The browser is able to play back the audio files that Asterisk is recording. In my first post, I mention that I can "Save As" the audio file to the desktop and then open it with any browser. It plays back perfectly.
The problem lies in trying to open the audio file from the link provided in QueueMetrics, directly from QueueMetrics. Since QueueMetrics is forwarding us to a URL ending in ".do", the browser doesn't know what to expect, so it defaults to HTML. When audio/wav formatted data comes back instead, the browser fails to play it back because, as it states, "Resource interpreted as Document but transferred with MIME type audio/wav".
To summarize:
* Asterisk audio format is readable by the browser
* Tomcat is returning the resource with the right MIME type of audio/wav.
* The browser is refusing to play it because QueueMetrics is sending the browser to a ".do" file URL, which is not the correct extension for audio.