<p>I am writing a dhtml application that creates an interactive simulation of a system.  The data for the simulation is generated from another tool, and there is already a very large amount of legacy data.</p>

<p>Some steps in the simulation require that we play "voice-over" clips of audio. I've been unable to find an easy way to accomplish this across multiple browsers. </p>

<p><a href="http://www.schillmania.com/projects/soundmanager2/" rel="noreferrer">Soundmanager2</a> comes pretty close to what I need, but it will only play mp3 files, and the legacy data may contain some .wav files as well.  </p>

<p>Does anyone have any other libraries that might help?</p>

I believe that the simplest and most convenient way would be to play the sound using a small Flash clip. I appreciate it's not a JavaScript solution but it IS the easiest way to achieve your goal
Some extra links from the previous
similar question
:
Scriptaculous, a Javascript library:
http://github.com/madrobby/scriptaculous/wikis/sound
an opensource Flash project: Easy Musicplayer For Flash
http://emff.sourceforge.net/