Nightingale floor? Okay,a quick little footnote like explanation for those of you who really don't know.
You know how wooden floors sometimes creak (or even squeak) when you step on them, right? Okay, before we got modern high technology some people would intentionally have their floors (parts of them anyway) made squeaky to use them as primitive burglar alarms. Rich people who didn't like squeaky noises would even pay master artisans to construct floors that made sounds like bird song when stepped on! I have never seen or heard one, so I'm not sure if they actually managed to mimic the song of the nightingale or they just got that name because they were built to "sing" at night, but anyway that's what a nightingale floor is!
And like so many other inventions of the past, the secret of their construction is long since forgotten. Even with our most modern design and construction tools we are unable to mimic the masters of the past. Or the nightingale, for that matter.
Then again, with our technology it would probably be easier to wire up a pressure pad to a sound syntheziser anyway...