The extended input buffer guards the recording against skipping during the longer periods of high disk drive or CPU activity. The event will trigger when the size of the data in extended buffer will exceed ExtendedBufferTime/2. The event is triggered once for each set of buffers for all channels. Typically the event would contain code like this: 

//    SignalMux.Inputs := AsioAudio;
//    SignalWrite.Inputs := SignalMux;

SignalWrite.Pull;  //write data to file

published