Dean Bowditch, 34, of Hirwaun, near Aberdare, admitted three charges of common assault.
He flew into a rage when non-stop drum and bass music from next door was interfering with his son's revision.
Merthyr Tydfil Crown Court heard Bowditch burst in to confront the three men who were using record turntables.
Tony Trigg, prosecuting, said: "He hit the earphones from the head of one of the surprised men.
"Then he slapped another across the face before going to the kitchen to get a six-inch knife.
"He pinned the third man against the wall and made cutting movements with the knife towards his throat.
"He was shouting that he was going to kill them all."
The court heard Bowditch thrust the knife into a cardboard box as he left and told the trio: "You've heard the bark - you are going to feel the bite tonight."
Judge Richard Twomlow said that the offences were so serious that an immediate prison sentence was called for.
