Out-of-the-Box Setups
Suggestions
Basically, if you want to show your custom fields in the audio detail page you just add {$item.audio_lyrics} and {$item.audio_credits} (assuming they are the correct field names) to the jrAudio item_detail.tpl template, where you want the values to show. So, using the current template as an example, at lines 37 and 53 add this code -
<span class="info">Credits:</span> <span class="info_c">{$item.audio_credits}</span><br>
<span class="info">Lyrics:</span> <span class="info_c">{$item.audio_lyrics}</span><br>