Response headers for an mp3-file when NOT using RewriteRule

Cache-Control:must-revalidate, post-check=0, pre-check=0, private
Connection:Keep-Alive
Content-Disposition:inline;
Content-Encoding:gzip
Content-Transfer-Encoding:binary
Content-Type:audio/mpeg
Date:Sun, 12 Feb 2012 15:24:49 GMT
Expires:0
Keep-Alive:timeout=15, max=70
Last-Modified:Sun, 12 Feb 2012 15:24:49 GMT
Pragma:public
Server:Apache/2.2.16 (Debian)
Transfer-Encoding:chunked
Vary:Accept-Encoding
X-Powered-By:PHP/5.3.9-1~dotdeb.3