Audacity Forum

Hi,

I have recently downloaded and started using Audacity to edit MP3 recordings. When I edit out some portions of the recording and then export it as MP3, the file size becomes 3 times. Could you please direct me to the solution how I can keep or shorten the file size of the resulting MP3? I would appreciate it greatly.

Thanks,
Khindaria

Audacity will not directly edit an MP3. It converts the MP3 to an Audacity internal high quality format and edits with that. When you want a new MP3, Audacity 1.3 offers you an MP3 export panel where you choose a new bit rate. If you choose a very high bitrate, then your new MP3 could be very much larger than your old one.

Choose a lower bitrate. MP3 > Options > Quality.

MP3 music quality depends on bitrate. As the file size goes down, so does the
quality.

http://www.kozco.com/tech/WAV-MP3.wav

32 is the lowest number for a mono show. 64 for a stereo show. Above about 160, many people can't tell there is any damage. Above 320, almost nobody can tell.

Koz

Hi Koz,

Thanks for helping me understand the process and in identifying what the problem was in the options with which I was exporting.

What I am trying to edit is a narration (conference call recording) and when I export the MP3 using 8 kbps and Joint Stereo options, it reduces the file size to half the original size. As is evident from your recording link, the voices do sound as if the speaker is speaking at a distance from the microphone (kind of resonating a bit), but overall it seems to be bearable. With 16 kbps, file size remains the same as the original MP3 I started with. I am unable to tell the difference in quality of the audio between 8 and 16 kbps.

Is there a general thumb rule that when exporting narrations one should use X kbps, when exporting a song one should use Y kbps, etc?

Thanks,
Khindaria

You can use Tracks > Stereo Track To Mono to produce a single sound channel instead of two channels -- a different channel for each ear. If your show is simple spoken word, then mono should be acceptable. A mono show will sound acceptable at half the bitrate of stereo.

There are no rules other than the ones I posted. Your final work is determined by the client listening.

There is one oddity. People assume that you can produce a much better show by restricting the quality of the show before you make the MP3. I don't think that's correct. MP3 (and most compressors, audio and video) work best by efficiently compressing a perfect quality, quiet, graceful and clear show. If you make the show sound muffled or lower in quality, then MP3 will try to produce a perfect muffled show.

Koz

Thanks Koz. You have been a great help. Really appreciate it.

Best wishes,
Khindaria

mm...useful info