How To tell between a 'real' FLAC and a 'fake' FLAC?
May 31, 2015 at 5:24 PM Post #31 of 50
  Hi, sorry for digging out an old thread, but I have a question regarding these spectral diagrams. I'm not sure how to interpret these two MP3 files and would love some help.

So the first one is a a 256 kbps MP3 file ripped a long time ago using iTunes.
The second one is a 320 kbps MP3 file, converted from a FLAC version to MP3 via XLD.
 

 
 
 
Is this normal? According to http://www.whatinterviewprep.com/prepare-for-the-interview/spectral-analysis/,
 
It looks to me my "256 kbps" file fits the 320 kbps description more. Is there something wrong with my XLD? Or is everything fine and I'm just confused? Thanks so much. :)

 
 
Yes, what you have in general looks normal.
 
Jul 4, 2015 at 4:55 AM Post #32 of 50
The site went down I am afraid but I am still able to download via the mirror.
http://wayback.archive.org/web/20141113151216/http://spectro.enpts.com/download.php
In case the above went down too, here is a backup: https://drive.google.com/folderview?id=0B151yw6KLtfGfm9XRUVtN0tpbk9JS2ZiN21aQ0R1bDFVaS1pY293T01xOFhZQVJjNjYwcTQ&usp=sharing
 
If both failed, google Spectro 1.0.93.
 
The homepage
http://wayback.archive.org/web/http://spectro.enpts.com/download.php
 
Apr 26, 2016 at 12:45 AM Post #33 of 50
Hey man, 
 
The last years i am using a free tool, the best in my opinion. Its for windows,mac and Linux and its called SPEK. http://spek.cc/
 
You just drop the file there. I have tested it on 24/96khz and it worked fine. Give it a try and you'll love it.
 
May 1, 2016 at 11:07 AM Post #34 of 50
Spectro is great, but can't handle single-track lossless releases (image + .cue). Makes me wish to make a similar program, but with no such limitations and with batch mode support (e. g. "scan everything within the specified set of folders").
 
Sep 12, 2016 at 5:57 PM Post #37 of 50
I tried Spectro with some of the CD's I ripped using Media Go, and it shows a cut-off frequency of 20.5 KHz.
What is more confusing is, one album I bought from Qobuz.com shows 16.5 KHz! (Although the graph shows spikes here and there all the way to 20 KHz. 

The upper limit of human hearing is 20 KHz. Could it be that the flac encoder is cutting the frequency off there somehow?? So confusing. 
 
Sep 12, 2016 at 6:15 PM Post #38 of 50
  I tried Spectro with some of the CD's I ripped using Media Go, and it shows a cut-off frequency of 20.5 KHz.
What is more confusing is, one album I bought from Qobuz.com shows 16.5 KHz! (Although the graph shows spikes here and there all the way to 20 KHz. 

The upper limit of human hearing is 20 KHz. Could it be that the flac encoder is cutting the frequency off there somehow?? So confusing. 

 
Nop, FLAC does not cut anything. It is lossless, so nothing is lost. It compress the audio like a ZIP file, and the player descompress without loosing quality.
 
Did you tried to check your files with AccurateRip? CueTools or Perfecttunes can do this. Only dBpowerAMP or EAC can upload rip results to the AccurateRip database. So, if you FLAC or whatever lossless format you are using gives at least V2 of confidence, it is a perfect rip. So, with this method you can check if the files are real AND if they was properly ripped.
 
Sorry for my bad english.
 
Sep 12, 2016 at 6:28 PM Post #39 of 50
   
Nop, FLAC does not cut anything. It is lossless, so nothing is lost. It compress the audio like a ZIP file, and the player descompress without loosing quality.
 
Did you tried to check your files with AccurateRip? CueTools or Perfecttunes can do this. Only dBpowerAMP or EAC can upload rip results to the AccurateRip database. So, if you FLAC or whatever lossless format you are using gives at least V2 of confidence, it is a perfect rip. So, with this method you can check if the files are real AND if they was properly ripped.
 
Sorry for my bad english.

Good idea. Will try it. Thanks :)
 
Nov 30, 2016 at 4:30 AM Post #41 of 50
What could I use if I have a huge FLAC file? I downloaded an album, but it turns out the whole album came in one FLAC file. It's 36 minutes long. Spectro says it's too large to process, but i'd really like to make sure it's solid.
 
Thanks!
 
Nov 30, 2016 at 7:59 AM Post #42 of 50
  What could I use if I have a huge FLAC file? I downloaded an album, but it turns out the whole album came in one FLAC file. It's 36 minutes long. Spectro says it's too large to process, but i'd really like to make sure it's solid.
 
Thanks!


CUETools.
 
Here is a good tutorial: https://losslessma.net/how-to-split-and-convert-single-file-flac-album-into-tracks/
 
Nov 30, 2016 at 8:40 AM Post #43 of 50
The spectral analysis is the most reliable way to find out about lossy compression but it's not perfect.

Masters and audio processing can produce artifacts that can ultimately end up looking like a compressing algorithm was used at some point. Ultimately the auCDtect algorithm tries to do the same thing you are doing by naked eye. Algorithms work better or worse than humans depending on the problem.
 
Quote:
  Hi, sorry for digging out an old thread, but I have a question regarding these spectral diagrams. I'm not sure how to interpret these two MP3 files and would love some help.

So the first one is a a 256 kbps MP3 file ripped a long time ago using iTunes.
The second one is a 320 kbps MP3 file, converted from a FLAC version to MP3 via XLD.
 

 
 
 
Is this normal? According to http://www.whatinterviewprep.com/prepare-for-the-interview/spectral-analysis/,
 
It looks to me my "256 kbps" file fits the 320 kbps description more. Is there something wrong with my XLD? Or is everything fine and I'm just confused? Thanks so much. :)

 
That is largely depending on the encoding used. It looks like you're using CBR since it cut offs and sometimes the peaks go higher (when the data rate allows it). Try to change the scale of the frequency on your spectral analyzer to get further information on the upper frequency range.
 
 
Dec 3, 2016 at 6:45 AM Post #45 of 50
  What could I use if I have a huge FLAC file? I downloaded an album, but it turns out the whole album came in one FLAC file. It's 36 minutes long. Spectro says it's too large to process, but i'd really like to make sure it's solid.
 
Thanks!


Spek is the best tool I know.
 

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