When They Come For Me "Live" equipment question

In any live performances of "When they come for me", during the bridge part, Mike hovers his hand on this box. I would like to know what it is.

http://www.youtube.com/watch?v=3vP6sGyw9Lw

It's at 3:51

 

He's feeling the vibrations. Or is checking how hot it is, afraid that it would kill the power of the whole arena.
Or I don't know... =)

 

I think it has to do something with controlling sound or an effect. In every video he does it lol

 

It doesn't seem he has something in his hand like a remote control though... or I didn't see it?

 

It's a Theremin. I can't really hear it so it must be mixed pretty low, or they are using it to control the arpeggiated synth filter.

http://www.flickr.com/photos/nataliaalmeida_shinoda/5078891393/

http://upload.wikimedia.org/wikipedia/commons/c/c8/Etherwave_Theremin_Kit.jpg http://www.youtube.com/watch?v=cd4jvtAr8JM&feature=related

 

Wow, this is so cool! I love the video on Youtube!

 

He uses the theremin on New Divide as well.

 

Oh boy that's just super cool! I didn't know we have these inventions!

 

It used to be very popular for old-school horror movie soundtracks. NIN was well-known for using it 'reversed' during the Fragility tourd.

 

This is great to know! I know nothing about gears, i'm so not a musician /cool story

 

Longer in-depth post I wanted to make (that last post was via phone on the way to work):

The fun thing about the theremin is that as a touchless instrument, there's a wide variety of note ranges and volumes that can be attained. Swells in volume and note changes are all smooth and can be very dramatic.

The ideas behind why the theremin is fun is also why it's so difficult to learn. While there are a wide variety of notes, it IS a touchless instrument, so you have no basis to judge if you're flat or sharp until the note is already played. I've had my hand at playing this instrument a few times and it's really difficult to play anything with a clear purpose (i.e. an actual song someone recognizes) without intense years of training.

Then you have people like this that make you want to quit life forever:

[youtube]adtW7nZHmkg[/youtube]
This man is god-like. Fear him. Have his babies.​

To be more LP-centric, what Mike is using is (my guess) a Moog Ethervox, which uses the principles of a theremin to act as a MIDI controller. In the case of WTCFM, he's using the Ethervox to control the volume of the arpeggiated synth, as Justin V. so accurately guessed. What is typically the left hand side of the instrument (unconventional use is fairly common, as most theremin enthusiasts support finding new ways to use the instrument and actually frown upon adopting an 'official' technique) controls volume depending on how close your hand is to the metal loop.