Background noise like bubbles when exported file as MP3


I’ve just downloaded Audacity 2.0.4. I have Mac OS 10.6.8. I was previously using an older version of Audacity and heard a background bubble type noise when I exported my file as an mp3. Has this problem now been resolved? I’d like to know before I re-record. It’s a 14 minute 3 track (music intro and outro with a vocal track) that Audacity compressed to 2 tracks when making the mp3.

I look forward to hearing back from someone. Thanks!

Without reading between your lines, you may have chosen a lower than required MP3 quality value. When you export to MP3, 64 is the lowest value that you can possibly use for a stereo show and 32 for mono. Those two numbers will give you a barely acceptable show on your iPod of other Personal Music Player. Higher is better. Audacity defaults to 128 for a stereo show which is good, but not excellent. For almost perfect MP3s, choose 256 or 320. Please know that the file sizes are going to go up every time you increase that number.

Please know that if you’re editing an MP3 file such as an internet download those numbers no longer work. 256 or 320 are required in that case. MP3 sound damage goes up, sometimes a lot, every time you make a new one.

If you’re just cutting off the beginning and end of a song, you might consider one of the pure MP3 editors rather than Audacity. I don’t know of such an editor for the Mac.

Our normal choice may be available for the Mac. Look here:

You will not be able to apply fancy effects or filtering. Those require that you make a new MP3.


Hi Koz,

Thanks for responding. I recorded original vocals on Audacity using the sound settings that were default for a new file. I’m not very technical so I just hit the record button and recorded. The whole recording including the music tracks sounded fine. The problem was when I exported the file as an MP3 - formerly it was an Audacity file. Where do you put the number for mp3 quality? There wasn’t any option like this in the old 1.3.13 version. The music tracks are from a copyright free mp3 recording that I downloaded into my itunes.


In Audacity 1.3.13, MP3 Export Quality was set in Audacity > Edit > Preferences. We long since changed it to an extra step during the actual Export which is where most people expect to find it.

It’s actually compression bitrate expressed in kb per second, but many people just know it as the MP3 quality number.

The music tracks are from a copyright free mp3 recording that I downloaded into my itunes.

You may be listening to the music bubbling behind your voice. The music part of the show has been through two different MP3s, one from the internet and one you made in Audacity. That part of the show is going to accumulate damage even if your voice is crisp and pure.


In the Export dialogue screen, select “MP3” as the file format and then click the “Options” button: Audacity Manual