technical university of dresden in germany want to find out. dad john out and soy has created a set up that mimics the experience of traveling by automobile. he's investigating how we hear and perceive different sounds. the acoustics lab is completely soundproofed even the floor is insulated against noise the researches have to walk on a net that keeps the reflection of sound waves in this room to an absolute minimum so sounds can be measured with great precision the researches know that certain sound qualities bother us more than others. and since higher frequencies always draw our attention and that makes the more problematic temporal variations are also an issue we tend to be very sensitive to sounds that aren't constant but very. so if a sound or source of noise is highly variable like the sound of a train that passes every 15 minutes that tends to bother us much more than a continuous noise. sound is measured as the sound pressure level expressed in decibel so the higher the pressure caused by a sound wave the louder the sound the sound wav