Hi,

Recording large amount of audio always requires a proper selection of
sampling frequency and bit rate to optimize storage and quality of the
recording. A precise and more sophisticated approach is to use AQuA
Wideband, but when you need a quick advice on what sampling rate and
bit rate to use for your podcast, meeting recording, conference
speech, audio book or other large amounts of audio signal Audio
Compression Adviser is the product that gives you proper parameters
for your MP3, OGG, AAC encoder.

Give it a try with this online demo, provide UNCOMPRESSED .WAV (note
the online demo accepts files only less than 5Mb ), set how much
quality you like to preserve in the compressed audio in percentage and
click "Advise!" button. After the file is uploaded you will see
recommended sampling rate and bit rate for your audio within a couple
of seconds!

http://www.sevana.fi/audio-compression-advisor.php