I couldn't agree with Tpreaves more. The only way to achieve a good balance with timber and audio transition from front to back or sides to front is to operate with the same speakers. I would go even further and say all the speakers should really be the same speaker.
For example, I'm using monitor audio GR20's for my fronts
GR10's for the rears, GR center, GRFX for the sides. They all have the same 6.5" driver and 1" tweeter.
For example, I'm using monitor audio GR20's for my fronts
GR10's for the rears, GR center, GRFX for the sides. They all have the same 6.5" driver and 1" tweeter.