What causes the "ripping cloth" melee noise?

[Tecmos Deception]

You know, when you get hit hard by an NPC it sometimes makes a special "you got hit extra hard" sound instead of your character just grunting?

I always figured, without any extra thought, that it was when you got hit for a certain amount of your health or the monster's max hit or something. But just now I watched an 84 hit against me make the noise, then the next melee round an 88 hit me and did NOT make the noise.

Obviously a minor detail, but my inquiring mind likes to know.