Now, I'm terrible at making a thread so I'm going to keep it short, so, I'm building a Mob Farm and I'm looking to find out what the changes are in regards to mechanics, so I can design my spawner to be custom built around this. Few things, What's the spawning radius from a player in each direction, is it a square of a sphere? Does the Y coordinate matter in these calculations? And finally, what's the activation range of a mob? (The distance you have to be in before the mob will walk around)
mobs spawn in a 9x9 chunk area with you standing in the center chunk. Mobs do not spawn within 32 blocks of u. Y coord doesnt matter. (all this is if its natural mob spawning youre talking about, and not a actual dungeon-spawner)
I'm pretty sure that's not right - on EMC it's set up so mobs spawn closer than normal. Both of the values you provided are larger than the default values. Can you provide a link to where you read that?
As far as I'm aware, it's a smaller range they can spawn in, I'm not sure though, I know an awful lot about spawn ranges in Vanilla, but it changes so often in EMC I loose track.
The thread containing all of EMC's changes from vanilla mechanics, including mob spawn info, can be found HERE
the min is the same, max is limited to 4 chunks instead of 8 of vanilla, (so 5 counting the one you are in, 9x9) that thread should detail it good. It was never reliable to go beyond the 4 chunks anyways for farm as monsters do not move much outside of 32 blocks in vanilla itself.