I would assume that the easiest solution is from a surround speaker from the same manufacturer as the L/R/C speakers. Ideally, it would be the same speaker as used in the fronts.
I guess I don't fully understand what you're asking, so if that doesn't answer your question please clarify what you're looking for.
Michael
I guess I don't fully understand what you're asking, so if that doesn't answer your question please clarify what you're looking for.
Michael