Good !
I've learned something new tonight (i am also a new OSX user !).
Another strange thing happened : i did not shut down the imac yesterday nor changed any settings) and when i cheked audio search today, all the options appeared (by title, artists ans so on ...).
It must be the magic of christmas ...
Anyway, thank you for your replies.

Jean-Marie EDQUIST
edquist@stimtech.fr