deleting unwanted sounds

im not even playing or recording anything and i have this annoying humming sound caused by changing instruments while not even recording. now i can get rid of it unless i shut down and start fresh. how do i remove it and where is it coming from

Need more info. What kind of MPC do you have? Standalone or controller mode? Are you getting the hum through headphones, speakers, what? Are those headphones, speakers, etc. connected directly to you MPC or to another device?

Yeah... what type of MPC, what are you recording, how many things have you tried, what levels do you have set for input/output

I had my record player stacked on top of a cassette console that caused a hum once. Just a reminder, might help someone out there. Keep machines off of one another.