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:
Recording of me knocking on my desk. Rhythm variations.This is a recording of my own and you may use it for any commercial or non-commercial project without the need to credit me. I would just like to know for what it is used in the comments below but that is completely nonobligatory.