Thanks to all who sent suggestions and audio recordings in response to my first challenge. Quite a few people mentioned the three-tone Toronto subway chime as a signature sound of the city. Listen:

Now I’d love it if people would really open their ears, stretch their imaginations and think of a sound that’s both unique and unusual, something no one else will have thought of. Can you send it to me by next Wednesday? Once we have enough sounds, I’ll schedule a live Twitter session to talk about the sounds and answer your questions!

– Tod