Meurglys0
2006-05-10, 02:01 PM
Hi.
Without noticing there was a whole section devoted to "lossy or not" I sent a private message to Five on Dimeadozen.org yesterday. So I thought I would post my question here too. Below is the message I sent Five :
I was checking some of the shows I have just recieved and I've got some suspicious spectral and freq graphs. And remembering you were experienced in detecting the source of audio files, I thought maybe you could take a look at them and let me know what you think about their possible sources...
If memory serves, I recall you don't support EAC for analysing audio but this is the only program I'm familiar with and till next month I won't have time to get used to another one and I thought maybe these graphs will also serve the purpose, so graphs from EAC are what I have.
In the frequency graphs of many shows, you'll notice, there's a drop off around 12-13 khz which is the main thing that made me suspicious. Because according to the audiohub page explaining how to detect mp3 audio (http://www.audiohub.org/get/fa/fa.htm) a drop-off caused by a mp3 source happens around 17-19 khz while on a mini-disc sourced audio this happens around 13-14 khz. The drop-offs however are not really so sudden drop-offs; they just tend to descend quickly after that point, that's all.
A line slicing the view on almost each spectral graph makes me think this is due to some remastering etc.. Because again according to audihub-mp3-detection-guide the spectral analysis shouldn't look so unnaturally tidy and linear. But I see this horizontal line in spectral analysis of many shows; do you know what casuses this? Is it really due to some remastering etc.?
Now I know that Leonard Cohen - 1993-05-27 - Frankfurt and Leonard Cohen - 1993-05-28 - Munich are DAT recordings. Also, Liveman (you know him, don't you?) told me his own copies of these shows produce the same graphs, and that he thinks the results are due to (maybe) the OKM mics used to tape the show, or some mastering process; so at least for those shows I am a bit relieved. Liveman also told me the same taper taped also the Leonard Cohen - 1988-06-01 - Royal Albert Hall, London show but with different equipment.
Anyway, I have included spectral+freq analysis for 2-3 tracks from each show that I am suspicious about. If you can take a look at these graphs I'd really appreciate it and be forever thankful.
You can download the graphs from :
http://rapidshare.de/files/20011763/Are_these_lossy.rar.html
I hope I'm not putting too much weight on you... I am, I guess. So please forgive me.
Thanks in advance.
Regards to all.
Without noticing there was a whole section devoted to "lossy or not" I sent a private message to Five on Dimeadozen.org yesterday. So I thought I would post my question here too. Below is the message I sent Five :
I was checking some of the shows I have just recieved and I've got some suspicious spectral and freq graphs. And remembering you were experienced in detecting the source of audio files, I thought maybe you could take a look at them and let me know what you think about their possible sources...
If memory serves, I recall you don't support EAC for analysing audio but this is the only program I'm familiar with and till next month I won't have time to get used to another one and I thought maybe these graphs will also serve the purpose, so graphs from EAC are what I have.
In the frequency graphs of many shows, you'll notice, there's a drop off around 12-13 khz which is the main thing that made me suspicious. Because according to the audiohub page explaining how to detect mp3 audio (http://www.audiohub.org/get/fa/fa.htm) a drop-off caused by a mp3 source happens around 17-19 khz while on a mini-disc sourced audio this happens around 13-14 khz. The drop-offs however are not really so sudden drop-offs; they just tend to descend quickly after that point, that's all.
A line slicing the view on almost each spectral graph makes me think this is due to some remastering etc.. Because again according to audihub-mp3-detection-guide the spectral analysis shouldn't look so unnaturally tidy and linear. But I see this horizontal line in spectral analysis of many shows; do you know what casuses this? Is it really due to some remastering etc.?
Now I know that Leonard Cohen - 1993-05-27 - Frankfurt and Leonard Cohen - 1993-05-28 - Munich are DAT recordings. Also, Liveman (you know him, don't you?) told me his own copies of these shows produce the same graphs, and that he thinks the results are due to (maybe) the OKM mics used to tape the show, or some mastering process; so at least for those shows I am a bit relieved. Liveman also told me the same taper taped also the Leonard Cohen - 1988-06-01 - Royal Albert Hall, London show but with different equipment.
Anyway, I have included spectral+freq analysis for 2-3 tracks from each show that I am suspicious about. If you can take a look at these graphs I'd really appreciate it and be forever thankful.
You can download the graphs from :
http://rapidshare.de/files/20011763/Are_these_lossy.rar.html
I hope I'm not putting too much weight on you... I am, I guess. So please forgive me.
Thanks in advance.
Regards to all.