Pardeep Bansal
Active Member
I also thought digital media is not affected by copying
Do Audio CD copying "DEGRADES" the sound? A Blindfold Test
- Thread starter anirban420
- Start date
If you are referring to:
The above is one of the observation, I was talking about insight into all observations.
Disagree?
anirban420
Well-Known Member
@alpha1 All the files are bit-imperfect. Therefore, every files are different to each other. It can be "seen" through various tools, but can not be "heard" notably by majority. You want to know the reason for it - was it your query?
BDW, similar situation can be found during other types of disk copy. I have discussed this phenomenon earlier in a post in this thread.
BDW, similar situation can be found during other types of disk copy. I have discussed this phenomenon earlier in a post in this thread.
Why have 25% of people preferred 01.wav and 03.wav over 02.wav and 04.wav?
D
Deleted member 15865
Guest
Poll or Test
The important question is ‘Was this a poll or was this a test’? Polls are usually conducted where people have opinion/choice (for example elections), and there’s no right or wrong opinion/choice - you are trying to assess what/whom the majority opines/chooses. This doesn’t seem to be that case. Here, either the samples are exactly identical (bit perfect or whatever the technical term for that might be) or they are not identical - and that’s a fact and not a matter of opinion. If they aren’t identical (as the OP confirms), and since these are subsequent copies, there’s logic in believing there was a progressive change (degradation). Degradation because it is highly improbable that sound magically improves with the progressive change, we are left with the conclusion that the sound worsened with each change introduced through subsequent copying.
Now, going back to the earlier refutation that this can’t be a poll (read above), it becomes a test of listening to spot this degradation. And a difficult test at that as the degradations are not substantial, but minuscule. It’s like a very tough IIT JEE mains question that only 10% get right. Now that 65% didn’t attempt it or 25% got it wrong doesn’t change the right answer. Because, it was a test and a not a poll to begin with.
The important question is ‘Was this a poll or was this a test’? Polls are usually conducted where people have opinion/choice (for example elections), and there’s no right or wrong opinion/choice - you are trying to assess what/whom the majority opines/chooses. This doesn’t seem to be that case. Here, either the samples are exactly identical (bit perfect or whatever the technical term for that might be) or they are not identical - and that’s a fact and not a matter of opinion. If they aren’t identical (as the OP confirms), and since these are subsequent copies, there’s logic in believing there was a progressive change (degradation). Degradation because it is highly improbable that sound magically improves with the progressive change, we are left with the conclusion that the sound worsened with each change introduced through subsequent copying.
Now, going back to the earlier refutation that this can’t be a poll (read above), it becomes a test of listening to spot this degradation. And a difficult test at that as the degradations are not substantial, but minuscule. It’s like a very tough IIT JEE mains question that only 10% get right. Now that 65% didn’t attempt it or 25% got it wrong doesn’t change the right answer. Because, it was a test and a not a poll to begin with.
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bhaskarcan
Well-Known Member
I agree that this was "test" in poll format. And as per my understanding, the test was to see if the sound degradation can aurally be differentiated by the majority of participants. Not to prove that there is "no" sound degradation.
Where I beg to disagree is
whoever voted, "attempted".
That means 100% "attempted".
Whoever couldn't identify the actual sequential rip from 0 to 10th copy or got one/two right, rest wrong, failed to get the correct answer. So here 65%+25%, 90+% got it wrong clearly. Even if someone identified 0 but failed in case of 6 (we see 2 votes for 0 and only 1 for the 6th) got it wrong wholely, as this was not a "test" of identifying the 0 only. The rips were spread over 0 to 10th to see if even the others(6th, 9th, 10th) can be identified or not. The 0 rip is here to keep the base reference.
So at the end we see, as per (minimum) 90% participants POV, the samples' degradation could not be differentiated "in a proper manner" by listening only.
D
Deleted member 15865
Guest
Once we say ‘as per’, it becomes ‘an opinion’. Again we get into the ‘poll’ territory. Semantics matter.
We can only say ‘90% participants could not differentiate on a proper manner by listening only’. I’d imagine many of those who didn’t get it right also believe the degradation can be differentiated, though they weren’t able to in this instance.
bhaskarcan
Well-Known Member
The title of the thread by itself clearly says "A Blindfold Test", so it's a "test", no matter we make out to be.
I didn't see anyone here claiming that the sound doesn't deteriorate further down the line. And that was the very target of this thread.
Even knowing well that degradation happened, more than 90% of listeners couldn't differentiate it convincingly.
So for the majority cases the generation loss while making CD copies do not influence the "listening pleasure".
Just downloaded and heard them on headphones. the file 1 and 4 are closer but 4 is more open, especially the mids. The 3 and 4 sound more congested especially the mids with poorer separation. Lows sound a bit more mushy on 3 and 4 with impact into the mids, but in 1 and 4, are more taut.
anirban420
Well-Known Member
Only the voters can explain it.
anirban420
Well-Known Member
It is a Test in a Poll format. Rest are nicely explained by our FM @bhaskarcan, many thanks to him. Similar tests on different topics are in the pipeline. Hopefully, I can execute the next test very soon.
I just want to add that the outcome of the test depicts that the "Change" (I would like to use the term "change" over "degradation" at this point of time) can not be aurally picked up correctly by the majority of the voter. Yes, there is "Change" happened during CD copy which can be identified by visual file checking tools. Still, the change is probably either so minute or corrected (possibly by error correction algorithm of the audio CD), it remains way higher than the threshold of listening pleasure. I have told earlier in a post of this thread that similar situation can be found during data CD copy (like Windows or MS-Office Setup disks). In that case, after so many generations of CD copy, the occurrence of a failed disk is rare, in turn, installation did not corrupt too. Therefore, it can be considered that, despite the minute difference, audio CDs can be copied without losing the substantial-quality that hampers our listening pleasure.
keith_correa
Well-Known Member
The analogy is incorrect. Data CD's (not the media per se) are different from audio CD's. The "extraction" process is different. Look up "seek jitter".
Some might find this interesting: https://john-millikin.com/🤔/why-i-ripped-the-same-cd-300-times
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It all depends on the hearing capability of the listener and the system he or she has. Your sample size is insignificant to arrive at any conclusions. If one can’t hear the differences, great. If one can, so be it. Ultimately you have to decide whether you find any differences or not.
subhashis_1980
Active Member
Hearing capability - yes, that's why we have this test to get a range of people voting. Anyone joining this forum - we can assume that he/she will have a certain minimum level of hearing and musical understanding else they wouldn't have been here, forget participating.
Coming back to system, yes I am sure we have varied system and so we are getting data from people having listened to budget, hi fi, super hi fi dac/amp combo. Some of us used headphones as well to understand better.
Now, this data is what we have. I am not saying that the sample is huge to formulate a law but it certainly shows certain trends and that trend indicates that copies from rips are not "degraded" sounding. Listening wise it's nearly the same.
@keith_correa I went through the site which you had provided but I didn't find any reference to hearing difference in ears. Please let me know if there's is, i might miss.
The bottom line is not whether the subsequent rips are bit perfect or accurate. We all know technically it degrades but can you detect it with your ears. Based on the data of this survey the answer is clearly No.
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blackscorpio
Active Member
IMO, this test is relevant only for the rips. The results would have been more relevant or it would have got a better result of what people can hear, if the test involved CD copy 10 vs RIP of Original CD.
I guess with the same set of people who voted, the results would be different if it were a test between original CD & Rip from Original. What this test essentially proves is it doesn't matter whether the files are ripped from Original or CD copy 10. A rip is a rip & lot of people can't make out the difference.
But there are many times it has been proved(may be wrong word but what I meant is if google there so many blind tests) that, not all but lot of people, can differentiate between a rip & CD.
I am noob so please take my comments with as much salt as you could afford.
I guess with the same set of people who voted, the results would be different if it were a test between original CD & Rip from Original. What this test essentially proves is it doesn't matter whether the files are ripped from Original or CD copy 10. A rip is a rip & lot of people can't make out the difference.
But there are many times it has been proved(may be wrong word but what I meant is if google there so many blind tests) that, not all but lot of people, can differentiate between a rip & CD.
I am noob so please take my comments with as much salt as you could afford.
subhashis_1980
Active Member
So to understand this test betterIMO, this test is relevant only for the rips. The results would have been more relevant or it would have got a better result of what people can hear, if the test involved CD copy 10 vs RIP of Original CD.
I guess with the same set of people who voted, the results would be different if it were a test between original CD & Rip from Original. What this test essentially proves is it doesn't matter whether the files are ripped from Original or CD copy 10. A rip is a rip & lot of people can't make out the difference.
But there are many times it has been proved(may be wrong word but what I meant is if google there so many blind tests) that, not all but lot of people, can differentiate between a rip & CD.
I am noob so please take my comments with as much salt as you could afford.
You would prefer a cd to be written(copy to copy) 10 times - then we have a rip and a original cd rip.
We can have 4 such files(rips from various copies) and the go for blind test. And your gut feel is people should be then be able to identify the actual cd rip.
Files - original cd rip, 10th copy to copy rip, 10th rip from eac and some other nth copy rip
I think it can be done @anirban420.. Your views please
blackscorpio
Active Member
Sorry If I miss understood. This files in this test are from Rip of Original CD & Rips from CD copy N.
what I meant is, if it is Original CD(played through a CD player) vs RIP of original CD (played through some transport connected to a DAC), most of the participants from the same group would have identified/noticed the differences. And IMO, CD would have won by lot of vote margin.
what I meant is, if it is Original CD(played through a CD player) vs RIP of original CD (played through some transport connected to a DAC), most of the participants from the same group would have identified/noticed the differences. And IMO, CD would have won by lot of vote margin.
subhashis_1980
Active Member
Unfortunately playing a cd through player and cd rip via dac doesn't have the same electronics.
So the rips were given for testing - orignal and other nth copy rips and in that testing, the data is indicating that human ears are not able to identify the differences.
anirban420
Well-Known Member
Are you talking about retesting the hypothesis with slightly changed procedure? It can be done. But the important factor is the "trend" of this test which you have already said. The trend clearly indicates that CD copy do not change the sound aurally. It can only be picked up visually.
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