Alternative to tuning automatic hub? I am contemplating purchasing an automatic gear hub, namely the SRAM Automatix. One of the criticisms leveled at this hub is that it shifts up too soon. The default settings can however be adjusted if know what you are doing, as this article explains: 

http://mccraw.co.uk/sram-automatix-review/

Would using a smaller chairing on the crank-set have the same effect??? 

(I would rather do this than mess with the delicate innards of the hub axle).
Unwinding the spring, as the article states, will make the hub to shift when you're going faster.

Without touching the internals, the hub will shift at the same speed, no matter how high the cadence is. By changing the chainring-cog ratio you adjust the cadence at which the shift-speed is obtained.

So the answer is no, there is slight difference. By doing what you propose you can make the whole set shift at higher cadence, but at the same angular velocity of rear wheel, so at the same speed.

If you want to shift at higher speed without modifying the hub, you need bigger wheel (if possible).