Export size

I used to export a 30min recording with a MP 3 size of 6MB With the new release the size is 34 MB What am I doing wrong

The size of an exported MP3 is a trade-off against sound quality. Smaller files are achieved by increasing the amount of compression, but this also reduces the sound quality. Less compression gives better sound quality but larger files.

Older versions of Audacity had a default MP3 format of “128 kbps CBR”. This was the de facto standard for on-line music in the late 1990’s (when modems were slow and disk space was expensive). 128 kbps CBR is generally considered to be “reasonable” quality for stereo music.

In line with Amazon, iTunes and other major distributors of on-line music, Audacity is updating its default setting for MP3 to higher quality.

“Preset Standard” is recommended for “good quality” stereo music. It has a bit-rate of about 200 kbps (it varies automatically between about 170 to 210 kbps depending on the requirements of the audio).

The “CBR” settings are recommended for Podcasts and audiobooks.

Higher “bit-rate” (bigger “kbps” number) gives better quality and larger files, Lower bit-rate gives smaller files but lesser sound quality.
Note that the loss of sound quality after MP3 compression can not be recovered - always keep a high quality WAV or FLAC format backup copy of all important recordings.

See here for how to change the settings: http://manual.audacityteam.org/man/file_export_dialog.html#options