Do Audio CD copying "DEGRADES" the sound? A Blindfold Test

[anirban420]

Hello All,

There is a common saying that the sound of the Original Audio CD degrades/changes when it is copied, just like the degradation of sound during Audio Cassette copy. Here I am presenting a Blindfold Test through public polling regarding this issue to address the phenomenon. The test result might indicate whether the sound change/degrade during CD copy or not.

Here is how I prepared the test. I used the song "So Gaya hain" sung by Lata Mangeshkar from the movie Zubeidaa, music by A R Rahman. I have the original disk, bought a year back, the label of which is Sony Music having the serial number 500521 2. Let's assume the original disk as "Copy 0". I copied the CD using the "Disk Copy" method of Nero 8.1 Ultra. Let's assume this copy as "Copy 1". Next, I copied the "Copy 1" CD to create "Copy 2" CD by again using Disk Copy. Again I copied "Copy 2" to create "Copy 3" and so on. I created ten sequential "Copy" using this disk copy method. From each "Copy" disk, including the mother CD {"Copy 0" disk), I ripped the above-mentioned song using Exact Audio Copy v1.3 (EAC). Therefore, I got eleven rips of the same song from every "Copy".

I am presenting four rips of the song herewith attached as a ZIP file (HFV_CD_Copy_Test.zip, 201 MB). Due to the attachment size limitation of HFV, I have uploaded the zip file in Google Drive which can openly be accessed through the DOWNLOAD button at the end of this post. I have used rips from the following "Copy" -
1) mother CD
2) 6th copy
3) 9th copy
4) 10th copy
For the Blindfold testing, these songs are randomised. There are four audio files in the zipped archive named 01.wav, 02.wav, 03.wav and 04.wav.

To participate in the test, please download the zip file, read the included Readme.txt and compare the 4 included .wav files by listening to them in your best sound setup. You need to find the best sounding file among the four presented files. Please express your observation in the public poll mentioned at the beginning of the thread (please don't post your observation as a public post in this thread). The test will be valid for two weeks and I will publish the result on 1st June 2020. The result will denote that which file was taken from which "Copy".

Any discussion is welcome either in this thread or through personal communication.

DOWNLOAD

 

[haisaikat]

I was surprised by the results, must try for all. Good effort @anirban420 may be your PhD could also had been in a similar field. Ha ha

 

[subhashis_1980]

Well I have been a part of these tests twice before and believe me it's damn difficult to identify the worst version. Anyways I will try to make some honest predictions this time.

 

[subhashis_1980]

Hello All,

There is a common saying that the sound of the Original Audio CD degrades/changes when it is copied, just like the degradation of sound during Audio Cassette copy. Here I am presenting a Blindfold Test through public polling regarding this issue to address the phenomenon. The test result might indicate whether the sound change/degrade during CD copy or not.

Here is how I prepared the test. I used the song "So Gaya hain" sung by Lata Mangeshkar from the movie Zubeidaa, music by A R Rahman. I have the original disk, bought a year back, the label of which is Sony Music having the serial number 500521 2. Let's assume the original disk as "Copy 0". I copied the CD using the "Disk Copy" method of Nero 8.1 Ultra. Let's assume this copy as "Copy 1". Next, I copied the "Copy 1" CD to create "Copy 2" CD by again using Disk Copy. Again I copied "Copy 2" to create "Copy 3" and so on. I created ten sequential "Copy" using this disk copy method. From each "Copy" disk, including the mother CD {"Copy 0" disk), I ripped the above-mentioned song using Exact Audio Copy v1.3 (EAC). Therefore, I got eleven rips of the same song from every "Copy".

I am presenting four rips of the song herewith attached as a ZIP file (HFV_CD_Copy_Test.zip, 201 MB). Due to the attachment size limitation of HFV, I have uploaded the zip file in Google Drive which can openly be accessed through the DOWNLOAD button at the end of this post. I have used rips from the following "Copy" -
1) mother CD
2) 6th copy
3) 9th copy
4) 10th copy
For the Blindfold testing, these songs are randomised. There are four audio files in the zipped archive named 01.wav, 02.wav, 03.wav and 04.wav.

To participate in the test, please download the zip file, read the included Readme.txt and compare the 4 included .wav files by listening to them in your best sound setup. You need to find the best sounding file among the four presented files. Please express your observation in the public poll mentioned at the beginning of the thread (please don't post your observation as a public post in this thread). The test will be valid for two weeks and I will publish the result on 1st June 2020. The result will denote that which file was taken from which "Copy".

Any discussion is welcome either in this thread or through personal communication.

DOWNLOAD

Just to give a reference to where it started - https://www.hifivision.com/threads/kolkata-audio-meet-virtual-apr-2020.79125/#post-871043

I was surprised by the results, must try for all. Good effort @anirban420 may be your PhD could also had been in a similar field. Ha ha

He did his phd(passed high school with difficulty) in bio-chemistry. Let's conduct his viva in one of the meets. @anirban420 please forward your thesis(soft copy) to me and @haisaikat for our reference and questions

 

[anirban420]

He did his phd(passed high school with difficulty) in bio-chemistry. Let's conduct his viva in one of the meets. @anirban420 please forward your thesis(soft copy) to me and @haisaikat for our reference and questions

Just to rectify you @subhashis_1980, I did my PhD in Plant Biotechnology, not in Biochemistry. BDW, nice and innovative full form of PhD you have used .

Soft Copy of my thesis will soon be provided to both of you once it is published in the thesis archive of Calcutta University

 

[Hiten]

Thanks for the effort,
Since difference may be small. if possible hide the poll results. As seeing them might influence the polling.
Regards

 

[anirban420]

Thanks for the effort,
Since difference may be small. if possible hide the poll results. As seeing them might influence the polling.
Regards

You are right. But I can not see the edit button anymore. Is there any possibility to change the option of the poll?

 

[Hiten]

You are right. But I can not see the edit button anymore. Is there any possibility to change the option of the poll?

Sorry I dont know. May be they have option when starting a poll. Not sure.
regards

 

[bhaskarcan]

This is a very interesting poll. Actually I am yet to meet someone who claims that a copied CD sounds "discernibly" different than the original one. Here the operative word being "Discernibly". As of my experience, that perceived minute difference in sound maybe caused by "Placebo effect" of knowing that the CD in question is copied. This poll should end the debate in a scientific way.
As for the various commercial versions of a particular CD, there are many variables that may make one version to sound different from another one. For example, use of original music source to be transferred on the particular CD, type of mastering/remastering etc to name a few. That part is beyond the scope of this poll, IMHO.

Regards

 

[Naturelover]

You are right. But I can not see the edit button anymore. Is there any possibility to change the option of the poll?

I have changed the settings. Hope that is what you wanted

 

[anirban420]

I have changed the settings. Hope that is what you wanted

Thnks. When the result of poll can be seen? After ending I guess?

 

[Hiten]

I appeal everyone to take the test. More data more conclusive results.

 

[keith_correa]

The files are not bit identical.

 

[anirban420]

The files are not bit identical.

Yes I know, thts why I arranged this blindfold test. Technically speaking, every file is different. But the goal of this study is to know whether it impact our listening pleasure or not in our available system. Please cast your vote according to your listening experience. Audio listening is all about listening pleasure IMHO

 

[spirovious]

The files are not bit identical.

How did you check it? If I check their properties, all are -

File Size : 54.4MB (57 146 588 bytes)
Duration : 5:23.960 (14286636 samples)
Sample Rate : 44100 Hz
Bits Per Sample : 16
Bitrate : 1411 kbps
Codec : PCM
Encoding : lossless

 

[anirban420]

For technical curiosity, I encourage to check the files in any audio editor, hexeditor or any other kind of file checking method. The visible difference is there. But my question is can we "HEAR" what we are "SEEING"?

But I am curious to know how @keith_correa assessed the files....

 

[keith_correa]

If you're inclined to, can you please rip the same track from the different CD's again and upload the log file from EAC? I'm curious to know if the ripping is identically done.

 

[Sean de Silva]

DOWNLOAD

I've tried twice to access your google Drive files via that link and this is what happens..



And then this.


The reason I'm curious to hear your samples and draw an inference is because I'm currently ripping my audio CDs via dbp to wav uncompressed !

 

[anirban420]

@keith_correa I have EAC log for every rip of this song. There are errors in some rips, some are not 100% perfect as the source, this phenomenon is well depicted in the visual observation through different tools. But the trend is not proportionate with the sequential copy. As for example, suppose "Copy 4" have read error, but "Copy 8" don't have any error and 100% identical rip. I have chosen the presentation files randomly on purpose, regardless of error, because I want to know whether these visual imperfections affect our audio reception or not. To keep the experiment unbiased, I can not share the logs now but will share those with you, if interested, after the poll ends. Presently I can only say that some presented file(s) has/have error according to EAC log.

@SEANDSILVA Please use a computer to download and extract the provided zip file. Zip file having 201 MB size might be problematic for a mobile device.

 

[Sean de Silva]

@SEANDSILVA Please use a computer to download and extract the provided zip file. Zip file having 201 MB size might be problematic for a mobile device.

Ok! Thanks for the quick reply.