This is a quite interesting post!
I also would like to find a way to reduce the volume of the melodica.
For playing at night, to not upset my family inside the house and also the neighbors.
Normally I compose a melody during the day time, and I go on practicing it trough the night, playing the melodica really low.
Quite often I am playing so low, that a lot of keys don´t even can be heard. This is not a bad thing per se.
The problem is that it is hard to improve the melody, and of course composing new ones.
Sometimes I get a bit frustrated because normally it is at night that I feel more creative.
I guess there is more creative energy during nighttime than during daytime.
So I think I will try this box idea.
Maybe it would be a temporary solution for this “problem”.