What floor is this room on? Though it might be easier to route the cables straight along to the first speaker and then over to the second from there, you'll have well over 16 ft in cable length by then. I'd say cut diagonally from the rack straight to the second speaker (left).
Also, you could just use wire rated for in-wall use vs. installing pipes. I'd just pack the hole around the wire with a permanent flexible putty. So you may want to look at the cost benefit before you start ripping out parts of your floor that might have been better left alone. Just my opinion.
Also, you could just use wire rated for in-wall use vs. installing pipes. I'd just pack the hole around the wire with a permanent flexible putty. So you may want to look at the cost benefit before you start ripping out parts of your floor that might have been better left alone. Just my opinion.