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post #151 of 224 Old 12-30-2010, 10:13 AM
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Which leads me to the last point I'll make, of the many I feel; I've heard that often...the subjects in the DBTs are already "believers". That is, it's conducted for "the club" (of audiophile-haters), by "the club". So they come in with a predisposition that they don't think there's a difference. And I've heard the statistical sampling is too small for reliable conclusions, and the margins for error are as high as 80% sometimes.

Really? I've actually participated in a DBT (cables). First we listened sighted, before doing the DBT. Anyone who didn't hear a difference sighted did not continue to the DBT part of the test. What would be the point?

About 3/4 of us thought we could easily hear differences sighted, but none of us could tell them apart blind. It was an eye opener for me. You really should try it sometime, instead of just continually telling us why you "believe" DBT's aren't valid. Or at least learn what a DBT is.
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post #152 of 224 Old 12-30-2010, 11:16 AM
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Originally Posted by CDLehner View Post

Which leads me to the last point I'll make, of the many I feel; I've heard that often...the subjects in the DBTs are already "believers". That is, it's conducted for "the club" (of audiophile-haters), by "the club". So they come in with a predisposition that they don't think there's a difference. And I've heard the statistical sampling is too small for reliable conclusions, and the margins for error are as high as 80% sometimes.

Hi CDLehner.

It is true not all DBT audio tests are conducted properly, but that do not invalidate all of them.

MatrixHiFi people has put a good effort in those tests but unfortunately not all of them are strictly reliable, as Jose Almagro can testify.

But please do not come to wrong conclusione because (perhaps) you misunderstand these concepts: the test setup and the test conditions.

Some experts such as Sean Olive (AES member, BTW) among others have published peer reviewed scientific papers regarding this subject. I repeat, peer reviewed. And many conclusions have came up from those tests.

Moreover, AFAIK Harman Group and PSB are using DBT for loudspeaker design.

In short: DBT is a scientific valid procedure regardless of any of our personal opinions.

Some of us feel more comfortable trying to have science at our side... some others simply prefer to adhere to a preconceived scheme of beliefs.

And still I think currect DBT methodology applied to audio could be improved.
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post #153 of 224 Old 12-30-2010, 12:26 PM
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Originally Posted by JorgeLopez11 View Post

Hi CDLehner.

It is true not all DBT audio tests are conducted properly, but that do not invalidate all of them.

MatrixHiFi people has put a good effort in those tests but unfortunately not all of them are strictly reliable, as Jose Almagro can testify.

But please do not come to wrong conclusione because (perhaps) you misunderstand these concepts: the test setup and the test conditions.

Some experts such as Sean Olive (AES member, BTW) among others have published peer reviewed scientific papers regarding this subject. I repeat, peer reviewed. And many conclusions have came up from those tests.

Moreover, AFAIK Harman Group and PSB are using DBT for loudspeaker design.

In short: DBT is a scientific valid procedure regardless of any of our personal opinions.

Some of us feel more comfortable trying to have science at our side... some others simply prefer to adhere to a preconceived scheme of beliefs.

And still I think currect DBT methodology applied to audio could be improved.

Jorge, that's fair enough. I never meant to imply all DBTs...or even all audio DBTs...or even all Matrix audio DBTs...were invalid or improperly conducted. I try not to make such generalizations.

As for my opinions about the fallacies of DBTs...audio and otherwise; hey...for the last time...I'm not a scientist. But I know how to Google; and some of the opinions I was relaying were not from Joe Johnson. They were from MDs and PhDs...and some of them point out the trap-doors of DBTs.

I'm from the school of common-sense, and all I can say is the second I even see a sign that says "audio testing, right this way"...my perception has got to change, from that of an audiophile sitting in his own room listening. You and every scientist and doctor from here to the Moon, can try and tell me otherwise...but I don't think they would...but I'm not buying.

Why does everyone keep saying "you should learn what a DBT really is"? Is it that great a mystery? Am I that far off? I'm in IT...are you not allowed to have an opinion about computers, until I put you through MCSE certification?

I refused to get sucked-in again. This is a DUMB argument...that, now that I've started to Google, for info from both sides of the fence...I realize is about as old as "hi-fi" itself. Like I said, we might as well be a couple of morons arguing about the chicken and the egg.

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post #154 of 224 Old 12-30-2010, 02:22 PM
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No test implementation is perfect; you can always critique it and point out ways it might be improved, or at least done differently. But that doesn't make its results invalid. The only way to invalidate those results is to conduct another test, with the alleged flaw(s) corrected, and see if you get a different result.

Sadly, the scientific illiterati who populate the audiophile fringe never do this. They'd rather remain illiterate.

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post #155 of 224 Old 12-30-2010, 03:02 PM
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Originally Posted by CDLehner View Post

A test in Spain means Spanish guys, sitting in some room, listening to some gear I've never heard of...trying to distinguish between tracks of their favorite pop star, Javier Domingo...and while that might hold weight in the universal, scientific community (after all, science is science)...I have NO frame of reference personally, so it means nothing to me.

I don't understand, Have you been to every place of your country and listened every stereo setup or is it a problem with foreigners?

We listen the same in Spain, sometimes we go to the king's palace (he's the owner of the only stereo) and make DBT and sometimes we listen Javier Domingo live while he's collecting bananas
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post #156 of 224 Old 12-30-2010, 03:22 PM
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Originally Posted by CDLehner View Post

Why does everyone keep saying "you should learn what a DBT really is"?Is it that great a mystery? Am I that far off?

Maybe because you stated quite clearly that you don't understand them, or the scientific method, just yesterday.

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Just because I choose not to respond, doesn't mean I don't have answers. But admittedly, they're not absolute answers...it would just be my opinion in response; and would therefore lead to more back and forth.

I'm really not interested; I intend for this to be my last post here. In fact, it's not even worth lurking anymore. For the record, I apologize for the name-calling (even though I was provoked )...and if, in the heat of battle, ever implied that I thought any of you "scientist" types were "wrong"; I don't.

Your arguments are entirely plausible, but I simply allow for more than one conclusion; I allow for subjectivity...and I simply choose to live my life that way.

Again, all I ever hear in response is "you're wrong...in 1996, Dr. Such and Who proved otherwise". Proved what exactly? Look, since this is a parting-shot, I'll leave you with one final observation. I've given this some thought; I don't just shrug my shoulders, and take what you contend as nonsense.

Here...in a nutshell (so to speak)...is what I don't get about DBTs. OK, so the control would feature everything the same, except a certain piece of gear, right. So...if we're testing 2 amps; the speakers are the same, the source is the same, the cables are the same, the power is the same, the room (and treatments) are the same?

Now...you take a CD-R, burned with 10 test tracks. Maybe a little Jazz, a little female vocal; some Orchestra...a movie soundtrack, some Rock, whatever. OK...now, you blindfold me, switch the amps, and I'm supposed to reliably be able to tell the $300 amp from the $5,000 amp, right? Is that 6 out of 10? I have to pick the expensive amp, or be able to correctly identify the difference?

OK, so if I'm right so far...and by all means, if I'm not...I apologize; I really don't understand the scientific process that well. I took as few Science credits as I needed to complete my degree...lol. So...do I know any of these test tracks? Is it music I am intimately familiar with, so as to be able to discern what I'm even listening for in the first place...let alone tell the difference? I suspect...in most cases...not (I know you guys did mention one study where the subject used his own music, which I think is terribly important...but are the "majority" of tests like this?).

OK, another point of contention: let's say that for 9 out of the 10 tracks, sometimes I picked the $300 amp as sounding "better", and sometimes I picked the $5,000 amp. So my preference was inconclusive. But let's say, that on one track...the Natalie Merchant female vocal test...that 8 out of 10 times I was able to identify the $5,000 amp as reproducing that track in a way I was able to identify as more "pleasing"? That wouldn't make the overall test conclusive...but, would I be willing to pay $4700 more for an amp that made Natalie Merchant (and maybe other, sweet-sounding females) consistently sound better? Maybe. Maybe I wouldn't...but if a guy with money to burn wanted to, I wouldn't blame him one bit.

See...one of the reasons I've...admittedly...never looked at any of these DBT studies, is I don't get them. I think it's "slanted", for lack of a better word. Again...I'd need to know what they're listening to...how well they know the tracks; which tracks did they "miss", which tracks did they not. Got anything with some "real-world" music? This hardcore, Led Zeppelin fan...couldn't tell the difference between this amp and that amp, when listening to Stairway To Heaven 50 times? Again, I suspect not. Some of the studies I've seen don't come from this country (again, I understand science is science...but what are they listening to? AFC monitors, or a brand that isn't really popular here? So I have no frame of reference? Alan Akabackarack...who's a great Pop star there, but I don't know how discernible his music is? In other words, I wouldn't look for Britney Spears' music to challenge an audio system). Are these studies conducted in some hotel room, or a convention center? At some university listening room I'm uncomfortable in? Let me ask you this; if I know I'm being "tested", doesn't that alone put my brain in a different place than when I'm "relaxed", and listening in the comfort of my own home?

See; I just never saw the point. I just don't see how it's an apples to apples comparison. I mean, it all...and all of you, unfortunately...just come off like you're spouting lab-speak and citations. Now...that's just my opinion; you're entitled to yours, and you're free to shout me down now. Who knows...I might even peek in, so it won't go on blind eyes. But I won't respond; so I'm telling you now...don't fool yourself into thinking you've "run me off". I go of my own volition.

CD

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I'm in IT...are you not allowed to have an opinion about computers, until I put you through MCSE certification?

I'm in IT too. Where I work we generally deal in facts to come up with solutions, not opinions.
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post #157 of 224 Old 12-30-2010, 03:52 PM
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Originally Posted by jose almagro View Post

I don't understand, Have you been to every place of your country and listened every stereo setup or is it a problem with foreigners?

We listen the same in Spain, sometimes we go to the king's palace (he's the owner of the only stereo) and make DBT and sometimes we listen Javier Domingo live while he's collecting bananas

NO; I'll respond to this...because while I'll tolerate being called a lot of things, I want to make it clear I'm not a Xenophobe.

All I meant is I looked at one such study, from a posted link; and...for example...the speakers were some brand I had never heard of. Again...I stopped reading there, because I had no frame of reference. I don't know those speakers, so whether they're the best bang-for-the-buck $500 monitors, or $10,000 jobs...I wouldn't know their sound.

And honest to god...I totally made up "Javier Domingo", so please don't tell me he's a real performer. Although I think your hilarious parody makes it obvious you're needling me.

I'm just saying...right or wrong...and I'll always admit my foibles; if I read a study, where the primary tracks for testing were Britney's latest pop-synth, auto-tune masterpiece...I wouldn't lend that much credibility. So...in "foreign" studies, if I don't know the artists, I just can't make judgments.

AFAIC, Spain-type peoples make very nice with good stereo sound.

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post #158 of 224 Old 12-30-2010, 04:19 PM
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No test implementation is perfect; you can always critique it....

Pointing out that the test was conducted with background noise equivalent to a restaurant or a quiet factory isn't a "critique". That's a fundamental flaw in the test conditions.
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But that doesn't make its results invalid.....

Of course it does. Proper test design requires that the test conditions be such that observations aren't contaminated by outside factors. ITU-R BS.1116-1 stipulates a background noise maximum NR 15 and recommends NR 10 for similar tests. This test measured >NC 40, which isn't even close.
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The only way to invalidate those results is to conduct another test, with the alleged flaw(s) corrected, and see if you get a different result.

That's simply not true. No useful conclusions may be drawn from this test.
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post #159 of 224 Old 12-30-2010, 04:39 PM
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Originally Posted by CDLehner View Post

Unless I'm listening in my room, with my music, these results can't mean much to me. A test in Spain means Spanish guys, sitting in some room, listening to some gear I've never heard of...trying to distinguish between tracks of their favorite pop star, Javier Domingo...

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I'm not a scientist. But I know how to Google

As the joke goes, you just can't make this stuff up.
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post #160 of 224 Old 12-30-2010, 05:24 PM
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Proper test design requires that the test conditions be such that observations aren't contaminated by outside factors. ITU-R BS.1116-1 stipulates a background noise maximum NR 15 and recommends NR 10 for similar tests. This test measured >NC 40, which isn't even close.

Which would make the test less sensitive than would be ideal. But that still doesn't invalidate the results. The only thing that invalidates the results would be a test done with lower background noise that gets a different result.

We're waiting.

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post #161 of 224 Old 12-30-2010, 05:45 PM
 
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That's simply not true. No useful conclusions may be drawn from this test.

That's your biased opinion. It wouldn't necessarily be a problematic test if the music itself was loud enough to drown out the background noise.
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post #162 of 224 Old 12-30-2010, 05:49 PM
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As the joke goes, you just can't make this stuff up.

OK, so...it's inconsequential that I might not relate to the results of a test that has NOTHING to do with the way I listen to music?

And as far as not being a scientist (expert) myself...but knowing how to Google; so, in place of being an authority myself, you're suggesting I am not allowed to follow the opinions of other experts? What's next; reading is bad?

Didn't you guys Google those stoopid studies you posted? I clearly said "this wasn't Joe Blow's opinion I Googled; they were MDs and PhDs, right along with some of you". But then again, snipping something out of context, and commenting on it is about as asinine as it gets.

I think you're right about the way the joke goes.

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post #163 of 224 Old 12-30-2010, 05:59 PM
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Which would make the test less sensitive than would be ideal. But that still doesn't invalidate the results. The only thing that invalidates the results would be a test done with lower background noise that gets a different result.

We're waiting.

It's not "less sensitive than would be ideal", it's much less sensitive than the minimum requirements necessary to permit useful observations, as defined by BS.1116-1. To put it differently, since minimum necessary test conditions weren't met, the observations are of no value and any conclusions ditto.

Wait all you wish, but no new test is required to invalidate this one.
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post #164 of 224 Old 12-30-2010, 06:51 PM
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It's not "less sensitive than would be ideal", it's much less sensitive than the minimum requirements necessary to permit useful observations, as defined by BS.1116-1. To put it differently, since minimum necessary test conditions weren't met, the observations are of no value and any conclusions ditto.

Not quite. Its less sensitive than the minimum that would be acceptable to the ITU (for testing audio codecs, I believe). But that does not make the test meaningless. It can still be said of it that no one in the test was able to detect a difference under those conditions. If you want to claim that anyone could detect a difference under better conditions, you need to create those conditions, run a test, and produce a better result.

Just as an aside, I wonder how many audio showrooms or home listening rooms would meet the ITU standard. At the very least, this standard would seem to invalidate the "my wife could hear it from the kitchen" claim.

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post #165 of 224 Old 12-30-2010, 08:33 PM
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Originally Posted by RUR View Post

It's not "less sensitive than would be ideal", it's much less sensitive than the minimum requirements necessary to permit useful observations, as defined by BS.1116-1. To put it differently, since minimum necessary test conditions weren't met, the observations are of no value and any conclusions ditto.
.

I guess this also applies to all the claims by the 'golden ears' for audible differences if they don't follow the BS 1116- protocols, right? So, none of theirs have any meaning what so ever, right? How many of their claims do you challenge? Any?
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post #166 of 224 Old 12-30-2010, 08:39 PM
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Not quite. Its less sensitive than the minimum that would be acceptable to the ITU (for testing audio codecs, I believe).

"Small impairments in audio systems" technically. This test protocol is often cited as a basis for useful audio gear DBT's, even at hydrogenaudio. I doubt you'll find a more appropriate test method approved by ITU/AES, but if you can, we can discuss it. It's a cinch none will permit anything close to NC40 background levels, though.
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If you want to claim that anyone could detect a difference under better conditions, you need to create those conditions, run a test, and produce a better result.

I've made no such claim. Only that the test, as conducted, does not prove "no difference" for the two units under test, based upon a known and widely-accepted test standard.
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At the very least, this standard would seem to invalidate the "my wife could hear it from the kitchen" claim.

Oh, I think we both know the root cause for those claims.
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No useful conclusions may be drawn from this test.
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Only that the test, as conducted, does not prove "no difference" for the two units under test, based upon a known and widely-accepted test standard.
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post #168 of 224 Old 12-31-2010, 02:25 AM
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That's your biased opinion. It wouldn't necessarily be a problematic test if the music itself was loud enough to drown out the background noise.
You can't re-escalate your hearing system. A NC-40 is about 50 dBA, here in Spain, if you have more than 30 dBA at home, you can sue the noise maker. Do you honestly think that turning the volume louder you can make a DBT?
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post #169 of 224 Old 12-31-2010, 02:39 AM
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NO; I'll respond to this...because while I'll tolerate being called a lot of things, I want to make it clear I'm not a Xenophobe.

All I meant is I looked at one such study, from a posted link; and...for example...the speakers were some brand I had never heard of.
I wasn't calling you xenophobe. Nowadays everybody has a kind of UN in their system. You can see a pair of JBL and another of Dynaudio.

At home I have:
CD Player: Nederlands
Turntable: Swiss
Phono preamp: UK
DAC: USA
Preamplifier: USA
Amplifier: Spain
Loudspeakers: Australia
Our test records can be Chesky, Telarc or TBM just like yours.

And I just realized I have nothing from my beloved Scandinavia.

So I think it's easier to find the same components in USA, Japan or wherever so the problem is not where or who... is how.

PS: We have no Javier Domingo, only the tenor Plácido Domingo
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post #170 of 224 Old 12-31-2010, 06:11 AM
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Your point? Those two statements are entirely consistent with one another.
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post #171 of 224 Old 12-31-2010, 07:24 AM
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I've made no such claim. Only that the test, as conducted, does not prove "no difference" for the two units under test, based upon a known and widely-accepted test standard.

But even a perfect test protocol cannot prove that. It can only prove that a difference wasn't detected in that test.

And ask yourself this: What if the outcome had been positive (which some Matrix tests were). Would the test be invalid? Or could we confidently assert that a difference was heard? Obviously the latter.

So are we in a position where a test is valid if it gets one result but totally invalid if it gets another? And is that a position we want to be in?

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post #172 of 224 Old 12-31-2010, 07:29 AM
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Originally Posted by jose almagro View Post

I wasn't calling you xenophobe. Nowadays everybody has a kind of UN in their system. You can see a pair of JBL and another of Dynaudio.

At home I have:
CD Player: Nederlands
Turntable: Swiss
Phono preamp: UK
DAC: USA
Preamplifier: USA
Amplifier: Spain
Loudspeakers: Australia
Our test records can be Chesky, Telarc or TBM just like yours.

And I just realized I have nothing from my beloved Scandinavia.

So I think it's easier to find the same components in USA, Japan or wherever so the problem is not where or who... is how.

PS: We have no Javier Domingo, only the tenor Plácido Domingo

No JA; completely valid. Of course my system is not filled with only American-made components (that really would make me a Xenophobe...lol). My only point was some of the studies I've seen...conducted in other countries...tended to have at least one component I was unfamiliar with.

For example; one study was conducted using a pair of monitors I had never heard of. Now, I try to keep on top of things, but just because I hadn't heard of them doesn't mean anything, good or bad. In fact, my first thought might be "why are they using speakers no one's ever heard of...what are they trying to hide"...lol. Then my brain kicks in, and reminds me that not all parts of the World follow the same consumer path that we do.

I also don't claim I've heard all brands that are "well-known" or "popular" in the US. For example, if I came across a study that used Harbeth monitors; I've never had the pleasure...but at least I have the frame of reference...right or wrong...agree or disagree...that they are an accurate, well-regarded (if thought to be a bit timid) speaker. So...in all honesty...if I were reading a study, and they were using Harbeth's, with a flea-watt SET...and the subjects were fed a steady diet of Heavy Metal, and couldn't find differences among a DAC or CD source...in my admitted skepticism, I would be like "ah-ha...of course, with Harbeth's and a 3-watt SUN, you're not going to be able to rock the house and distinguish between sources using that kind of music".

I don't use this, I concede, far-fetched example (exaggeration to make a point guys) to further our objectivist v. subjectivist debate. Only to explain, how if I'm reading a study with gear I haven't heard, or at least heard of...I have no frame of reference for how I might interpret the results.

BTW, I am a Dyn-for-lifer; so I do value product from your beloved Scandinavia.

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post #173 of 224 Old 12-31-2010, 08:17 AM
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Originally Posted by mcnarus View Post

But even a perfect test protocol cannot prove that. It can only prove that a difference wasn't detected in that test.

That's correct, and it's of interest only because this particular test should no longer be cited as part of a body of evidence which suggests that all DACs sound the same. It's also of interest because it calls into question other, similar tests conducted by matrix. They may be problematic or they may not, but this test doesn't bode well.


Quote:


And ask yourself this: What if the outcome had been positive (which some Matrix tests were). Would the test be invalid? Or could we confidently assert that a difference was heard? Obviously the latter.

I suppose one could argue that the test was valid because the difference could be heard despite the handicap imposed by a high background noise level, but all tests should be done under appropriate conditions, so as to avoid such a debate.

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So are we in a position where a test is valid if it gets one result but totally invalid if it gets another? And is that a position we want to be in?

See above. No, it's not a position we want to be in.

Guys, this is sorta interesting and all that, but I have other fish to fry. I'm out unless someone posts new info about this or other matrix tests.
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post #174 of 224 Old 12-31-2010, 09:01 AM
 
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Originally Posted by jose almagro View Post

Do you honestly think that turning the volume louder you can make a DBT?

Turning up the volume (within reasonable range) can alleviate the background noise problem. Most of the participants didn't have problem with this (half way down) Benchmark and Behringer DAC comparison session. vvv

5) Has harmed you the atmospheric noise?
Yes: 14%
No: 86%
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post #175 of 224 Old 12-31-2010, 09:07 AM
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Originally Posted by RUR View Post

Guys, this is sorta interesting and all that, but I have other fish to fry. I'm out unless someone posts new info about this or other matrix tests.

RUR, on the nose! That's how I feel. I read, but to argue, and essentially say the same things, over and over...it's pointless. I might as well say "chicken", and those guys say "egg".

I have to admit; I am hardly ever the first one to walk away from a debate...lol. But the objectivists are relentless; and I don't necessarily mean that in a bad way.

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post #176 of 224 Old 12-31-2010, 09:10 AM
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Originally Posted by geekhd View Post

Turning up the volume (within reasonable range) can alleviate the background noise problem. Most of the participants didn't have problem with this (half way down) Benchmark and Behringer DAC comparison session. vvv

5) Has harmed you the atmospheric noise?
Yes: 14%
No: 86%

Hmm...I'm no you-know-what...lol; but you ask the subjects if the bad testing environment is an issue? Who's the scientist here?

CD

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post #177 of 224 Old 12-31-2010, 09:14 AM
 
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Your point? Those two statements are entirely consistent with one another.

Not entirely consistent. Kind of consistent at best but how do you draw a conclusion with so little detail available? It seems that you were looking for reasons to discredit DBT result that contradicts your preconceived notion and when you saw something that remotely resembles such reason, you went after it. As mcnarus pointed out, how do you know if that particular background noise level invalidates the test or not? Was the noise level in excess of 1db, 2, 10 or 20db? Has other DBT of DACs produce different result when the background noise criteria was met?

This DBT of Benchmark and Pioneer DV 515 produced consistent result with the aforementioned DBT. Well, it must be because of background noise, right?
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post #178 of 224 Old 12-31-2010, 11:07 AM
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**sigh**

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Originally Posted by geekhd View Post

Not entirely consistent. Kind of consistent at best...

No, they're entirely consistent. Re-read them in context, if necessary.
Quote:


....but how do you draw a conclusion with so little detail available?

The only detail I need to know is the measured background noise level. Already explained in earlier posts.
Quote:


......you saw something that remotely resembles such reason, you went after it.

It doesn't resemble a reason, it is a reason.
Quote:


As mcnarus pointed out, how do you know if that particular background noise level invalidates the test or not?

Already answered.
Quote:


Was the noise level in excess of 1db, 2, 10 or 20db?

Already answered by reference (NC40).
Quote:


Has other DBT of DACs produce different result when the background noise criteria was met?

This DBT of Benchmark and Pioneer DV 515 produced consistent result with the aforementioned DBT. Well, it must be because of background noise, right?

Not germane to the discussion at hand i.e. the (in)validity of this test due to improper test conditions. If you don't yet understand why that's true, I don't know what more to say. If you wish to present an alternate test method similarly accredited/authored by ITU or other recognized body, and which permits tests conducted @ NC 40 background levels, please do so.

BTW, the recommended NC measurement for a recording studio or concert hall is NC 15-20. There's a reason for that recommendation.
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post #179 of 224 Old 12-31-2010, 12:12 PM
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All a DAC does is reproduce an analog signal from digital samples. It doesn't make anything sound 'musical'.

The musicians are the ones that made the source sound musical, has nothing at all to do with the equipment. "musical" has no definition in signal processing.

xianthax,

Although one may think it to be so, there is not one true objectively "correct"
analog signal produced by a DAC achieved in practice. Yes - I understand that
one would hopefully get back the EXACT same analog waveform that was
processed by the ADC. However, one doesn't get that in practice.

Digital signal processing relies on digital filters, and we have no "perfect"
instantiation of a digital filter. See, for example; the excellent article by
Keith Howard entitled "Ringing False":

http://stereophile.com/reference/106ringing/

Even when you use a "linear phase" filter - supposedly "ideal" - you can get
acausal ringing when the filter reconstructs the analog waveform.

Digital processing doesn't give you the "exact" analog waveform you started
out with - it gives you an approximation. How good that approximation is
determines the "sound" of the DAC.

One would think that there is an objectively "correct" analog output from a
DAC. As stated above, the original analog signal is the "correct" analog
output. However, real world digital algorithms and electronics don't give you
that objectively "correct" result, but only an approximation to same.

Therein lies the "wiggle room" for different DACS to sound differently. One is
not the correct DAC because NONE of them are exactly "correct" in the
sense stated above.

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Physicist
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post #180 of 224 Old 12-31-2010, 01:39 PM
 
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No, they're entirely consistent. Re-read them in context, if necessary.

They are not. Former cites "No useful conclusions may be drawn from this test", meaning completely none, latter cites one criteria which is your guess because you have not compared it to or found the contradicting test result when the background noise criteria was met. Hypothetically, lets say you did and it turns out one way (or the other), then the DBT under higher background noise would provide a useful conclusion about how it can affect the listener's ability but then again you have not provided such comparison so it's unknown to you. But you still went ahead and concluded though.

Quote:


Not germane to the discussion at hand i.e. the (in)validity of this test due to improper test conditions. If you don't yet understand why that's true, I don't know what more to say.

"improper test conditions" didn't seem to have influenced most listeners as they answered so when asked. Some criteria may not be as critical as others, i.e. background noise level vs. volume level matching of DACs.

Quote:


If you wish to present an alternate test method similarly accredited/authored by ITU or other recognized body, and which permits tests conducted @ NC 40 background levels, please do so.

How much of background noise do you think influences the test mentioned on post #142?

Quote:


BTW, the recommended NC measurement for a recording studio or concert hall is NC 15-20. There's a reason for that recommendation.

I haven't seen you question this criteria when subjectivists claim their positive experience including your own. By the way, typical residential noise floor range between 35 to 45 db (40 - 50 db per EPA). That would invalidate at least half of those results and more per EPA, no?
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