Dont replace the "\n" to "<br />" when you insert them to database. Instead use nl2br() function when fetching results.
Ofcourse you can do SOME parsing and formatting to the text when inserting to database. Atleast:
$ade = mysql_real_escape_string($_POST['lyrics']);
..to make it safer to put to database.
Also its maybe better to strip html tags also:
$ade = strip_tags($_POST['lyrics']);
$ade = mysql_real_escape_string($ade);
Now when you insert those lyrics to database, there are no tags but newlines will remain and you can use nl2br() when showing them.