<p>I have a 10 second sound effect wave file. What I would like to do is take that file and repeat it n number of times and then save the longer WAV file to disk. This way I can create a much longer background effect rather than auto-repeat on the media player which is a bit stuttered between repeats. I am trying to do this in C#.</p>

That's reasonably easy to do, given the
WAV file format
- assuming it's uncompressed audio (most WAV files are - or at least, they were last time I had anything to do with them).
There may well be audio APIs you can use to do this without getting stuck into the binary format, but I suspect they'd take as long to learn as just doing it yourself as you're not doing anything particularly complicated.