Sound file formats and sound quality

Good Afternoon,

I am wondering if when copying a segment or a clip of a track, does the copied clip have a reduction in sound quality? Or when saving a copy of a mp3 file, is there a reduction in the quality from the original?

I found this thread:

and I wonder what is the best format to work with and edit in audacity that will save quality of sound? I have access to a few flac files or .rm or mp3 files. Or would converting a mp3 to flac or wav work?

Thank you.

Ayesha Nicole

There is not normally reduction in sound quality when copying / pasting within Audacity.

There is always loss of sound quality when exporting as MP3.


Audacity always works with high quality uncompressed PCM audio internally.

Converting from MP3 to WAV or FLAC does not improve the sound quality. It’s a one way street - converting to MP3 (or other lossy compressed format) reduces sound quality.

One more thing in case it’s not clear…

Audacity (like all “regular” audio editors*) decompresses the audio when you open the file. If you open and edit an MP3 (or other lossy file) and then re-export it as MP3 (or other lossy format) it’s going through a 2nd generation of lossy compression.

If you save to WAV or FLAC, there is no additional quality loss.

Ideally, you should compress ONCE as the final step if you want a lossy format. Otherwise, try to minimize the number of times the data is lossy-compressed.

*There are some specialized editors (such as MP3DirectCut) that can do some limited MP3 editing without decompressing first.

Thank you. When I download a mp3 file and work with it, and then export it again as an mp3, does it lose another ‘layer’ of sound quality? Similar to making a copy of a copy of a copy of an image?

I have a very large personal project, that will eventually be shared with many others, and it will become the norm for this particular usage; and there are many mp3 files available; but I am thinking that if I can actually locate and purchase the studio quality cd’s, and rip them and edit in audacity, it may be the best for sound quality, in the long run. I am trying to plan very well before I start, and streamline the process to train others to help with it, because it is extremely labor intensive.


The amount of loss depends on the MP3 encoding settings. Higher “kbps” loose less than low “kbps” but at the cost of greater file size - that’s the trade-off “quality:file size”.

Exporting as FLAC. WAV or AIFF will reduce the loss to almost nothing. This is like having a near perfect photocopier.

Exporting as 32-bit float WAV will reduce the loss to zero. This is like having a perfect photocopier, but the down side is that 32-bit float WAV files are huge (double the size of a normal WAV file), and not many applications support 32-bit float WAV. Normal 16-bit WAV (or FLAC) is good enough for just about everything (except perhaps scientific research).