Microphones for a basic natural history recording kit:
* Coat Hanger Microphone - special contraption used on Life in the Undergrowth
* Radio Mics
* Parabolic reflectors - for pinpointing sound
* What is Stereo Sound? A/B and M&S Stereo.
The coat-hanger set-up:
This is simply a rig of two personal mics (like Sony ECM 77s, ~£400 per mic, quite weather-proof) on a coat hanger. He used 2 in order to record in stereo. Each one had a small Rycote windshield (£20 for a pair of little black ones) - well worth getting.
Personal mics are omni-directional, so are great for very natural sounds, but bad if you have background noises like traffic or people. They pick up base/low frequency sounds well.
For small animals (ants) or small spaces (zebra rib cages) you can reduce the distance between the mics (bend the coat hanger). Then, when you play the recording back through speakers, it ‘opens up’ the sound - a good thing.
Never put the word ‘radio’ on a carnet (including radio video links). Instead call them ‘remote’ microphones. Anything that transmits a signal can get you in trouble!
British radio mics are only licensed in the UK. There are specific channels and frequencies that you are allowed to use. In the USA hire special US licensed radio mics, or you will be breaking the law. Richmond Film Services in the US are good for this, and on average the radio mics will cost £22 a day. If you use an unlicensed frequency you can have other people using it (such as taxi drivers and bootleg radio stations!). In very remote places you could get away with it.
These are basically gadgets for acoustic amplification, and the closest thing we get to a ‘zoom’ microphone. The ‘dish’ is cleverly made to focus all of the sound made by one animal into a mic, thus amplifying the signal. If you are pointing the parabola at a group of animals, you can place a stereo mic in the middle. Generally it is mono though.
You can record at two different sample rates: 44.1 kHZ (like a CD) or 48 kHZ (like digital cameras, DATs and digis).
A higher sample rate (48 kHz) means that you sample MORE, so is better - lower sample rates reduce the quality of the recording (but check which one your production will use to make post production go more smoothly!)
Recordings from the same place (with the same mics) over time can give a time-lapse effect.
What is Stereo Sound?
Stereo can be ‘A&B’ (Left & Right) or ‘M&S’ (Middle & Side). These two techniques use different microphones, so you need to decide how you want to record sound when you order the equipment! A&B is the most standard (and recommended by Chris). M&S is more technical and needs some real thinking about. However, it can be very cool as, by boosting the ‘S’ signal alongside the ‘M’ signal, you can effectively ‘open up’ the sound to stereo, in sync with a camera move (to realise that one person talking is actually in a crowded room). This is how the laughing hippos were recorded.