Voice editing and recording drop-out

I am new to Cubase (I have vs 11.0.10) so please forgive me if the forum has mentioned these topics many times before. But I am experiencing various problems. The two main ones are:

  1. Cubase changes the voices when controlling playback of MIDI-attached Yamaha SX900 keyboard. This happens even when I have transferred all data to PC via USB memory stick. I assumed there would be a MIDI event list editor or some way I could re-code each track with voice it should be playing back (with the 9 voice digit code: xxx-xxx-xxx).

  2. When using the Yamaha SX-900 just to control the on-board HALion Sonic SE, it drops out of record, mid-recording.This coincides with what I can only describe as a loud crackle. And this same sound occurs during playback sometimes, but it keeps going. It sounds just like the PC is suddenly demanding huge computing resources which kicks Cubase off-course. But, surely, Cubase is designed to work with a standard Windows 10 PC (with 32 GB of RAM) doing what PCs normally do in the background. Just one thought, the PC has a mirror RAID pair - might that be factor, I wonder? I have disconnected the PC from the Net and have turned off the virus scanner.

Any help that anyone can give would be much appreciated. Thanks.