What is the construction of the doors? Most of the raised panel doors are just hollow, so not much sound proofing.

Tru-stile doors will provide you with a what you need. Use a 1 3/4" thick door so the panel is about 3/4" thick. This is adequate reasonable isolation since a door leaks sound around the edges anyway. A true sound resistant door would be a solid core flush door (no panel) a gasket at 3 sides and a drop seal at the bottom.

A good solid wood raised panel door can't be beat for sound proofing and for lasting.

Any solid door is more sound transfer resistant than a hollow core door and the additional thickness of a raised panel wood door is offset by the greater density and tighter joints of a flat pane MDF door and its doubtful that a raised panel MDF door is much better than an MDF flat panel door. To make these doors more sound transfer resistant requires the installation of a perimeter gasketing system.