To see what kind of sensors work well with the Arduino, look at these sites:
That IcubeX seems expensive.
It would be easier if you know what you want to detect.
Scratching and knocking can be detected with a piezo element or a cheap electric mic element.
But do you want to detect the location ? and how accurate ? how many locations at the same time ?
Touching can be done with the Arduino, like the Makey Makey : MaKey MaKey - An Invention Kit for Everyone - YouTube
A radar sensor could be used as motion detector.
I have read about an interactive sound or music wall many times. You will find some movies on youtube.