mp3 audio works in all browsers but not IE9

I have three mp3 audio files that play fine in all browsers but play for only 1.x seconds in IE9 unless I change "controls" to "autoplay" in which case it plays just fine.

I was then sent the original, unedited file in .wav format. I encoded it myself to mp3 but have the same problem.

However, if I create my own mp3 audio file and insert it into the same markup, it works in all browsers, including IE9 with the "controls" attribute.

I can only think there is something about the settings in the original audio file that would cause the issue but don't have a clue what that could be.

Here is the test markup:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title> 
</head>
<body>
<audio src="poem.mp3" controls >
</body>
</html>

EDIT:

I put three audio files on the page. Sometimes one or two will play all the way through while the third won't play at all. Other times, two will play for a second but the third does nothing.

Solution

EDIT: My fix didn't work. It still fails in IE9 but everything works still in every other browser.

An answer to my own question that solves the problem, at least, but I have not found out why.

I don't know why some mp3 files play just fine in IE9 but others, that also work well in any modern browser, won't play in IE9 using the markup I show above. I made audio play by adding the audio attribute preload="auto" and all is fine now in IE9.

Modern browsers do not need this. Why IE9 does, I do not know yet.