For a center channel, one wants to have only those signals that are common to the left and right channels. (It's a little more complex than just summing but similar.)
However, by connecting the speaker between the two hots means that current will flow only when there is a voltage difference between the two hots. Thus, it will reproduce a difference.
Playing and placing such a speaker between the left and right will not fill the middle but, rather, increase the effective separation.
However, by connecting the speaker between the two hots means that current will flow only when there is a voltage difference between the two hots. Thus, it will reproduce a difference.
Playing and placing such a speaker between the left and right will not fill the middle but, rather, increase the effective separation.