The classical piece that plays on the radio is "Siegessymphonie" (Symphony of Victory) from Music to Goethe's tragedy "Egmont", op. 84 by Ludwig van Beethoven. At the end of the play right before this final piece of music plays, the protagonist dies calling for liberty.
I wonder if that's why the freed bird likes the song so much...
For those who are stuck on the drink puzzle: Check the painting with three different shaped bottles - they look like wine, water jug and absinthe. Note the direction of the lines (wine=horizontal, water=vertical, absinthe=diagonal). Now check the painting with the bottles and glass set up. Look at the lines to see which drink should go where, and match accordingly (use the drinks) on the real items.
It's in the works, don't worry ;)