Should I Calibrate My Home Theater System?

Are the differences truly noticeable? 

You would be surprised to know how often this comes up - do you need to use your AVR's room calibration when setting up your system? Though we can give a long detailed answer breaking down every nuance, the simple answer is YES. 

You must re-run room calibration every time you change speakers, subs, amps, etc.. Almost every AVR/Processor will come with room calibration software and a microphone needed to run it. It won't take too long and it will truly elevate your viewing experience. Room calibration will help get the most out of your gear, which is what we all aim for! Now, it's not foolproof - sometimes, making changes after the fact will yield great benefits. Making tweaks once the software has finished is your decision - you might want to experiment with different crossover points, change distances to eliminate nulls in your sub response, etc. At the most basic level, you should always measure distances, levels, and gain match your subs. The good news is that you'll be off to a great start once your calibration is uploaded to your device. 

To learn more about your AVR's calibration software, make sure to check YouTube and the various forums - no two software's are the same!