engine noise. help needed

Hi everyone. I’m new in the sphere of ATVs. It is my first quad (polaris sportsman 550 / 2010.). I bought a used one. Now a strange noise appears from under the seat. I found that the belt was replaced in 2011. Can it be the sound of the belt. Here is the link of the sound it produces.
Vocaroo | Voice message
would be extremely thankful to your advice.