Piecing together surround on the cheap (1 Viewer)

[NoHairHere]

I am new to all of this so thanks for your time and any expertise you all can share. I am starting to piece together a 7.1 system on the cheap, by adding the right parts where I can find them - ebay, letgo, CL, GoodWill, etc. I am starting with a BA CRC7. I dont have a receiver yet either. My question is what do i look for in regards to the front speakers, rears, subs to ensure they compliment one another and are balanced? For example, i see a pair of Polk Audio R10s for sale. What info in the specs of these would tell me where in the configuration they might be best suited?

Thanks to all for your guidance!

 

[Todd Erwin]

This article is a good place to start:

A Beginner's Guide to Home Theater