In Harry Potter and the Goblet of Fire, a character bearing this name (Cedric Diggory) was the second winner for Hogwarts shool along with Harry Potter. Cedric was famous in the series for being the character who Harry saw die, enabling him to see Thestrals.
Cedric Diggory made his first appearence in the third Harry Potter book, Prisoner of Azkaban. He was the captain and seeker of the Hufflepuff Quidditch team, and therefore one of Potter's main rivals.
I have a family member who came from "Sedretch" Hungary. It was a small town. I could not find it on the web. I did however find some families trying to discuss their LAST name or a name in the family that sounds like Cedoric, or CSDoric. They where wondering about the spelling, and about the pronunciation, mentioning someone of Hungarian origin. I have found Sedritz as the name of a black violinist in the US.
For some reason this name brings a picture of a evil, egoistic and extremely intelligent character of a fantasy book to my mind. But as I happen to love both fantasy books and the bad guys in them, I LOVE this name too. It sounds very noble to me.
Despite my immediate association with Cedric the Entertainer, I still think Cedric is way too old-fashioned a name for me to ever use. For a character. Maybe. Definitely not for a person, though.
I've always heard it SED-rik, but I was watching a movie called Love In A Cold Climate, where one of the characters was called SEED-rik. The actors were British.