If the new floor happens to be one of the laminate floating ones, flat style speaker wire could have gone under it.
Less hassle is important, of course. You could get through the floor with a discrete small entry hole into crawl space & likewise at the other end.
Make sure you understand which direction joists run. Almost anything can be accomplished when wanted to hard enough. Wire fishing can be nearly miraculous.
Best of luck.
What ever happen to the Home theater forum on Cnet where they showed different audio/video theater setups from different homes? I enjoyed looking at the pictures and getting different ideas. I need help, I just put down a new floor, and I do not want to put holes in the floor to run wires to the next room, I will do it only if I have to. Is it best to run wires through the wall or underground? I have a crawl space. Share some of your thoughts and designs.