Mid-Side
Deriving stereo from mid and side signals, with width adjustable at the matrix
Related
Mid-side uses a forward-facing mid microphone and a sideways figure-8 side microphone, then matrixes the two signals into left and right. The two output channels are the sum and difference of mid and side, so the side channel sets the width.
Its great advantage is mono compatibility: the mid signal alone is a complete mono picture, and the side can be faded at will. Width can also be changed later by adjusting the ratio, without moving microphones. The side mic must be figure-8 and should sit as close to the mid as possible; check polarity and time alignment first.
The usual mistake is treating mid-side as a phase trick. It depends on real sideways pickup; a wrongly aimed or displaced side mic skews or even cancels the decoded image.
Sources
- 中侧矩阵与立体声拾音，参 Huber & Runstein, Modern Recording Techniques 与 Bartlett, Practical Recording Techniques；本文为原创表述
Used for fact-checking only; all prose is original.