BASS_CONFIG_MIXER_POSEX config option
How far back to keep record of source positions to make available for BASS_Mixer_ChannelGetPositionEx.
|length||The length of time to back, in milliseconds.
If a mixer is not a decoding channel (not using the BASS_STREAM_DECODE flag), this config setting will just be a minimum and the mixer will always have a position record at least equal to its playback buffer length, as determined by the BASS_CONFIG_BUFFER config option.
The default setting is 2000ms. Changes only affect newly created mixers, not any that already exist.