Recommended LAME
--alt-preset standard (~190 kbit/s, typical 180 ... 220)
--alt-preset extreme (~250 kbit/s, typical 220 ... 270)
--alt-preset insane (320 kbit/s CBR, highest possible quality)
For high quality on portable MP3 players, you may use "--alt-preset medium" (around 160 kbit/s). The medium preset is only available in the modified LAME3.90.3.
The difference between "--alt-preset standard" and "--alt-preset extreme" is seldom perceptible. Hence, the ideal balance between maximum sound quality and least file size is obtained using "--alt-preset standard". This is the most recommended setting.