Sound Quality Vs. Measurements

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A DIY forum is supposed to be scientific? Wow! Next thing we learn is that posts here should be counted as papers. Please, give us a break. This forum is supposed to fun, and anything above that, while desirable is simply extra profit.

I don't think anybody implied that at all. It's just that many here - and I'm one of them - really want to know what's going on, how can I understand something, how can I make better stuff by continually learning.
If someone says that he changed opamp A for opamp B and the sound opened up, I want to know WHY so I can build better preamps. That's my hobby, that's how I have fun.

The problem is, how do I know that changing A for B REALLY opened up the sound? Did it really? Was it just perception with all it's traps or did the guy make an effort to test it ears only?
So naturally, that's the first question I would ask. Anybody who would be serious in this as I am would understand the question completely and try to describe exactly what he did, how he tested it, and why he decided that the effect is real.

Now others, when I ask that question, act insulted. That is a sure sign that they do not understand and/or appreciate why I ask the question. A safe conclusion is then that they did not really do any serious testing; and I would tend to ignore the 'result'. Hell, if someone immediately acts defensive and insulted, you don't even know if he really changed the two opamps at all or that it only happened in his/her imagination. Maybe he doesn't even own those opamps but just likes to post something that attracts attention.
I'm not saying that is the case often or sometimes or with specific persons, I just want to say that we have no way to know what the situation is at all.

If someone starts to describe all sorts of details of his tests, there's a better change that it actually happened and that it was done seriously. No guarantee, but a lot more likely.

Jan
 
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And, pray tell, what scientific value have you contributed? A link to a test I personally consider to be next to worthless in objective terms? Do you REALLY think some of us haven't done things like that 35+ years ago, and that we speak of uselessness only because we have found such tests to be just that?
If you personally consider trying to actually determine what's audible by using testing and facts, then this ends up being a complete waste of bandwidth wankfest. Yes, I really do think people have half-heartedly attempted to do some testing, but frankly have done it incorrectly..most likely on purpose, in order to reinforce their flawed ideology, in the same vein as climate skeptics do.

If you want to discover new fields, buy tons of measuring gear, sit back and measure for days on end.
Maybe I do, maybe I don't. The difference is, I don't drop my opinion on the masses with all the certainty of round-earth theory, while at the same time, failing - or even outright refusing to offer any type of real data to back it up. I'm making a plea for information, something that in it's current sorely unrepresented state seems to not only be acceptable, but glorified and touted as correct.

A DIY forum is supposed to be scientific? Wow! Next thing we learn is that posts here should be counted as papers. Please, give us a break. This forum is supposed to fun, and anything above that, while desirable is simply extra profit.
It's fun as long as it's fun, but you can't discount the fact that some of us can not have any fun or learn anything as long as the disdain for testing methods and the proliferation of false claims continue. I don't find reading 20,000 posts of which 80% are garbage claims to be fun.

I for example like to ask a question here and there and benefit from the collective exprience of forum members. The answers will generally include some statistical data, some hard science and lots of experience from those who have been there and done that.

That's the problem, as long as the entire thread is just a competition of who can have the worst ideas, then the "experience" isn't worth learning from, any more than someone's "experience" of the ghost of captain Ahab would be considered a learning opportunity.
 
Starting to sound like JC.

Perhaps so, but it still remains a fact.

Group testing, ABX testing, small panels, large panels, all that was not only being done then, but we did it ourselves as well as reading about it in the mags.

We could, because those were the heydays of audio, many people were interested, and even organizing mass events almost guaranteed more visitors than the rented hall or theather could handle.

The last such event I went to in 1990 or 1992 filled a 600 seat theatre to the point where people were standing or sitting between rows of seats, aling the side walls, etc.

In those days, when somebody bought something really new, a new TT with a new cartridge, pramp, amp, integrated or even a receiver, it was quite normal to invite friends over for a listening session. From a group of say 20 people, you were guaranteed that at least 12 would turn up no matter what. It was not only a custom among the dedicated, it was a true social event along with an audio event. Rare were the weeks when nothing was up. Especially during automn, winter and early spring.
 
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In those days, when somebody bought something really new, a new TT with a new cartridge, pramp, amp, integrated or even a receiver, it was quite normal to invite friends over for a listening session. From a group of say 20 people, you were guaranteed that at least 12 would turn up no matter what. It was not only a custom among the dedicated, it was a true social event along with an audio event. Rare were the weeks when nothing was up. Especially during automn, winter and early spring.

As you said been there done that what a joke listening to the latest crap from Carver boosted with some over the top psuedo-scientific name. Yes turn the effect up to "11" and it was obvious to everyone in the room.
 
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Dyna, I can build amplifiers below 0.001% harmonic distortion with high slew rate and low noise. You keep opinion that everything sounds same, I do not care. I just see what you really know.

I've never said "everything" sounds the same, I'm merely suggesting that a person who makes a claim about audible differences in a piece of gear that an oscilloscope has already deemed linear to the threshold of audibility, have the courtesy to be willing to demonstrate such superhuman feats of hearing.

Failing that (which has been a complete and utter farce within context) at least preface your emotion-based observations as such, rather than continuing to bandy manufactured, self fulfilling wish-thinking around as if it was verifiable fact.

If a person makes a claim to an audience, such as a forum filled with acoustic / electrical engineers, you should probably be prepared to offer something substantive, rather than just get mad at those who ask, or attack testing methodologies in what's probably the most malleable test of auditory ability in existence.
 
I don't think anybody implied that at all. It's just that many here - and I'm one of them - really want to know what's going on, how can I understand something, how can I make better stuff by continually learning.
If someone says that he changed opamp A for opamp B and the sound opened up, I want to know WHY so I can build better preamps. That's my hobby, that's how I have fun.

The problem is, how do I know that changing A for B REALLY opened up the sound? Did it really? Was it just perception with all it's traps or did the guy make an effort to test it ears only?

So naturally, that's the first question I would ask. Anybody who would be serious in this as I am would understand the question completely and try to describe exactly what he did, how he tested it, and why he decided that the effect is real.

Now others, when I ask that question, act insulted. That is a sure sign that they do not understand and/or appreciate why I ask the question. A safe conclusion is then that they did not really do any serious testing; and I would tend to ignore the 'result'. Hell, if someone immediately acts defensive and insulted, you don't even know if he really changed the two opamps at all or that it only happened in his/her imagination. Maybe he doesn't even own those opamps but just likes to post something that attracts attention.
I'm not saying that is the case often or sometimes or with specific persons, I just want to say that we have no way to know what the situation is at all.

If someone starts to describe all sorts of details of his tests, there's a better change that it actually happened and that it was done seriously. No guarantee, but a lot more likely.

Jan

One of the problems here that at times we are not discussiong any specfic question, it sort of drifts off, wandering here and there. The bes discussions here, in my mind, were when we were specific over some topic.

As for your mentioning the op amp A for B replacement, I agree completely. I also want to why, was it just a fluke, or is that generally applicable, should I or should I not stock up op amp X because it's really good, etc. Which is precisely why I withold from any comment on my own case and BB 22134 until I get hold of the service manual, which will at least give me some specific idea what have they done, where and how. I just noted that SOMETHING has obviously been done, and done right, according to the sound quality it delivers.

Next, we come to measurements. Once I know what I'm dealing with, I have some basis for testing. This means making an exct copy of what NAD did, but use it only as a simple line amp, and use the opportunity to test it against those I have and those I can borrow for testing. Then, I try my favorite moves on it, like adding a simple NPN-PNP small signal current gain stage, to see if I can perhaps improve it still a bit further. Obviously, measurements of each and every stage with notation. But of course, that's just my way of doing it, only one of many possible ways.

On group testing, where group is everything above one, i.e. me. The key problem there is establishing a constant and repeatable base line, meaning which speaker in which room. That is a bitch all unto itself, because who decides what's the reference speaker? What sounds supremely linear to me sounds a bit withdrawn to one friend, a bit lively to another, and so forth. Next, keeping the room the same across the board is simply not possible; if using five instead of two people, you have already changed the room acoustics, perhaps not by much, but sometimes giving one speaker an advantage over another hangs on very small differences, nuances.

Thankfully, I can "borrow" a properly sound treated recording studio of a decent size, but this does create a hassle, because I have to lug two 60 lbs boxes right across the city. But, it can be done if I really put my mind down to it.

Next, what's the reference we compare everything with? While strictly speaking we don't need one to compare amp A to amp B, it's tsill very handy to have one. This will require some hard negotiating, with much mention of family trees. And just when you get it, repeat the whole thing with cables. For referees, one should call upon one's two American friends, Smith and Wesson. And unfortunately, shooting an idiot audio voodoo believer is still illegal.

Because of all these complications, and many others I haven't even mentioned, I do shy away from group testing. All the more so since I've seen how things can dramatically change if you change the panel members. To answer Jan's question how do I know something really has changed, I usually take the device to the homes of a few trusted friends, whose opinion matters to me. They mostly hear it the way I hear it, but there have been instances when we differed in degree, sometimes they thought the differences to be smaller or larger than I did. I let them listen to it for at least 10 days, usually 14, because I believe our moods have much to do with what and how we hear something.

I repeat, that's just me, that's the general procedure I have arrived at over the years, but again, it's only one of many possible options.
 
As you said been there done that what a joke listening to the latest crap from Carver boosted with some over the top psuedo-scientific name. Yes turn the effect up to "11" and it was obvious to everyone in the room.

I never mentioned any names and FYI I never owned anything Carver ever did, either at Phase Linear, or any other time after that.

Personally, I never met Bob Carver, but through his interviews and text over the years, I had a negative attitude towards him. In part also because a friend of mine purchased his Phase Linear power amp. some 20-250 WPC job, which almost chocked on his AR 3a Improved speakers. Think of them what you will, but in their day those were very good speakers, although a known bitch to drive.
 
I've never said "everything" sounds the same, I'm merely suggesting that a person who makes a claim about audible differences in a piece of gear that an oscilloscope has already deemed linear to the threshold of audibility, have the courtesy to be willing to demonstrate such superhuman feats of hearing.

Failing that (which has been a complete and utter farce within context) at least preface your emotion-based observations as such, rather than continuing to bandy manufactured, self fulfilling wish-thinking around as if it was verifiable fact.

If a person makes a claim to an audience, such as a forum filled with acoustic / electrical engineers, you should probably be prepared to offer something substantive, rather than just get mad at those who ask, or attack testing methodologies in what's probably the most malleable test of auditory ability in existence.

Am I to understand from your first sentence above that you believe that if there is a difference in sound, it must show uo on an oscillocope?

What would be your reaction if according to the 'scope amp A did very well, but ended up being discarded in favor of amp B, whose 'scope readings were below, even well below, the 'scope readings of amp A?
 
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Which is precisely why I withold from any comment on my own case and BB 22134 until I get hold of the service manual, which will at least give me some specific idea what have they done, where and how. I just noted that SOMETHING has obviously been done, and done right, according to the sound quality it delivers.

.... which is exactly the wrong order. Don't look at the datasheet if you are ever serious about any controlled ears-only testing. It either sounds 'better' in a controlled ears-only test or it doesn't. The data sheet is irrelevant in this context and can only detract from you being unbiased.

Jan
 
What did he imply then, Jan?

Just to refresh your memory:

I've never said "everything" sounds the same, I'm merely suggesting that a person who makes a claim about audible differences in a piece of gear that an oscilloscope has already deemed linear to the threshold of audibility, have the courtesy to be willing to demonstrate such superhuman feats of hearing.

Looks like clear, simple, declarative sentences written in English.
 
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