For best quality I recommend that you try using the "--alt-preset" switches for encoding.
"lame.exe --alt-preset standard " is considered to offer the best quality/filesize ratio, so it is recommended that you try this first.
However, if you are interested in the other modes, here is a dump of the "--alt-preset help" switch:
The --alt-preset switches are designed to provide the highest possible quality.
They have for the most part been subject to and tuned via rigorous double blind
listening tests to verify and achieve this objective.
These are continually updated to coincide with the latest developments that
occur and as a result should provide you with nearly the best quality
currently possible from LAME.
To activate these presets:
For VBR modes (generally highest quality):
"--alt-preset standard" This preset should generally be transparent
to most people on most music and is already
quite high in quality.
"--alt-preset extreme" If you have extremely good hearing and similar
equipment, this preset will generally provide
slightly higher quality than the "standard"
mode.
For CBR 320kbps (highest quality possible from the --alt-preset switches):
"--alt-preset insane" This preset will usually be overkill for most
people and most situations, but if you must
have the absolute highest quality with no
regard to filesize, this is the way to go.
For ABR modes (high quality per given bitrate but not as high as VBR):
"--alt-preset " Using this preset will usually give you good
quality at a specified bitrate. Depending on the
bitrate entered, this preset will determine the
optimal settings for that particular situation.
While this approach works, it is not nearly as
flexible as VBR, and usually will not attain the
same level of quality as VBR at higher bitrates.
The following options are also available for the corresponding profiles:
standard
extreme
insane
(ABR Mode) - The ABR Mode is implied. To use it,
simply specify a bitrate. For example:
"--alt-preset 185" activates this
preset and uses 185 as an average kbps.
"fast" - Enables the new fast VBR for a particular profile. The
disadvantage to the speed switch is that often times the
bitrate will be slightly higher than with the normal mode
and quality may be slightly lower also.
"cbr" - If you use the ABR mode (read above) with a significant
bitrate such as 80, 96, 112, 128, 160, 192, 224, 256, 320,
you can use the "cbr" option to force CBR mode encoding
instead of the standard abr mode. ABR does provide higher
quality but CBR may be useful in situations such as when
streaming an mp3 over the internet may be important.
For example:
or "lame --alt-preset fast standard