Good day.
Running version 2.1.0
I need guideline to clean noise in mp3 file.
Thanks.
The current Audacity version is 2.1.3 and you can get the Windows version from here.
I need guideline to clean noise in mp3 file.
Audacity is not recommended for cleaning MP3 files.
Any time Audacity works on a sound file, it has to make a new one when it’s done. In the higher quality formats like WAV or AIFF, that’s not a big deal, but in the compressed ones like MP3, the new MP3 file will be a lower sound quality. If the MP3 file was already a low quality, Audacity may trash it when it makes a new one.
Koz
Greetings,
What software you recommend.
Thanks.
I think what Koz means is that it is better to work with high quality “uncompressed” audio rather than MP3.
The MP3 file format “compresses” the audio data to make the files smaller, but in doing so it discards some of the audio data and causes a small amount of damage to the sound. Further processing of the audio after MP3 encoding can only make that “damage” worse - you can never get back the data that was discarded.
Re-encoding an MP3 is like making a photo-copy of a photo-copy in that the quality gets worse with each new generation.
Audacity’s Noise Reduction can be use with MP3 files, but you need to be aware that MP3s are decoded when imported into Audacity (which is necessary for audio processing), and then if you export as MP3 it is re-encoded, causing additional sound quality loss.
If you start with a high quality MP3, then the cumulative damage may not be noticeable, but with a poor quality MP3 the results are likely to be poor.
Instructions for the Noise Reduction effect are here: http://manual.audacityteam.org/man/noise_reduction.html
Great information.
Well, I have original source in mp4, I may export sound to any format using format factory.
What format you recommend, and what steps I need to do my job.
Thanks.
MP4 is also a “lossy” format, so not an ideal starting point, but if that’s all you have then you can only use what you’ve got 
If you have FFmpeg installed, you can probably import the audio from the MP4 directly without converting to an intermediary format.
If you don’t have FFmpeg installed, see here for how to install it: http://manual.audacityteam.org/man/installing_and_updating_audacity_on_windows.html#winff
what steps I need to do my job.
The tools can change with the job. Please post a sample of the damaged sound.
https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1
Koz