On carriage return, the sound should be a slow swing of the heavy carriage physically returning.
It also, probably more so, was a signal to the user to start thinking about how to break the current line. You couldn’t type and, upon realizing the word you were typing didn’t fit the line, backspace and type a hyphen.
‘About ten columns’ then is a reasonable number. Of course, longer words exist and aren’t extremely rare, but those would have a reasonable hyphenation point that you could and would want to use.
Those IBM selectrics were overbuilt. They vibrated and hummed when turned on.
The bell rings when the Page Stops are reached. These can be manually set on the page. The bell rings, the typist plans for end of line, then they whack the bar and zzzzz-thunk the carriage returns.