:?: I need to know why my exported files are always larger than the original, even if I don't do anything.

This has been a frustrating problem for a while now. I mostly use audacity to make minor edits to songs, such as cutting out a section I don’t like, creating a fade in/out, or in most cases, cutting out a little bit of silence at the beginning/end. The songs are in MP3 format from the beginning, and I also export them as MP3. I find that even if I simply open up a song, do nothing, and export it as MP3, the file size still increases by 25-50%. You’d also think that cutting a file and making it shorter would decrease the file size, even if by a few bytes.

I don’t know if this has a fix, but I would like an answer as to why this is happening. Whenever I export, it says “Exporting the file with the standard preset” which to me means it wouldn’t change anything like the bitrate, volume, etc. If there’s some kind of setting that I need to change, then please let me know. Thanks.


There’s an mp3 quality setting:
better quality => bigger file.

NB: Making an mp3 of an mp3 in Audacity (even if you use the highest quality) will introduce generation loss.

If you want to edit mp3 without generation loss see … https://en.wikipedia.org/wiki/Mp3DirectCut

FYI - The bitrate in kbps is kilo_bits_ per second. There are 8 bits in a byte so if you know the bitrate and playing time you can divide by 8 to get the file size in kilo_bytes_ per second. (This doesn’t include embedded artwork which adds to file size, unrelated to the bitrate.)

From reading off your MP3 export options link:

Because my files are in MP3, can I safely convert it to .wav, edit it in audacity, and export it in MP3 without generation loss?

Whenever I’ve had to do file conversions in the past, I’ve always just used online converters such as Freeconvert.com. Would that work fine, or can you recommend another tool?

Or, should I just use Mp3directcut instead? I’m used to audacity so I’d prefer to not do this, but If it’s the safest and easiest option, then I may have to use it.

Thanks for the help.

Because my files are in MP3, can I safely convert it to .wav, edit it in audacity, and export it in MP3 without generation loss?

No. It’s the recompression to MP3 that causes the quality loss. When you open a compressed file in Audacity (or any “regular” audio editor) it gets decompressed so it’s almost the same process if you convert to WAV first.

The “damage” happens when it’s compressed so there is no further damage if you export as WAV.

You may not notice any quality loss but it’s something you should be aware of and you should try to minimize the number of times it’s re-compressed.

MP3directCut is probably a better option if it does what you want. MP3directCut can cut, splice, and change the volume but it can’t apply “advanced” effects.

As above, you can probably get what you want by lowering the Audacity MP3 export quality slightly until the file sizes match. But also as above, If you started with a 192 MP3 and you export your corrections at 192, the new MP3 is not 192 quality. It could be as low as 96.

Have you ever corrected a song and had the correction sound a little cell-phony or like talking into a milk bottle? That’s why.

The straight MP3 editors may be what you want if you’re doing simple cuts and deletions. Those editors don’t take the MP3 apart to do that. The instant you need a fade, tonal correction, or fancy edits, you’re stuck with a real editor.


The “making an MP3” stage inevitably degrades the audio to some degree: MP3 format is an approximation.
The damage done may not be noticeable if you use the highest quality MP3 setting.

I would not use online converters: some sneak-in adware with the “free” download.

MP3 has been around for a long time. Its full name is MPEG1 Layer-3. It’s part of a very old video format.

It gets its small files by re-arranging musical tones and leaving quiet ones out. That’s why there’s no recovery. Once you make an MP3, there are parts of a song missing. Make an MP3 from that one and it deletes more tones.

Never do production in MP3.