Allan Jennings

I am new to Bandlab and cakewalk, When I export the sound is different to when I master. I don't add any effects and just use midi tracks which produces a neat clean tight sound, but the WAV and MP3 all acquire reverb and a hollow timbre. I have tried many combinations and it is the same whthter I split tracks busses etc. I feel I must be missing something and need to press a button or something in the console mode but honestly cant see where I am going wrong. Been at this for 3 days straight with no result. I see none else has this problem so I am sure its me not the software - so can someone tell me the secret? Rgds Allan Jennings