The sound coming from my center channel speaker is very low compared to my two front speakers. If I increase the volume of the receiver to enable me to properly hear the center channel speaker, the front speakers become too high. If I reduce the volume to bring front speakers to a tolerable level, I can barely here the center channel speakers. How can I fix this?

My set up is Harman Kardon AVR 130, Athena ASF2 floor standing front speakers. I use a Paradigm Atom bookshelf speaker as my center channel but plan to replace it with Athena ASC1 center channel in the future.

I have set up the front speakers as large speakers in the receiver set up, as they are actually large flooring speakers. If I change it to small speakers in the receiver set up (changing the programming not the physical set up), would the front speakers be compatible with the center speaker? Thanks.