Why is there humming when recording Serato?

i am recording from mixer to mic plug on laptop… i am using serato, and audacity at the same time…

i cant get a good sound quality really, and there is a hummy/whistle noise in my recording…

tried adjusting volumes on mixer and audacity…

not sure how to clean it up???

serato does make the same sound through my speakers when the records are spinning and there is no track loaded… speakers are new, and clean. mixer is usually ok…

also tried to record on separate laptop… no better
any thoughts?

i am recording from mixer to mic plug on laptop

You should probably stop doing that. Those two connections are not compatible.
Scroll down to “Connections.”

http://www.kozco.com/tech/audacity/windowsRecording.html

Koz