is one graph from it:
Notice how after two to three minutes, it has reached its optimal performance. It actually performs slightly worse as it keeps warming up! Fortunately all of these are at very low distortion figures (see the vertical scale on the left).
Now, this is one of his designs and there are thousands of amplifier designs out there. No doubt some are incompetent design too and may have poor thermal tracking and are optimized for to work best at higher temps. It is hard to say. What I can say is what I said above. If an amp after a couple of minutes doesn't sound excellent, it is not an excellent design in my book.
There is that. But there is also the opposite: namely the fact that vast majority of audiophiles are not sensitive to non-linear distortions. To wit, hardly anyone repeated my double blind ABX tests in the high-res thread. When I was at Microsoft, we tested audiophiles and their ability to hear non-linear distortions in compressed music was no better than general public which is to say, non-existent. There are some exceptions of course but vast majority are not such.
What this says is that it is routinely expectation bias that an amp that has warmed up for an hour or more is sounding better in an obvious way. To only way to prove it is to take away that expectation/knowledge of the warm up time and see if the observation is resilient. As you correctly note, such a test has not bee run. Given that, I have to rely on my experience of design factors and listening abilities of audiophiles to say that vast majority of people who think their equipment is sounding noticeably better after multi-hour warm up are likely mistaken.
Despite my higher acuity in being able to hear non-linear distortions, my general position is that until I have positive confirmation of something in a controlled tests, I don't put value on it. In this regard, I am perfectly happy with an amp after it has warmed up for a few minutes
Thanks Amir and always enjoy the data you present.
Yeah no disagreement with Doug Self but does he show it all the way up to 30min-45minutes (anecdotally improvements with some of these amps I am talking about as shown is the first 5 minutes and then not much until the period we all have been mentioning), but I think you will also appreciate engineers such as Nelson Pass, also we have magazine measurements that show cold start-up and then usually 20min-30minutes later.
One key point to these measurements (and we all can say THD is going to be low) is it is showing how an amplifier behaviour changes (unfortunately not up to 30-45 minute mark in the chart), it will also be dependant upon topology,transistors used, bias,etc, why I IMO I tend to notice it more with Class A amps rather than less biased AB designs (although strangely the Dartzeel 8550 does anecdotally seem to fall into needing a lot of time *shrug*).
That said I am not saying it is THD we are hearing, but it is used an indicator of behaviour where other measurements should be potentially used to investigate further (but I agree it will not happen because in the scheme of things it is not going to cause panic and hysteria in the world
), and importantly there is a correlation between the amp improving even with these small measurements and subjective listening (caveat yeah depends upon the amplifier, not a dbt ABX, based on various engineers who each have their own design topology and internal component preferences, etc).In fact it has been mentioned by many engineers THD is not the best measurement in terms of how an amplifier sounds, but we can use it to see behaviour-trend in this example even if not ideal.
Regarding your comment about expectation bias, IMO that breaks down because it is not consistent across all amplifiers, the anecdotal comments usually have a greater predication towards high biased Class A amplifiers rather than efficient AB designs or hybrid designs or Class D, that said there are also SS examples involved with AB but most listeners will mention it is not heard for all amps they have experienced (and I agree it is not in my experience, some great straight off, some just 5 minutes, quite a few around 30-45 mins).
Now most listeners may know about the different classes but it is asking a lot to link expectation bias being so selective when users do not necessarily understand the biasing scheme and details on topology/transistor type operation or why they would associate it more with Class A, and with some but not all Class AB, and rarely Class D or hybrids (such as the Devialet that in my experience is far more linear in behaviour from cold start to warm-up).
Also another aspect questioning expectation bias, most who experience this kind of very subtle improvement also comment about a perceived loudness shift (I doubt it is actual but who knows we are talking subtle changes), so a specific perceived variable rather than vague its just better/worst; yeah appreciate I am reducing this to a one line sentence.
And now we come to the actual relevance of small values that change and why I think it is interesting to raise your experience with the hirez ABX, even you must agree that those who disagree with you passing this legitimately do so because they state measurement differences are so small and meaningless, so here you are arguing from a point of view of a successful audibility test that in theory has measurement values too small.
It is like when you debate with those same people about jitter, and how low those spurs are in context of signal is their defence.
So yeah I agree THD is not necessarily what is being picked up, but we do see a correlation between it and what engineers say and listeners' experience, even if it is for the first 5 minutes as what Doug shows, and tbh I think that model expands beyond that based upon what I have just raised and what other engineers say with their own design/transistor selection preferences.
BTW coming back to small measurements (which some are using as part of their reasoning on differences being meaningless), any idea which ones would correlate to your experience in passing the hirez vs CD and what their measurement values were and the changes/differences?
It does link nicely into aspects of this debate.
Oh and yeah like you say and quite a few others including audiophiles, in the scheme of things cold start to warm-up is not much of an audiophile issue as either turn it on or don't
But it did fit in showing this to some others in this thread, just like my comments about warehouse cold temperature aluminium speakers and how they subtly change to when they are room temp (Magico is a good example comparing their older wood based to the newer aluminium).
The reason I am focusing more on the 5 minutes and 30min-45min mark rather than hours and days is because this has engineering measurements and is a known entity with a perception variable linked in many cases (loudness shift) - I say many because it would be wrong to say for all out there.
But this post should be taken in context with the recent other ones I posted - not directed at you Amir, but I do think its focus and context will get skewed by some
Thanks
Orb
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