Learn what mid side micing is and how you can use it to record stereo audio.
Though most people understand what stereo means in terms of the home audio consumption model, it is difficult to conceptualize how it is recorded. Most audio is recorded in a simple mono set up where even multiple tracks of audio are essentially recorded the same. The reason for this is that recording stereo is not just a matter of placing different mics and using different sources, but instead an entire micing method that requires special set up and mixing. The mid side micing technique is one of these ways to record stereo audio.
Preparing for Mid Side Micing
What mid side micing does is allow you to record stereo by recording two different channels when recording audio. Take two microphones to record channels. The first should have a standard side figure eight pick up pattern. The other microphone should have a regular cardiod pick up pattern. The cardiod microphone will act as the mid mic and the figure eight will be the side. This is the standard set up for mid side micing, but many people will supplement an omnidirectional microphone for the cardiod microphone, but only do this if it is actually more convenient because recording with a cardiod as the mid mic is safer. From here you will need a digital recording system to record the audio, and a 702 field recorder may be a good option for this. The 702 kit does have the settings pre-built in to handle mid side micing stereo recording, so go for that or a comparable one if you can.
Recording With Mid Side Micing
Take the cardiod microphone and put it in normal forward recording position. Take the figure eight microphone and place it at a ninety degree angle to the cardiod microphone diaphragm area. Make sure you take your field recorder and router each microphone to separate channels to record on. You will now record the audio like normal and then alter it during the audio post-production process in a program like Pro Tools 8.
Take the side microphone audio and put it onto its own track. You will then invert the audio so that the phase is correct. Take the audio from the mid microphone's track and pan it to the center. Take the original audio from the side microphone and put it to one side, and then put the inverted version of that same audio to the other side. Now you can alter all three tracks to your liking including effects and volume, which are standard for audio post-production.
Mid side micing is not the only way to record stereo audio, but for many people it is one of the easiest. What makes it useful is already having good microphones, audio recorders, and post-production software like Pro Tools 8. You have to use all of these elements to make it work, but once you get the process down it may become your first choice.