How is stereo recording done?
Stereo recording uses various stereo techniques to produce a recording, like a CD. There are different aspects in technique to consider when preparing to record stereo, like microphone techniques, placement, choice.
Each of these sections of stereo technique has an impact on the resulting audio. Some have more, some less, but they make a difference.
This article is meant to be a basic primer, and will focus attention to the various aspects of it. For an introduction to the idea, such as why we want to record in stereo, see the Stereo Recording Intro.
We will look at:
- Microphone techniques
- Microphone placement
- Microphone choice
Let's look at some of these things...
(If you're new to recording and want to get a better handle on things, check out the recording process page.)
Also, there is another article on choir recording that you should check out if you are interested.
There are a few standard methods of recording in stereo. They operate from a few basic principles of physics, or how sound behaves.
The main difference between any stereo recording technique is whether it focuses on time differences or on volume differences.
If you set two microphones down, one foot apart from each other, any sound that is not coming from directly on center will arrive at one microphone before the other. Our brains can process these minute delays, forming a soundstage, or image of where the sound originated.
Level differences are different - they require directional microphones (where omni-directional mics work well for time difference). The diaphragms are placed together, as close as possible, but pointed in different directions. When a sound comes from off center, it will seem louder from the mic that is pointed in that direction. This is another way that our brains can decode a stereo recording to make the soundstage.
Branching from here, there are ways of combining the techniques to get better sounds yet, and specific instructions on how to implement them. See Stereo Mic Techniques for more the detailed discussion on this.
Where you place the microphones makes a big difference in stereo, as it does for any recording. It really takes some experience to hear this, so you need to try it on your own, but here are a few principles to keep in mind.
First, the blend. Any ensemble sounds more blended the further you go away from them. The bigger the group, the further away you need to be before you will have a nice blend of everything. The closer you go, the more you risk hearing individual voices, or losing the cohesive whole sound of the group.
Second, the mix. A recording is made in some sort of acoustical environment, and you need to balance the recording between the sound of the source (be it a choir, orchestra, or other ensemble) and the room reverb.
And don't forget, keep the stereo image centered - don't let the sound become skewed to one side. Your listeners will thank you. :)
See Stereo Mic Placement for more discussion on this topic.
You need some large scale framework to select mics. What kind of group will you record? Is it a choir, and if so, what size, and will they be accompanied? Or is it a small orchestra?
It is important to consider what technique you will use, such as time or volume difference (XY, AB, ORTF, etc. - see Mic Techniques ). Your strategy will dictate what mics you have to choose from.
For more on the selection strategy, see Stereo Microphone Selection.
So stereo recording can be a lot of headache, but it is a lot of fun.
Do you have stereo recording questions? Trouble making sense of all the jargon or ideas? Trying to decide what equipment to use in which pattern? I'll be glad to help you, however I can. I see every question that comes in, and will do my best to answer your stereo recording questions.
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