$re = '/(.*) \(/m';
$str = 'Artist - Title (12") (Warner Bros - WB1210)
Artist - Title (12", Promo) (Warner Bros - WB1212)
Artist - Title (Summer Mix) (12", Promo) (Warner Bros - WB1444)
Artist - Title (12", LP Album) (Warner Bros- - WB9449)
Artist - Title (12", Red) (Warner Bros - WB1211)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php