Using a custom field as a filename in Audio Player

Hi there,

I’m trying to work out how to use a custom field in my theme to display an Audio Player with the audio file named in that custom field within each post. This is my somewhat disastrous attempt:

<?php if (function_exists("insert_audio_player")) {
  insert_audio_player("[audio:<?php $key="audio"; echo get_post_meta($post->ID, $key, true); ?>]");
} ?>

… which gives me a parse error.

I’ve search around but can’t seem to find the same question anywhere else.

Any help much appreciated!