we'll i've never had any problems with echoes so i don't know, lol.
to play a wav file you need 3 things...
1) A handle variable that allows you to control the sound (e.g, tuning, volume).
2) A SOUND* pointer to your wav file.
3) The snd_play function, to actually play your file.
SOUND* my_wav = "wav_file.wav";
var wav_handle;
wav_handle = snd_play(my_wav,100,0);
That should work.