BASS_CONFIG_DEV_NONSTOP config option
Do not stop the output device when nothing is playing on it?
|nonstop||If TRUE, sample data will continue to be sent to the output device while nothing is playing.
By default, BASS will stop sending data to the output device when nothing is playing, to save a little CPU. When that happens, the device buffer will become empty, and the next playback will begin more quickly as a result. Or it may be delayed if the device has gone to sleep in the meantime. If more consistent playback latency (around the value given by BASS_GetInfo) is wanted, this option can be enabled to keep the device buffer filled with silence when nothing is playing. The output will still be stopped by BASS_Stop then.
BASS_GetConfig, BASS_SetConfig, BASS_CONFIG_DEV_BUFFER