I’ve had a look to the source code of your page and the soundy source code is correct: the loop attribute is in the audio tag.
I’ve accessed the page with Google Chrome, Safari and Firefox on my mac.
The first time it didn’t loop in Chrome but then, I refreshed the page and it did loop.
In Safari, it doesn’t loop.
In Firefox, it loops.
I’ve installed the crickets.mp3 file on webartisan.ch and set it as background sound in the page:
https://webartisan.ch/test
Here it loops in my all three navigators.
It looks like the problem is not bound to Soundy, nor your file. There might be a caching issue on your hosting server.
To test this, could you use my copy of your mp3 file on your page. The URL of the mp3 file is: https://webartisan.ch/wp-content/uploads/2014/04/crickets.mp3
And let’s see if it loops like this.
