What makes CD/SACD players "burn in"?
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briano

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Has anyone ever ABX'd a new component? I'd like to see a post from someone who had both a new component and a component broken in for 72 hours side by side and could tell the difference in a blind test....

Not to co-opt the thread, but how about this:

Someone with a new component (Let's say CD player...) and a nice sound card can put in their favorite test CD (as in something we can listen for differences with).

Record from the CD to the high quality line in. Maybe 1 minute of good test music.

Burn in the CD player.

Repeat.

Post the WAV files, and we can use the PCABX tester (found at www.pcabx.com) to do blind testing on our own. People can then post their scores here and we will find out if there is a difference.

Any takers?
 
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post-186710
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Nadim

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Quote:

From fredpb:
I got the shock of my life. Stuff DOES sound different. As far a those who say "it ain't in the book", that's their opinion. It is quite possible they don't have the hearing ability or desire to hear a difference.


Hehe, I feel like I've read a couple books worth of discussion on these topics, and found an abundance of people on both sides of the argument. There are people who'll swear on their mother's grave that the difference is as clear as night and day, black and white. Meanwhile, others would happily take the same oath that nobody could tell the difference under controlled, blind-test conditions. Maddeningly, it doesn't even look like things are converging upon a more universal view anytime soon.

While everyone is entitled to their own opinion, as you do admit, I feel that statements like "It is quite possible they don't have the hearing ability or desire to hear a difference" and "If you can't tell the difference, it's cheaper that way, and you can always buy your equipment at Radio Shack" are a little unfair. They remind me of the not-so-subtle routines used by some of my coarser friends in college...you know...."That's okay, you don't have to do another shot of tequila...only real men will be drinking this round."


I'm absolutely sure you feel there is a difference. And, in the absence of any proof more substantial than your feeling, I'm more than happy to allow the possibility that there really was a significant change in the sound, if you'll allow the possiblity that your sense of change was caused (in part, perhaps) by other factors, whether they be psychoacoustic, familiarity, or just time. When I stated earlier that "I never heard anything in class...", it certainly wasn't meant to imply that I am incapable of believing something that wasn't in one of my textbooks (otherwise I'd be ignorant indeed...). Rather, I said it because it's my opinion that, given the less-than-iron-clad evidence from either the "yes it does" or the "no it doesn't" camps, one could do worse than apply what rational knowledge that one has to arrive at a starting point for further contemplation.

You should understand that for those of us (like myself, or presumably Leo, who asked the original question in this thread) who are relatively new to this whole arena, its kind of frustrating to be looking for an answer and be presented with such a wealth of vehemently held, yet diametrically opposed answers.

Personally, I try hard to keep an open mind on the whole subject, and in fact I'm all excited about having the day off tomorrow, so I can head over to the one store I've found in my local area so far that actually carries some decent headphone gear, and check out my ER-4Ps through some of their amps, sources and cables, so I can try to isolate what effects the various higher-end components do for the sound.

Quote:

from briano:
Has anyone ever ABX'd a new component? I'd like to see a post from someone who had both a new component and a component broken in for 72 hours side by side and could tell the difference in a blind test...


Well, briano, if you were attempting to rise to the challenge and find a topic more controversial than burn-ins, you did a great job!


I don't know for sure, although I've been trying to find good ABX materials on the web, and haven't run across anything like that just yet. You might want to ask on rec.audio.high-end or rec.audio.opinion, I've observed that some of the original ABX proponents are active on those groups (ironically, still duking it out with the same original anti-ABXers...they've been going at it for 20 years now!)

As for your suggestion as to how to use PCABX to do a test....well....as much as I'd love to see some ABX testing done along-side the more subjective reviewing that goes on (not in place of it, of course), I'm obliged to point out to you that I'm quite confident that your idea wouldn't work in this case. Unfortunately, hearing the effects of the burn-in period on the DAC and buffering circuitry in a CD player can't be effectively done if you're taking that output, re-digitizing it into a WAV file (using the computer's ADC circuits), then playing it back later through different DAC circuits and amplification... As far as I know, the PCABX tester was designed for, and is pretty much limited to, testing software like mp3/mp3pro/wma/ogg encoding and or decoding algorithms.

-Nadim
 
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post-186713
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Leo V

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Quote:

So, after all this, just out of curiousity....did you hear a difference after your pink noise burn-in period? And if so, about how great a difference would you say it made?


After ~40 hours of pink noise burn-in (preceded by another ~30 hours of music burn-in), I have listened critically to a few pieces I previously used as a basic of comparison with my old setup. I also made sure to keep the headphone volume level at my original setting. Much of the perceived improvement may have come from simply becoming more thoroughly familiar with the music and source, but some may have originated from break-in.

I definitely find the same pieces more enjoyable now. The sound does appear more detailed at both low and high volume levels, the fidelity seems to be more effortless--I don't seem to get tired at all listening in closed cans. The smoothness is definitely quite enjoyable now. I also seem to notice some artifacts of recording that I haven't noticed before (could be due to insufficient listening, but you never know!) I believe that I hear slight hiss associated with individual tracks for different instruments: for example, even in some Telarc recordings, some instruments play their parts sporadically, and the engineers seem to cut off the track when not in use. But when they play a part, the reproduction is sufficiently transparent that slight added hiss becomes detectable. At least that's my speculation


So far, I am less skeptical that there is *something* to this after all. Whether it's my ears or the equipment, the same music is more enjoyable now than 4 days ago.

PS: I have asked an engineer (in the microprocessor field) about whether you can "burn-in" a solid-state D/A converter. His answer was no, in fact he said the following:

Quote:

As far as burn-in of DAC's. I can't think of anything that could cause this effect. Every modern logic manufacturer burns in their semiconductor products after packaging to reduce "infant mortality". I have heard of companies that don't bother to test after burn-in aside from Iddq - a test that looks for short-circuits. But I haven't heard anyone who skips burn-in altogether. It would be an odd tactic to take based on the high amount of infant mortality out there (parts that will fail within the first 6 months of operation are "infant mortality") on even the best process.


In other words, companies already burn-in chips, to verify their non-defectiveness. This makes me wonder: why don't hi-fi audio shops do their own "burning in" before selling their gear? Don't they want the best initial impressions from their customers? Maybe there is a degree of validity to both sides of the break-in argument...
 
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briano

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Quote:

Originally posted by Nadim
I'm obliged to point out to you that I'm quite confident that your idea wouldn't work in this case. Unfortunately, hearing the effects of the burn-in period on the DAC and buffering circuitry in a CD player can't be effectively done if you're taking that output, re-digitizing it into a WAV file (using the computer's ADC circuits), then playing it back later through different DAC circuits and amplification... As far as I know, the PCABX tester was designed for, and is pretty much limited to, testing software like mp3/mp3pro/wma/ogg encoding and or decoding algorithms.

-Nadim [/B]




What about oversampling at 96KHz (or higher)? Is there a true adiophile here who can hear above 48KHz? Certainly, if there is a difference in the analog output of the CD player, I can capture that difference with an ADC of appropriate frequency? What frequency do audiophiles need? I think I have a Metrum tape drive at work that records analog up to 1 MHz. Is this high enough? I would think that if we are playing this back on headphones known to roll off at 32 KHz, we would be happy with a recording at 96KHz.

I totally agree that we would not hear the same sound that the CD owner heard originally since it has been through two more A-D D-A conversion on different hardware, but maybe we could hear the difference.

The presumption seems to be that we would NOT hear a difference and that it is already time to start explaining away the experiment so that we can continue to be positive that there is a difference.

Maybe we would hear a difference, then we could put the whole issue to rest.
 
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fredpb

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I have noticed that the "ABX box " has been mentioned in this thread. This is becoming "DBT" like thread. Moderators keep in touch with this thread.

I am very very familiar with the ABX box and it's creators and proponents. They have no interested in quality audio, but profess to debunk it. The insertion of the ABX device in itself nullifies many good audio component performance features.

I personally have chosen not to participate in the "rabid ABX users" forums because they have no open mind. And I can understand that, as I was like them for over 45 years.

I have received many shocks against my beliefs at audio shops where the people actually let me compare my equipment and CABLES to theirs, at different price ranges. To my dismay, I discovered things do sound different, and the differences range from subtle to just plain obvious.

I have no problem with people who say things are all the same.
They have a mindset, or hearing differences (some people are colorblind), or don't have the experience. They are entitled to have an opinion of their own of course.

I also get a bit rabid at times. I still contest the fact that an AC power cord can make a difference! No no no! BUT, I have ordered a cable of sufficient "difference in construction" to try out.
We shall see about that. I will keep and open mind and ear.

And those new at the audio game, or engineer, are usually under the impression they have all the knowledge there is because they are just out of school. They will learn. Especially when they get older and see the youngsters fresh out of school standing proud with their new knowledge.

There are those individuals who will realize there is more out there than was taught in school, and will start their own search.
This is how innovation is done. I sure am glad some of the engineers of the 60's did not stand pat on their education. Otherwise, we would not have the toys of today!

And my final stance on the ABX (DBT in disguise).... crapola.
 
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post-187055
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Leo V

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With all the strong feelings around conducting tests via hardware, why not just use an old-fashioned human, an impartial assistant? (Perhaps someone who doesn't have a stake in the results!) The subject in the test could wear a blindfold while the assistant could randomly switch (or not switch) between input sources. Or the subject could sit facing the other direction, or behind a cardboard shield.

So far, I see plenty of criticism of testing methodology, and zero enthusiasm to actually engage in any form of test. If the difference is "obvious", why not do it and give all of us a sanity check? I am mainly referring to the effects of "burn in" on CD players, but also any other differences subject to endless debate.
 
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dariusf

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Quote:

Originally posted by briano
What about oversampling at 96KHz (or higher)? Is there a true adiophile here who can hear above 48KHz?


You are confused here, the KHz you are referring to is the sampling rate that the recording was made at not the frequency of the sound. Oversampling just tries to fill in the missing sound or blur whats there to make it appear that there is more information, with in most if not all cases very good results.
 
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briano

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Quote:

Originally posted by dariusf
You are confused here, the KHz you are referring to is the sampling rate that the recording was made at not the frequency of the sound. Oversampling just tries to fill in the missing sound or blur whats there to make it appear that there is more information, with in most if not all cases very good results.


Actually, one of the frequencies I was referring to was the frequency of sampling (96 KHz) the other (48 KHz) is the theoretical maximum frequency which can be reproduced (or captured) using that sampling frequency (according to nyquist). The confusion you are referring to is related to my use of the term "oversampling". I believe that some digital audio OUTPUT[\B] devices do something that I would call "Interpolating". This would be making up samples that did not exist in the source material. I was talking about actually sampling at 96KHz at the input to the sound card. Soundcards that do this actually measure the voltage 96 thousand times each second, not interpolating.
 
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