Retrieves the current read speed setting of a drive.
|drive||The drive... 0 = the first drive.
If successful, the read speed (in KB/s) is returned, else -1 is returned. Use BASS_ErrorGetCode to get the error code.
|BASS_ERROR_DEVICE||drive is invalid.
|BASS_ERROR_NOTAVAIL||The read speed is unavailable.
Divide the speed by 176.4 to get the real-time speed multiplier, eg. 5645 / 176.4 = "32x speed".