EAX is covered at length in this thread:
http
/www.tomshardware.co.uk/forum/259210-28-what-deal
DirectSound3D is part of Microsoft's DirectX software found in all Windows versions from XP and up, and in no way compares to EAX which is both hardware and software based, though admittedly it's somewhat old technology now, largely redundant unless you are still using Windows XP for gaming.