Alternative to libraries_get_path() to get a JavaScript file path
You can get the same data using drupal_get_library(), but it's not in a friendly format so you'll have to dig into the array yourself. For example, the following code will get the same path as your current code but in a much less less satisfying manner (in my opinion anyway):

$lib = drupal_get_library('soundmanager2', 'soundmanager2_debug');
$sm_path = array_shift(array_keys($lib['js']));


As I understand it this is actually the reason there's a need for the Libraries API to exist...so this sort of thing can be managed in a structured manner.