The AVR S660 does have the ability to drive KLH five speakers. With a speaker of that caliber, if you are planning on using more than two of them I would consider moving up our line of AVRs to something like the AVR-X3700H. Not only does it have the ability to get more out of KLH 5s but it also has pre-outs so you can add power amps at any time should you want to get crazy with volume levels SPLs speaker quantities in your home.