M/S Stereo is a stereo coding method that separates a stereo signal into two channels: mid and side. The mid channel contains the information that is common to both speakers, while the side channel contains the information that is unique to each speaker.
This can be useful for a variety of purposes, including:
Enhancing the stereo image: By adjusting the levels of the mid and side channels, you can create a wider or narrower stereo image.
Creating spatial effects: You can use the side channel to create the illusion of depth or movement in a mix.
Reducing mono compatibility: M/S stereo signals retain their stereo information even when played back in mono.
How M/S Stereo Works
M/S stereo signals are created by using a matrix to separate the left and right channels of a stereo signal into two new channels. The matrix uses the following equations:
M = (L + R) / 2 S = (L - R) / 2
Where:
M = Mid channel
S = Side channel
L = Left channel
R = Right channel
The mid channel is simply the average of the left and right channels. The side channel is the difference between the left and right channels.
Mid Channel
The mid channel contains the information that is common to both speakers. This includes things like vocals, bass, and drums.
Side Channel
The side channel contains the information that is unique to each speaker. This includes things like guitars, keyboards, and effects.
Using M/S Stereo in a Mix
M/S stereo can be used in a variety of ways to enhance a mix. Here are a few examples:
Widen the stereo image: To widen the stereo image, you can increase the level of the side channel. This will create the illusion of more space between the speakers.
Create spatial effects: You can use the side channel to create the illusion of depth or movement in a mix. For example, you could increase the level of the side channel for sounds that are supposed to be coming from behind the listener.
Reduce mono compatibility: M/S stereo signals retain their stereo information even when played back in mono. This is because the mid channel contains all of the important information that is needed to create a good mono mix.
Conclusion
M/S stereo is a powerful tool that can be used to enhance a mix in a variety of ways. By understanding how M/S stereo works, you can use it to create mixes that are more engaging and immersive.