I have used a PIR..and it work good because I need play a voice I have to use a Wave shield ..that work only at 12 bit!!!!
12 bit is impossible, no one software convert wav in this format!!!
Are you sure it's an actual Wave shield
from Adafruit? Those boards use 16-bit .WAV files, not 12-bit.
In any event, Audigy
is a free open source software program I've used for sound recording, editing, and file conversion. Although it doesn't support every type of audio file, it does support several so perhaps it includes the type you need.