A magnetic assembly for a speaker is disclosed. The magnetic assembly includes a yoke, a magnet module installed on the yoke, and a pole module mounted on the magnet module. The magnet module includes a main magnet, a first secondary magnet and a second secondary magnet, the pole module includes a main pole plate, a first secondary pole plate and a second secondary pole plate. The first secondary pole plate includes a first pole protrusion extending perpendicularly from an edge thereof, and the second secondary pole plate includes a second pole protrusion extending perpendicularly from an edge thereof. The first pole protrusion and the second pole protrusion are located facing two opposite side walls of the main magnet respectively.