I purchased the Onkyo 502. It has been about 10-15 years since I had a new receiver. On the Onkyo speaker setup, they have test tones for your speakers where you can increase the decibel level for the speakers. I am only running two channel stereo through M60's. My question is why or is their any reason to turn up the decibal level for the two speakers. Won't turning up the volume accomplish the same thing? I'm new to this. Can anyone tell me the benefits of turning the decibels up or down? Thanks......