I started cycling last year and started riding the bike paths. First i would call out "on your left", to peds first thing usually is confusion. Other roadies i use On your left. Horses i always stop, or if room pass way wide. Used to use earphones all the time.
Now i use"COMING THOUGH" very loudly, this works much better as peds will move which ever way they are going to go and i can take the open spot or stop if needed.
Now i leave the ipod/radio at home, my cycling has improved because i am paying attention to what i am doing without drifting off. I thought i would get really bored but i don't.