MP3 Export Quality

[caligari]

I use Finale 2010 to compose music and the exported .wav file from that program is very acceptable. But sometimes I need to use Audacity for some tweeking. When I export to MP3, the quality is distorted, i.e., girgles in sustained tones. I'm using Audacity 1.3.9 beta. How do I resolve this quality problem? How do I upgrade to a later version?

[steve]

When I export to MP3, the quality is distorted, i.e., girgles in sustained tones.

MP3 is a "lossy" compression format http://en.wikipedia.org/wiki/Lossy_compression
There is always some degree of sound quality loss when encoding as MP3

How do I upgrade to a later version?

Download Audacity 1.3.12 from here: http://audacityteam.org/download/
Just install it over the top of your previous version.

Locate the Lame file that you are currently using (for MP3 encoding) and install the new version from here: http://audacityteam.org/help/faq?s=install&i=lame-mp3

WAV is an uncompressed format and unlike MP3 will not reduce the sound quality. If you need to compress the file as MP3 (for example to make it smaller for sending by e-mail or playing on an iPod) set the MP3 encoding to a higher quality setting. To do this, when you Export and select MP3 as the file format, click on the "Options" button.
Preset "Standard" will produce reasonably good sound quality. Preset "Extreme" will give excellent sound quality with virtually no audible difference from the uncompressed format.

Note that MP3 damage is permanent and irreversible. Re-compressing an MP3 file will always increase the damage, so keep your audio in WAV format while you are working on it. If you need MP3 for the final "product", encode it as the last step.

[caligari]

Thanks! That clears up a lot.

[kozikowski]

There are fuzzy values, too. 32 is the threshold for mono shows. Below that, most people can tell there's something wrong. 64 for a stereo show. 128 is a good overall stereo show with some really minor damage. I think there's a higher value of 300 or 360 where you would need expensive instruments to tell where the damage is, but there is always some. MP3 and the other compressed formats are destructive and are intended as the delivery step, not a production step -- unless there is no other way. They are a dead end.

Koz

[bgravato]

I think there's a higher value of 300 or 360 where you would need expensive instruments to tell where the damage is, but there is always some.

It's 320 kbps. Though I consider 192 kbps to be very acceptable. Using variable bitrates rather than constant might give you a better quality at the same file size.

Amplifying to a peak amplitude slighty lower than 0dB might avoid some clipping that sometimes occurs when exporting to lossy formats.