Evanspa21,
Is the song in MP3 format and can I download it from Napster! 
Some use singing to occupy the conscious mind during PR, others use the mantra's of their choice ... so as long as it does not bother you, use it to your advantage.
Concentration is achieved by making a time commitment and using the tangerine method.
The mantra is meant to 'occupy' the conscious mind while PR'ing so as to not to interfere with the sub-conscious mind.