Long speaker Wires.
Then, if still needed, down, thru crawl space without conduit.
Over the years, many locations, I've had very long speaker wires successfully. I've drilled holes against the walls down to my crawl space in many locations, for cable tv, coax, ethernet, signal, speakers, sub, rear surround, outdoor speakers, shop speakers. All without conduit, never an issue. Make sure you don't have mice.
Test: start with inexpensive heavy gauge lamp cord (1 strand marked). After that, you will be pleasantly surprised, then, if you must, upgrade those speaker wires in the future.
Once I made 50' long pairs out of solid core strands from electrical supply house, twisted them, they sounded as good as prior and later cables.
It's by trying stuff that you learn many 'inadvisable' solutions work well.
Then, if still needed, down, thru crawl space without conduit.
Over the years, many locations, I've had very long speaker wires successfully. I've drilled holes against the walls down to my crawl space in many locations, for cable tv, coax, ethernet, signal, speakers, sub, rear surround, outdoor speakers, shop speakers. All without conduit, never an issue. Make sure you don't have mice.
Test: start with inexpensive heavy gauge lamp cord (1 strand marked). After that, you will be pleasantly surprised, then, if you must, upgrade those speaker wires in the future.
Once I made 50' long pairs out of solid core strands from electrical supply house, twisted them, they sounded as good as prior and later cables.
It's by trying stuff that you learn many 'inadvisable' solutions work well.