On GotSound.org we are using wavesurfer.js to play sounds in a browser.
It's works only in modern browsers supporting Web Audio.
MediaElement fallback to support old browsers like Internet Explorer not always works.
You can find more information about browser supported Web Audio API here.
Please, consider to upgrade your browes to one of the following:
Close field recording of medium ambient waves crushing on the shore of Kalundborg Fjord at Røsnæs. Water cascading through small stones as it pulls back into the ocean. Very distant vessel. Recorded at 2 meters distance, 120 degree with Zoom H2 build in microphones mid February. www.luftrum.com