Scientific research proofs: Noise makes sick! But what exactly is that noise?
1. Noise within rooms is reflected from all hard surfaces like walls, ceiling, floor and other items in the room.
2. This cause echo, because sound travels at a certain speed. Each reflection increases the way length and we can hear this echo later than the previous one. Many echoes follow each other in different loudness.
Your brain gets stressed, because it must separate all the echoes, in order, that you can understand, what is said. In practise you may ask your colleague to speak louder, so you can understand him. Everybody is speaking louder, most often unconsciously and the room gets filled with lot of noise.
Your brain and ear decreases its ability to hear soft tones. It filters them out and you are only receptive to the loud ones. A very bad situation, which is like you can see the world only in black and white. Your full ability to be aware and awake to your environment is gone. Your productivity will decrease likewise.
A simple way to enhance your room's acoustics is to replace as many reflecting hard surfaces with absorbing material. Sound which hit on absorbing surfaces does not get reflected so much. Echoes will decrease or even diminish mostly and you can hear silent speech very clearly. Everybody can speak more silently and still get understood very clear. Stress is decreased - productivity and feel good is increased.

An important issues on almost all sound absorbing materials is, that they need a buffer distance to a hard surface like walls, ceiling and other parts. Due to the long wave length of lower tones a thin sound absorbing material, which is applied directly on hard surface does not absorb much. While the same material applied with a distance of minimum 30mm to 150mm absorbs very well.
Same happens with acoustic material in the middle of rooms. Without a buffer the sound absorption may not be as good as promised. In practise this applies to partitions, which often do not have a significant effect.
Generally speaking, a more detailed knowledge is valuable to evaluate the sound absorption of a specific product and where it is applied within the room. It may be a good product, but may unfold it's full absorption feature only if applied in a certain way. Otherwise it can happen that it is almost useless.