20 foot long speaker cable: is it ok?

Hi guys I'm looking to move my speakers to the long wall of my room, the 14 foot one. In order to do this I'm going to need to acquire a 20 foot pair of speaker cables. I don't (can't) put my amp in the middle.

Based on my research it seems as long as the cable is well made, it shouldn't matter, at least 20 feet or under? I am worried that my sonics will suffer...