While there is a lot of sound pollution in the uk and this is likely to get worse with airport expansion and the pointless HS2 rail connection. No longer will you be able to have that all important quiet walk in the woods.. yet there are a lot of interesting sounds that we just can’t hear with our ears, unless we have special microphones like hydrophones and contact microphones.
Hydrophones or underwater microphone.
These can be place into water to record sound as it passes through it. Water is more efficient and faster than air for sound travel. We have all heard whale song on a TV documentary or on relaxation CDs but what about the small creatures that live in ponds and rivers or rain fall? This is a good use for this type of microphone with under water snails, and larvae of the Mayfly that will be airborne during the month of may. More exotic creature can be found in seas and oceans but we have interesting wildlife on our doorstep so almost anyone can be involved and understand the natural history and wildlife around us wherever we are.
Geophones. I thought I would add this as a footnote as it may be of interest to you as it is me. As I am tempted to add some in the future.
These record seismic activity and vibration through the ground via a spike. I guess that they could also be used to record the movement of glaciers which is why they interest me. We don’t get many earthquakes in the UK just the occasional earth tremor and predicting these is almost impossible. But again a microphone that will allow a sound recordist the chance of capturing unique and sometimes violent natural activity.