I've ordered an acoustic ceiling which comprises a suspended ceiling with sound insulation above to absorb echo and sound insulate. I'm concerned because the builder has given us a sample of the tile today; I was expecting something of fibre which would allow sound to pass and be absorbed by the sound insulation but in fact he's offering gypsum.
Will a gypsum tile allow sound to pass through or will it reflect sound into the classrooms below and a fibre/alternative tile be preferable?