What are the diverse environments on earth?

What is the ambient acoustic sound environment like on the International Space Station? How does it differ from room environments on Earth?

• The beginning of most Startrek episodes has this hallow-faint windtunnel sound, most likely the reactor core. What's the acoustic environment like on the international space station? Are there detectable differences (by instrumentation or human ear) on how audio traverses through the station? Is it anything like an "anechoic chamber"?

• Answer:

  Sound works the same way onboard the ISS as it does on Earth. The ISS is a fairly noisy environment.  In a microgravity environment there is no natural convection to circulate air, so fans are needed to move air in and out of pieces of hardware, in and out of racks, and in and out of modules. Sit next to your desktop computer and get it warmed up by playing a video game.  Listen to the noise as the fans kick in to cool it.  Now imagine adding about 60 computers to the room. There are also pumps and compressors in the ISS and they are noisy, as is the exercise equipment. Throughout the ISS, the noise level varies from about 58 decibels to about 72 decibels.  They've worked pretty hard to reduce that noise over the years.  The peak used to be over 80 decibels.  Some early crewmembers reported high frequency hearing loss.  Crew used to wear ear plugs a lot. The loudest part of the ISS is the Russian Segment.  Russian safety requirements were not as strict as US safety requirements.