We are all familiar with suspended ceilings which have various styles and sizes of ceiling material set within the thin metal grids. There are also very similar systems where a suspended grid of metal is hung from a ceiling onto which drywall is attached. These are sometimes referred to as acoustical drywall ceilings. The grid may be used where the original ceiling is irregular and not flat. By hanging the ceiling grid at a common level, the ceiling can be made mono level.
The benefit of this system is that it simplifies the design and improves the appearance of the area where the ceiling is being installed. This system also is useful to reduce sound transmission from floor to floor. When a drywall ceiling with living space above is mounted directly to the floor joists above the combination of the floor above and the ceiling mounted between studs forms a sound drum. By suspending the ceiling, the drum configuration is eliminated.
The suspended drywall ceiling system is useful in basements, apartments, dorms, schools, hotels, and other public buildings, etc. You can learn a great deal more about how to use a suspended drywall ceiling from your local professional, drywall installer/trade contractor.