find + ffmpreg solution:
find ~/Music -type f -iname "*.wav" -exec sh -c \
'bn=${1##*/}; bn=${bn%.*}; ffmpeg -loglevel 16 -i "$1" "${0}${bn}.flac"' ~/Music_Flac/ {} \;
find + ffmpreg solution:
find ~/Music -type f -iname "*.wav" -exec sh -c \
'bn=${1##*/}; bn=${bn%.*}; ffmpeg -loglevel 16 -i "$1" "${0}${bn}.flac"' ~/Music_Flac/ {} \;