I lead a game-development team. My sound designer gave me some sound effects as 32-bit stereo sounds with a 44100 Hz sampling rate. The game (actually a mod of an old game) requires sounds to be 8-bit mono sounds with a 22050 Hz sampling rate.

We're trying to export the sounds in the required format, but there are serious artifacts -- the resulting sound has a "ringing" effect, even in areas where the input was silent.

My question is:

1. Why is this happening?
2. How can we export the sounds and obtain a decent result?

Here's an example input sound:

<https://www.dropbox.com/s/96d8lmabt8608oa/Taking%20Damage.mp3?dl=0>

And here's an output: 

<https://www.dropbox.com/s/tk6ag6fp2pzb1pd/CBHMWNCE.wav?dl=0>