The Yonge–Dundas installation was mentioned in the Toronto section of last Saturday's Globe and Mail. It's probably behind a paywall by the time you read it, but a tasty quote from the article says:

Much like the searchlight installation that lent an icon to the festival last year, the installation will let people play with light on a grand scale. David Pecaut, Luminato's co-chair, says he sees it as a kind of home base for the festival this year - and one that intractably ties itself to the city's landscape.

Rad!

After much ado, the microphones are I think being installed today. The whole thing will be operational for testing on Thursday night, and officially running as of Friday.