smurf tube's tough to get many speaker cables through because it is corrugated, fairly small and flexible whereas PVC or ABS is smoother, but takes longer to install (and can be more difficult because of its larger diameter needed to accomodate your fat cables)
Pbb, installers and people do what you suggest and have done it for a while, it's a smart idea and works well, provided you allow for the actual pulling of the cables and the fact that many hi-end cables are jacketed with materials that are not slippery or durable enough to put up with more than about 2 bends without causing major problems and occasional damage due to friction in the conduit (and who wants to smear their expensive cables with the fancy jacket with conduit lube- kinda kills the resale...)
Cables (speaker or interconnect) with networks also pose a problem. At least one cable manufacturer offers speaker cables in different performance levels with a Neutrik wall plate that attaches a pigtail with the network on it. They don't comment on the effects of adding those connections to their cables, and claim the network takes care of any problems as a result.
Lastly, don't tie the end of the new cable to the end of the old and pull away. Pull a piece of nylon cord through the conduit with your old cable on its way out, then use the strong, thin cord to pull your new speaker cable. It's half the friction that way.
Pbb, installers and people do what you suggest and have done it for a while, it's a smart idea and works well, provided you allow for the actual pulling of the cables and the fact that many hi-end cables are jacketed with materials that are not slippery or durable enough to put up with more than about 2 bends without causing major problems and occasional damage due to friction in the conduit (and who wants to smear their expensive cables with the fancy jacket with conduit lube- kinda kills the resale...)
Cables (speaker or interconnect) with networks also pose a problem. At least one cable manufacturer offers speaker cables in different performance levels with a Neutrik wall plate that attaches a pigtail with the network on it. They don't comment on the effects of adding those connections to their cables, and claim the network takes care of any problems as a result.
Lastly, don't tie the end of the new cable to the end of the old and pull away. Pull a piece of nylon cord through the conduit with your old cable on its way out, then use the strong, thin cord to pull your new speaker cable. It's half the friction that way.