Where do one put a stereo expander in audio mastering chain?

Question

i put just before the limiter and limiter is the last plugin in my chain....

Answer 1

For broadcast applications that is most likely the correct placement.  

For PA (public address), it doesn't matter.  You could probably place it immediately before the final power amplifier (without a limiter).

For recording applications, I would put it on its own switched auxiliary or effects loop, before the main mix.

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