50's B&W english film I believe... story line is about a young boy who doesn't like his piano lessons... falls asleep and dreams he is in a large room with a piano keyboard that goes all along the wall continuously and has 40 or more other boys trapped by this mean piano teacher... kid does something wrong and is taken down an elavator to the dungeon... a black dude calls out the floors as they go down... 3rd floor dungeon - ankle chains, neck chains... the trapped boys concoct some kind of liquid in a bottle that sucks up all the musical sounds when they take the top off the bottle and overpower the nasty piano teacher... the piano key board stretches all the way around the circular wall of the room and the boys are forced to practise side by side... sure would appreciate anyone knowing the title... thanks
