sound not coming out properly through headphones

just recently purchased the ddj-400. i can get sound coming into my headphones, but the songs are not playing properly. it almost sounds like an instrumental version at times. i can bearly hear the lyrics of the people singing. sometimes the sounds from the instruments play with some weird sound effect as well. but when when i switch the sound back to my laptop's default speakers the songs play normal again. i've tried different headphones and they're all getting the same problem