One of our teachers does a sound absobtion practical every year. A buzzer sits in a box surrounded by foam/paper/bubble wrap/ etc. A decibell meter is placed close by and readings taken for several thicknesses of insulation. The prac rarely works due to backgrond noise.. Other students apparatus. The teacher has considered putting the meter in the box, but like schrodingers cat it cant be observed. Does anybody have a way to do this... I can buy datalogging sensors, but I only have 3 interfaces and 4 computers.... We are looking into using mobile phones with monitoring apps, but I'm not convinced.