what does it mean if your cassette deck playback and recording sounds warbly?


what does it mean if your cassette deck playback and recording sounds warbly? I just got a brand new Tascam CD-A580, and my recordings and playback sounds shaky or warbly. 
leemurray2007
Cassettes might need to be fastforwarded and rewound a couple times to loosen them up, especially if they haven’t been used in a while. The casing might be binding up the reels, too.
I hope it dont have to send it back; it looks great, and plays cds as well. but, i dont want a defective deck.
@russ69 ok man. stop trolling my threads with negative comments. You are being a jerk