Does it make any difference to google if you name a backlink: http://example.com/music/ or http://example.com/music/index.php ?
From an SEO point of view, no it makes no difference. They are 2 names for the same page. From a practical point of view the first example is best. It is not better to create a subdomain. There was a time years ago when G treated the subdomain as a totally different website so links between the two were considered external. That is no longer the case.