There are many fields in science and technology that require acoustical treatment. Testing new equipment before production, along with many other types of scientific experiments, require a quiet room for good test results.
First, the space needs to be isolated from outside noise using sound barrier materials such as mass loaded vinyl and Green Glue damping compound in the wall, floor and ceiling assemblies.
Second, soundproof rooms also require a sound rated acoustic door or acoustic door seals on an existing door, to block sound leakage.
The inside of the room will require sound absorbing wall panels or acoustic foam to reduce room reverberation, so microphones pick up sound from the object being tested, rather than sound from reflective surfaces.