Disable Apache's AllowOverride directive
When the AllowOverride directive is activated, the Apache HTTP server must climb the directory tree in order to find a .htaccess file that might contain overloading rules. It is thus recommended that, if possible, you disable this directive in the Apache configuration.
Encode sound outside of the CMS
Adapt and optimize sounds outside of the website because a web server is not designed to perform such operations. This saves large amounts of bandwidth and lightens the load on the CPU and RAM.