How to hide audio url

Unfortunately by default this is not possible. When you embed an attachment ( audio, video or image ) the URL from your wp-content directory is visible.

A quick google search yields this plugin: https://wordpress.org/plugins/hide-real-download-path/ – which claims to hide your original download path.

You might also consider hosting your audio at SoundCloud and using WordPress’ oEmbed system to just drop in the soundcloud player.

More Info on oEmbeds: https://codex.wordpress.org/Embeds#Okay.2C_So_What_Sites_Can_I_Embed_From.3F