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NuVerb
TDM User Guide
Appendix
6
Appendix
Mid/Side Stereo Decoding using the Stereo Adjust algorithm
MS (Mid-Side) stereo recording uses a front-facing microphone (usually cardioid) and a
coincident, sideways-facing figure-of-eight. By convention, the side microphone's positive
lobe faces audience left. The Mid and Side signals are mixed in an MS matrix decoder to
produce the left and right outputs of a standard stereo pair. The matrix is simple: the mid signal
goes equally to both output channels. The side signal is summed into the output corresponding
to the side microphone's positive lobe. The side is subtracted to the other output. The matrix
decoding can be done either before, or after, recording.
With a little care, the Stereo Adjust program can perform this matrixing in the digital domain.
1. Connect the Mid signal to the right channel input, and the Side channel to the left.
2. Set the ROTATION control to maximum right.
3. Use the BALANCE control to adjust the width of the stereo signal. — If the inputs are
connected normally, maximum right will produce Mid on both outputs.
Normally, the correct output is obtained by feeding Side to the left input and Mid to the right
as described above. If Mid and Side are not correctly assigned before decoding, the matrix will
appear to work, but the output channels will be out-of-phase. If you are using a digital source
where Mid is left, you must correct the assignments. As the FLIP'n'SWAP control precedes the
matrix decoding, if you have a digital source where Mid is left and Side is right, you can swap
the channels before decoding. Otherwise, you must physically swap the left and right input
cables on the digital interface.