the simple stuff

Sound fills the air all around us, and our ear is working all the time to filter out unimportant sound from our consciousness so we can pay attention to the important information. This means that we are largely unaware of how much sound surrounds us at all times. If you concentrate on what you hear, you will find that silence is very hard to find. A microphone does not have an intelligent filter, so it will pick up everything (depending on how sensitive it is). By carefully preparing your recording environment, you can eliminate a lot of the background noise that might otherwise spoil your soundtrack. Getting a clean recording at the outset will mean less work trying to fix problems later.

Your microphone should be suited to your recording equipment and to the sort of recording you are doing. Poor quality equipment or a noisy environment will introduce noise into your recording, interfering with the signal that you are trying to capture. Basically, signal is what you want, noise is the sound you don't want. An omni-directional mic picks up sound from all directions and is good for recording background noise, music from several directions, or several people talking. A uni-directional mic is pointed at the sound coming from a single source - one speaker, one instrument, etc. Clip-on mics can do a great job recording individuals in conversations because they are placed so close to the person's mouth, but if you have more than one or two participants, you may need to think about mixing sounds from multiple mics to control different sound levels. Table mics are nice for several people sitting around a table but will pick up the sound of someone touching or bumping into the table, shuffling papers, etc., so subjects need to take care if you use these. Microphones that are built into a tape recorder or camcorder tend to pick up machine vibrations from motors (more noise) and are difficult to place close enough to a subject. A long microphone cable may act as an antenna that could pick up static from fluorescent lighting or even a local radio station.

If a microphone's specifications include "signal to noise ratio", a high signal to noise ratio will sound best. Another way to improve your microphone's sound is to use a pre-amp (see below).