punctuation - Where to put the periods when using a parenthetical sentence?

I have two complete sentences; the second is in parentheses, essentially a comment on the first. Where do I place the periods? I would use this:

They played opera. (I covered my ears.)

Is this punctuation correct?

Answer

Punctuation within parentheses

If your parentheses enclose a sentence-within-a-sentence, don't use a period within the parentheses. Do, however, use a question mark or an exclamation point if it is called for.

Mother love (hers was fierce) ruined
the young boy's life.

They finally said (why couldn't they
have admitted it earlier?) that she
had been there.

The wedding reception (what a fiasco!)
ended abruptly.

If the parentheses enclose a complete sentence that stands alone, keep the period within the parentheses.

(Her father was the only one who
didn't attend.)

From Cliffsnotes