a speakers louder than b speakers

I have a Onkyo stereo receiver not a AV system just stereo only. The a speakers are Infinities. I just bought some more vintage Infinities they are hooked up to b. The a speakers are much louder than b speakers. I switched the a & b input but a speakers are louder. Yes the + & - are correct.

No idea, but it seems linke a nice system

It is great for music but it is no AV system for movies I like it Thanks

Onkyo and Infiniti...flashbacks...LOUD!

Could it just be the way the outputs on the head are set? I really do not know.