Spectreum

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laurent....@gmail.com

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Nov 21, 2021, 8:37:10 AM11/21/21
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Hello,

I try to understand spectrum to analyze which files are the best quality.

Which os those is the best quality plz ?
Normally flac would be better but i see more red lines (bass ?) in the mp3.
Do i have to keep the most with red or the highest lines (even green or blue).
Flac version goes high but has lesss red the the mp 3.


Flac
flac less red.JPG

Mp3 with more red but less high in freq


mp3 more red.JPG


Thank you.

Richard Grant

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Nov 23, 2021, 11:08:52 AM11/23/21
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Hi there. Not sure this will help, and I'm only speaking from my experience.

From wikipedia on Spectogram, we have, a spectogram common format "..is a graph with two geometric dimensions: one axis represents time, and the other axis represents frequency; a third dimension indicating the amplitude of a particular frequency at a particular time is represented by the intensity or color of each point in the image."

So yellow/red colors are higher volume than green/blue/purple.

In terms of quality, and assuming the question has to do with an original highest quality source encoded to lower qualities, I look for the file with the highest frequency.

In the example you provide, you can see that the mp3 peaks at a lower frequency than the flac. Also, if you observe the peak frequencies of the mp3, you will see the somewhat loud green frequencies abruptly terminated in the mp3. There is more of a fade to higher frequencies in the flac file. And finally, the more intense colors in the low end could be the result of the known muddy effect introduced by lame encoding.

In cases where the files are not from equal sources, you may see greater loudness due to DSP effects like wavhammer that bring more quiet sounds from the background into the foreground, and it is a matter of taste at that point whether the louder potentially lower peak frequency file is better quality or not.

In short, loudness does not mean more quality, except when it does.

R
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