There is none on the album.
Real sibilance is due to a lot of energy in the 3000 Hz region where our ears are most efficient. It is also a region where a lot of rooms cause trouble. Female voices and violins are frequent affected. If you have the capability putting a 2-3 db filter between 2500 and 4000 Hz will magically make sibilance disappear.
The usual culprits are speakers, rooms and the interaction between the two. You can see this on a frequency response curve which can be easily generated with a computer and measurement microphone. You can also see the results with added sound deadening.
