Crystal song

I have been working out how I want the energy crystals to work in the game, as they are needed for almost everything that get's created.  I want them to be fairly easy to find yet not so easy that finding them becomes so common that they become a non issue.  To this end I have come up with a nice workaround.  I plan on making the crystals sing.

So I can hear you asking, how are they going to sing?  I plan on making a crystal room that will be fairly large and have multiple connections to the surrounding caves.  This room will only happen on the mid or lower cave levels, and I will have to work out just how many of them per hexfield will be needed.  In the room it will be top to bottom full of crystal blocks.  Blocks will be randomly assigned a tone relating to the midi scale, and there will be a constantly repeating "song" that the blocks will play.  I have already composed this song, and I will post it to soundcloud probably later on today so you can hear it.  Anyway when a player is getting close to the crystal the song will get louder.  I plan on having the crystals emit a low level light source, and when singing the light will become slightly stronger.  When players interact with any of the crystals in the room the song will stop and only the crystals getting hit by melee weapons will play.  This means that players will be able to play little songs if they want to coordinate their efforts.  Builders again will be the only ones able to actually get crystals and fill up their bags and anyone else who happens to be with them.  After a time the song will start again, leading players back to the crystal room.  I plan on using simple MIDI to accomplish the song and the crystal playing by players.  Since this will be one of the few places in the game that will have music, it should provide a the needed guidance to players to meet their crystal gathering needs.  It will also mean that enemy players will be able to know if there are other players in a crystal room as there will be the player controlled sounds emitting instead of the song.