I wouldn't do that. The larger gauges favour the lower frequencies and vice versa. If you are running a single cable, you essentially have to compromise -- select a gauge that will work well enough for all drivers. A 12 gauge cable would be a good average for the needs of the 3 drivers. The benefit of going with 3 cables is that you can select the right gauge cable per driver, you don't have to compromise like you dio with a single cable. Hence, I would go with 10g for the bass driver, 12g for the mid range and 14 g for the tweeter.