I'm running 17.04 on an Acer Aspire V15.
So my backspace key works normally except.... when the cursor is in a terminal window and I haven't typed anything into the terminal, pressing the backspace key when there is no text to delete produces a single click, holding the backspace key repeats the noise rapidly from the speakers. It has a slight delay before the clicking starts, and it's the same delay that occurs when you hold backspace to delete characters, before they actually start getting deleted. This only occurs in the terminal, as far as I can tell. Empty text fields in other programs don't have the same effect, and when in the terminal as long as I'm actually deleting something the clicking doesn't occur. If I type something into the terminal, then delete it by holding backspace, the noise doesn't occur until all the text is deleted.
It's definitely a software noise, because it disappears when my volume is muted
So basically, holding the backspace key in an empty terminal produces a clicking noise. I have no idea where to even start diagnosing this. Is there a list somewhere of packages that affect terminal behavior?