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Topic: Identical source file / different conversion results (Read 4155 times) previous topic - next topic
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Identical source file / different conversion results

Hey guys, I have two MP3 specs here http://postimg.org/image/jz7omp23t/ - the one on the left was found online, the right is mine I converted from source (forget the different names, they are identical songs). The source file is a 22050hz,  2 channel WAV so obviously when I convert it to MP3 it retains its 10khz shelf. Yet the one I found online is the same spectral imprint  and sounds exactly the same and comes from the same 22050 source yet it stretches all the way up to a 20khz shelf and has an output sample of 44100hz. I am so confused by this, mainly because I cannot replicate it (every time I resample to 44100hz, the song is double the speed etc.) I'd appreciate it if someone could explain whatever is evading me here and how the converter was able to do this. Thanks!

Identical source file / different conversion results

Reply #1 –
That file is 44.1khz, not 22.05.

Identical source file / different conversion results

Reply #2 –
The one found online is not from a 22.05 kHz source.

As for the identical sound, almost all of the energy is in the lower frequency bands. The content above 10 kHz is extremely quiet; look at colors and compare to the scale on the right. You are only hearing the brightly colored parts, and the brighter it is and the more concentrated it is below ~6 kHz, the more it drowns out everything else. (The use of a logarithmic vertical scale would help here; the linear scale is squashing all the parts you're sensitive to into a very small space at the bottom of the graph. Spek is mainly used by people who are worried more about the uppermost frequency bands, though, so I assume that's why they use linear.)

Identical source file / different conversion results

Reply #3 –
Quote from: mjb2006 on
The one found online is not from a 22.05 kHz source.

As for the identical sound, almost all of the energy is in the lower frequency bands. The content above 10 kHz is extremely quiet; look at colors and compare to the scale on the right. You are only hearing the brightly colored parts, and the brighter it is and the more concentrated it is below ~6 kHz, the more it drowns out everything else. (The use of a logarithmic vertical scale would help here; the linear scale is squashing all the parts you're sensitive to into a very small space at the bottom of the graph. Spek is mainly used by people who are worried more about the uppermost frequency bands, though, so I assume that's why they use linear.)


Thanks guys, so I guess a better question would have been: "Is it possible for X to come from a 22.05KHz source", the answer to which would be 'no'. The audiological threshold of a 22.05KHz deems that it is incapable of reaching as the one displayed does. Thanks for clearing this up as well as adding extended dialogue about vertical scale representation. I'll look into it. I've just been frustrated lately trying to get old videogame music and seeing amazing sources and then some not so. The game in question here is Diablo, which has never had anything more than a lossy CD release yet somehow there exists a higher quality, possibly lossless version. I thought I would try replicate it from the only sources I know before spending hours trawling. Anyway thanks.

Identical source file / different conversion results

Reply #4 –
Perhaps this?

Quote
The music of Diablo was composed by Matt Uelmen. The soundtrack consisted of six tracks, it was released after 15 years, in 2011. It is called the "Diablo 15th Anniversary Music" CD.


https://en.wikipedia.org/wiki/Diablo_(video_game)#Music

Identical source file / different conversion results

Reply #5 –
Quote from: Blaice on
The game in question here is Diablo, which has never had anything more than a lossy CD release yet somehow there exists a higher quality, possibly lossless version.

This?
 

Identical source file / different conversion results

Reply #6 –
Thanks guys, yeah I already own this and had not made the connection until about a nanosecond after I last replied. It's definitely sourced from that. This community is amazing.