Why do my backspeaker allways play both, even when I test ballance left right?

More info is needed to answer that like stock, aftermarket, amp model # and how it's all configured. Having the rear mixed mono is not such a bad thing like most would think. What matters is proper attenuation & limited bandwidth so that it does not detract from the front stage & sub.To achieve a true surround sound in a vehicle some sort of processing (most likely outboard unit) would have to be utilized.

Other than that, the most to be expected is some added ambience.

Make shore that there nit wired in parallel that also is possible about a sub channel.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.