What to Do With Polk R15??

[pachuco4life]

First off I I am a total noob when it comes to audio/ Home theater. This is my first post, but have been reading these forums for a while and have learned a lot, so I thank you.

I am putting together my first surround sound, which can't be too big because I live in an apartment . I have a pair of Polk R15's I want to use in the set up and was wondering where I should have them located. I just ordered a pair of Polk Monitor 60's and a cs2 center. Should I use the R15 for left and right surrounds or rear surrounds in a 7.1 set up? I will need to order two more speakers(down the road) for the set up and was looking @ the Monitor 40's for sides then using R15 for the rear. Would the M60's, cs2, and M40 drown out the R15's? BTW I am using an Onkyo 705 receiver if that matters. Thanks in advance.