i think not terrible. im not sure if you hear it, but i do whenever a monitor is turned on. i could be at one end of my house with the door closed, and i could "hear" the tv being turned on, before any sound comes out.
i used to be fascinated when i was small, because when i used to turn on the tv it used to be so loud in my ears, yet my parents never knew until they looked at the tv. but sometimes it has been annoying because i hear it when nothing i can see is on, and it takes forver to stop.
and it is kinda like a whining sound. not really ballet material