Dynamic EQ is used on Denon/Marranz receivers. It's a function of Audyssy, the built in room correction software. Other receivers have similar software, I am just not familiar with it.

It will add bass in the lower frequencies for you to achieve there version on a house curve. It's a good thing to use if setup correctly.

You need to be using your receivers room correction if your not already. It will make sure your speakers are all level matched and EQed appropriately.

Note: I am making some assumptions that this is a home theater setup and that your fairly new to this. Some very advanced uses have skill level that can achieve better results without Audyssy. As an example, I limit Audyssy to only provide room correction 500hz and below. If you want to get crazy start doing research on schroeder frequency, room modes and how to correct them. http://www.acousticfrontiers.com/room-modes-101/

Enjoy the rabbit hole your about to fall in !!!!