The best way to combine 2 signals

At your risk.


Of course the simplest way may be to just connect 2 microphones is series or in parallel. There is impedance increase or decrease which can be a good thing. It has been tried suceesfully on various Pleiades experiments.


If no signal coupling between the 2 devices is needed and preserving the impedance with minimum loss then the best way on our planet at least must be the hybrid transformer. It can be seen on the great Cinema Engineering Hollywood books. This is how adding (mixing is a wrong term) consoles were made.


2 hybrid transformers can even create balanced in, balanced in balanced out.


Here is the Wikipedia article:
https://en.m.wikipedia.org/wiki/Hybrid_coil


Of course hybrids can make the best mic spliters too.