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
Belt? It’s like 101 on a cassette player..
MC got it... Clean and inspect..
Retention your tape.
Go all the way one way AND all the way the other high speed of course.. It helps.

I like cassette, don’t like the play back to much, though.. :-)

I’ll put one in the playback rack.. Tascam for cassette, Otari for RtR
Both affordable and available..

Regards
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.