Hey thanks for using fixya
Actually by default there is no any trick to listen fm without earphone. If u want to listen not from he headphone, then its better that just attached the headphone with Handset, Now go in options of Radio, There is option as "loudspeaker" now you can listen fm from loudspeaker.
Enjoy

I hope it 'll be helpful for you.
Kindly keep thumbs up for rating.
Thanks