I dont think the field itself makes it permanent, because its not about changing peoples personalities.
More like changing the ambient affecting the moods at that moment when played and for the hours the effect lasts after.
But with consistency i do believe a heart to heart connection can be created when the other person stars embracing you, trusting you, accepting you and then it could organically change the normal behavior from someone towards you.
There are people that are very closed off and exude a cold angry mood but its nothing more than fear of being rejected or hurt but if you have the merits to be someone that x person can trust without the fields effect, then the field would help them to open up and once open, they would see that they can trust you (even after the field has worn out)