My Gosh, it's so hard to seek out a necessary sample (ripped from KOF '94 with YM2610 ADPCM Decoder) aurally!

I finally added the fist or leg swing SFX during player's attack, but for some reason the playback of this samples is distorted. Does anobody know why?
Also I'd like to ask you to warn me if samples I used is wrongly found in fact (I searched a sounds of Terry's weak and middle punches and kicks).