Good evening , when I apply the effect amplifies on a full track and do export to mp3 , apparently does not save the changes because if you re- open the track volume is like the original and if you re- apply the effect amplifies me the same value that gave me the first time on the original track . I hope I explained well enough . Thank you all.
How much are you amplifying it by?
Do you hear the change and see the change in the waveform before you export?
Maybe you’re re-opening the original MP3, or the wrong one??? Try using a different file name, and try a BIG change, like -20dB.
MP3 export is lossy and does not preserve the maximum peak level exactly.
If you need any more help please tell us what version of Audacity you are using (all three numbers, see the pink panel at the top of the page).
I tried to make a new file instead of overwriting and it works. I do not know what the problem might be. The version of Audacity is 2.1.2
Audacity renames the original MP3 file with a “0” suffix while overwrite-exporting. Sometimes when overwriting, that original MP3 can get left behind. If you inspect that original file it will obviously be unchanged.