The following Looping audio players' prestine looping depend on the quality of your internet connection and browser performance.

 

Files with LP means the end and start are the same sounds.  Without LP means it should be at the beginning.  To make the beginnig play once and go directly into the loop. Look up OGG looping.  Otherwise program it in your software engine or make all the loops you want and export it using a wave editor. (Audacity)