This is a little technical, but before sending out thousands of mp3s, it would be good to have them in the most optimal format. I was wondering if there is a recommended MP3 bitrate for downloads?

320 kbs
192 kbs
160 kbs
128 kbs
are the most common

I grabbed this below off the iTunes store help desk?

"Purchased songs (via iTunes) are encoded using MPEG-4 Advanced Audio Coding (AAC) format, a high-quality format that rivals CD quality. Songs purchased and downloaded from the iTunes Store are AAC Protected files and have a bitrate of 128 kilobits per second (kbit/s). The purchased song should sound as good as or better than a 160 kbit/s MP3 file. Because the bit rate is lower, though, the AAC file takes less disk space than the MP3 file."

But 128 kbs seems a bit low. I tried to do this quickly in Garage band, which defaults to a recommended 160 kbs, and does not have an option to choose AAC or something, else, so I am not sure what the complete specs would be once processed. I could try Pro Tools or another program to get a more exact format that would be most optimal.

Any suggestions?

Thanks, Kevin