I discovered recently that some only do it when you push the button for blind people by mistake, but I don’t think that covers all of them. Any theories?
Why do only some pedestrian crossings make sounds or play music?
June 27, 2008 at 10:02 pm (Japan FAQs and SAQs)
Japan Explained FASAQ 
Tom said,
June 30, 2008 at 6:47 am
Theory: the sound is annoying so they don’t want to play it all the time. I’m sure that the yellow path for the blind has a big square there so they know to stop and that they are at an intersection.
Yoshimaru said,
July 22, 2008 at 7:03 pm
as it is stated in wikipedia:
“The tune being played at Japanese pedestrian crossings is an analogy to this game i.e. it is safe to cross until the music stops.”
This is in reference to the cute Japanese folk song “Toryanse”…
alexcase said,
July 23, 2008 at 1:15 pm
Thanks guys. Still, some crossings never seem to play any tune at all. Just old ones? Near houses they will annoy?